TPS Connector and Injector connectors off mk1a please

[Evo4Jon]

Hi

I am after a square type TPS Connector and the square Injector connectors off mk1a please. It will help me to test how the ecu's run with the other componants and whether adding more resistance to solenoid resistor makes car run differently to using High impedance injectors via EManage ultimate. (which requires higher impedance injectors

I am looking into what bits run with what so that if someone has a non runner then the part numbers can be matched up easily, or also for anyone who wants to mod their cars setup. They will know what they will need to do so that the fuelling can be modified without ecu failure etc.

I would like to get this info (below) accurate and make it a sticky on the site so it can be used by others... I have concluded the following from research on this site and others around the net

It seems that there are 3 ECU's and 3 types of injector for our UK cars
89661-17030 Nov 1984 to Aug 1986 injectors are grey and high impedance 13.8 Ohms - need to research config of this but if you run an early ecu on a later car then fuses blow apparently!
89661-17070 Aug 1986 to Aug 1987 injectors are Red but square connector and high impedance 2.3 Ohms wired in parallel with a 2-3 Ohm resistor pack = 4.15 Ohms load per channel on ECU
89661-17140 Aug 1987 to Dec 1989 injectors are pink with rounded connector and low impedance 2.3 Ohms wired in parallel with a 2-3 Ohm resistor pack = 4.15 Ohms load per channel on ECU

TO go with the ECU's above there are 3 x TPS for the UK car
Throttle position sensors:
89452-28010 AISIN - Nov 1984 to Aug 1986 (square plug connector)
89452-20070 Denso - Aug 1986 to Aug 1987 (square plug connector)
89452-12040 Denso - Aug 1987 to Dec 1989 (round plug connector)

Can anyone confirm this info is correct ?

Jonathan

[jimi]

These are the part numbers from the EPC that apply to UK MK1's
89452-28010 (11/1984 - 07/1986)
89452-20070 (08/1986 - 07/1987)
89452-12040 DENSO
89452-12050 AISIN
But I have no idea which shape plugs they have

[jimi]

This can't be correct

It seems that there are 3 ECU's and 3 types of injector for our UK cars
89661-17030 Nov 1984 to Aug 1986 injectors are grey and high impedance 13.8 Ohms - need to research config of this but if you run an early ecu on a later car then fuses blow apparently!
89661-17070 Aug 1986 to Aug 1987 injectors are Red but square connector and high impedance 2.3 Ohms wired in parallel with a 2-3 Ohm resistor pack = 4.15 Ohms load per channel on ECU
89661-17140 Aug 1987 to Dec 1989 injectors are pink with rounded connector and low impedance 2.3 Ohms wired in parallel with a 2-3 Ohm resistor pack = 4.15 Ohms load per channel on ECU
Both statements can't be correct. Normally if the resistance is between 1.5 and 4.0 Ohm they are low impedance injectors and if the resistance is between 8 and 16 Ohm they are high impedance injectors.

[jimi]

Also the load calculation doesn't make sense, 4 x 2.3 Ohms in parallel with 2 or 3 Ohms doesn't equal 4.5 Ohms more like 0.45 Ohms

[Evo4Jon]

3978

I calculated it from the manual. Please can you correct it if I have made an error ?
EDIT (YES I DID MAKE AN ERROR)
I Hadn't noticed the link between #10 and #20... So 2 x 4.15 Ohm resistors in parallel equal 2.07ohms and the load is on both #10 and #20.
I looked inside the ECU and both the channels are joined in the ECU ending in 070 and also the ecu ending 140 and the injectors all fire together as a batch

The injectors are driven in pairs and they sit in parallel to each other. 2 injectors with 2.3ohms each in parrallel is
1/2.3+ 1/2.3 = 0.87 and then 1/.87 = 1.149 (1.15)

1.15+ 3 ohms = 4.15 ohms for the loading on the no10 ECU input and the same again for the number 20 input

Both facelift cars run low impedance resisters so I thought the results would be the same for both as I have ran my Car on the 17140 and 17070 ecus and apart from TPS scaling being different the car runs but the fuel map is rather wild.

The High impedance denso injectors are 13.5 Ohms each and there is no resistor pack. I would like to see if the older ECU drives them in pairs or not though, but I dont think I have a diagram for the older 17030 ecu - do you ?

Thanks for replying :0)

Maybe this post should be moved by a moderator ?

Jonathan

[Evo4Jon]

These are the part numbers from the EPC that apply to UK MK1's
89452-28010 (11/1984 - 07/1986)
89452-20070 (08/1986 - 07/1987)
89452-12040 DENSO
89452-12050 AISIN
But I have no idea which shape plugs they have

I looks on google iages to see the TPS design based on part numbers and you can see on there of they are round or older square connector. The TPS ending in 050 is a rounded plug and off a super charger 4AGZE I think

[jimi]

The number ending in 050 is from the Toyota EPC for Europe which doesn't include GZE parts numbers but I couldn't say if any UK MK1's use it only that it's listed in the EPC under a UK VIN number.
My apologies, I didn't realise the injectors are wired in pairs which makes your calculation correct. Depending on the resistance of the solenoid resistors you get value of between 3.15 and 4.15 ohms per input. I may have a drawing for the earlier ECU, I'll have a look.

[jimi]

Just had another look at the drawing an it shows a link between 10 & 20 which changes the calculation. It means that both sets of injectors are in fact in parallel which changes the value to 1.575 - 2.075 ohms. Also means that according to that drawing all the injectors fire at the same time ??

[Evo4Jon]

I assumed that the 10 input would ground injectors 1 and 2 and the 20 would ground 3 and 4 as per firing order of 1342 so only the resistance inline with current flow would be utilised. If they were fired at same time then no need for 2 inputs to ecu.

Looking at the resistor on the car you will see it has 3 wires: a bat voltage+ and res1 and res2.
The resistors are separate to each other only joined by a common input V+. If 10 and 20 trigger (ground out) the circuit separately, then the 2 resistors will never form a parallel layout. This would only happen if both 10 and 20 were triggered (grounded out) at the same time.

[jimi]

You would think so, but the link between 10 and 20 means if you ground one you ground them both. The drawing for a car with an AFM doesn't show the link

[Evo4Jon]

I Hadn't noticed that lnk before !... So in fact the actual load is 2.07ohms per ecu channel if we treat the load on 10 and the load on 20 as 2 x 4.15 Ohm resistors in parallel and the injectors all fire together.

I have concluded that the injectors are Peak and Hold type based on the low resistance rating but I am struggling to see how the engine can run if the injectors are not fired in 2 batches ? Can you shed any light on this ? is it down to the width of the pulse ?

I have a feel that my Greddy ecu aint gonna be happy with this ! - even with the extra resistance I will be adding to the resistor box to increase impedance

[Sillyhatday]

The injectors all do fire at the same time, the 4AGE engine in general used MPFI (multi point fuel injection) as opposed to the more modern SPFI (sequential port fuel injection). The ECU only has one output for the fuel injectors, in the form of a single transistor. (There's two inputs to the ECU, but are linked internally) According to the internet, Japan had grouped injection in some cars. Which may lead to explain why the injectors are wired in two groups, so they could be easily wired together or split for other markets.

Effectively, the fuel air mixture sits about on top of the valves until they open and they are fired once per 360 degrees of crank rotation. Yes its crude, and sounds stupid, which is why with technology we have made systems to fire injectors separately. Benefiting in fuel economy and performance etc.

Remember these were released in 1984 and the car development started in the 1970s. Using early 80s tech they made a pretty good ECU. The ignition timing is done off a '3D' map. I barely understand it myself and I wont go into a much bigger tangent.

There is a LOT of information on the internet about the 4AGE ECU for both the MR2 and the AE86. Depending on how tech savvy you are it's worth reading. There's a bunch of people who have reverse engineered the hardware and software. I understand the hardware talk but the detailed software talk baffles me.

Have a look for a PDF online called lifting the lid on the mk1 mr2 ecu. It explains much better than I can :)

[jimi]

I'd forgotten about the articles by Jeremy Ross on the MK1 ECU :oops: I have a copy on my web storage, you can download it from here http://myweb.tiscali.co.uk/jlawson4/Jeremy%20Ross/Jeremy_Ross_Lifting_The_Lid_on_the_mk1_MR2_ECU.pdf

[Sillyhatday]

I'd forgotten about the articles by Jeremy Ross on the MK1 ECU :oops: I have a copy on my web storage, you can download it from here http://myweb.tiscali.co.uk/jlawson4/Jeremy%20Ross/Jeremy_Ross_Lifting_The_Lid_on_the_mk1_MR2_ECU.pdf

Haha, I did wonder. I found it really interesting :)

[Evo4Jon]

Thanks for the input ! ...Hmmm Looking at the Jeremy Ross article, it's looking more and more unlikely that by simply increasing the value of Solenoid resistor to give a higher impedance will work overall. It may stop the Emanage from blowing output transistors but I think the extra resistance will stop the Toyota ECU from working at all. I have just opened a 17070 ecu and Both #10 and #20 are indeed soldered to the same copper strip on the board and they both share 2 hefty transistors. They are not independent of one another. I never realised how amazing Honda 1992 ECU's were when I used to socket them, tune with a rom-emulator and create myself an eeprom - until now ! Toyota engineers were all over the place !

[jimi]

Forgot to say, I had a look at a copy of the MR2 electrical manual (dated November 1984) that I have and it shows the injectors (with no solenoid resistor) connected the same way as the later ones ie in pairs connected to 10 and 20 with a link between them.

[Evo4Jon]

Brilliant ! very useful thanks

The injectors were 13.5 ohms back then but that still means that the ECU saw only 3.375 Ohms if they were all connected in parallel. how very odd. I have been reading up on the differences of impedance and how it affects current flow etc. But 2.07 ohms vs 3.37 ohms is not what I was expecting at all !

Any chance you could screen print and upload the schematic please of the (17030) 1984 wiring?

[jimi]

Any chance you could screen print and upload the schematic please of the (17030) 1984 wiring?

I have it scanned, I'll put this link up for a couple of days, you can use it to download a copy of the manual, let me know when you have it so I can take the link down. ;)
http://myweb.tiscali.co.uk/jlawson2/UK%20MK1%20Electrical.pdf (http://myweb.tiscali.co.uk/jlawson2/UK%20MK1%20Electrical.pdf)

[Evo4Jon]

OK I have downloaded it ! Thanks Jimi !!

Yes the ECU sees 3.4 Ohms in that diagram with the 4 13.5ohms injectors in parrallel... The later models (mk1b) only 2.07 Ohms

if we take 14v as alternator voltage (max) current flowing through circuit in a mk1a is 14 / 3.4 = 4.11 amps
IN a Mk1b the current flowing is 6.76 amps

Peak and hold type injectors will see these current values as a spike and then the current will drop to a lower value once the injector is open. After market ECU's maybe dont have enough of a load to read what the injector is doing during the hold phase ?

[Evo4Jon]

Jimi, Do you have enough information to check which TPS is partnered with which ECU ?

My car is a 1989 mk1b with 89661-17140 ecu. I am curious to try the 89661-17070 on my car with the correct TPS.

When I connected the 070 ecu during testing for my fuel tank rust problems I preferred the TVIS coming in at a lower RPM, but I noticed that the AF ratio was more extreme than it should have been. It went from very lean to very rich and during part throttle was all over the place. I concluded that maybe it was due to different injectors (and it may be too), but have since learned that the TPS's are different for for the early, mid and late cars. The way the AF's were rising and falling in an extreme manner was definitely in reaction to the movement of the TPS. I am just keen to experiment.

[jimi]

Jimi, Do you have enough information to check which TPS is partnered with which ECU ?

Possibly, I'll investigate and get back to you tonight ( I'm nightshift :-? )

[Evo4Jon]

And also which part number for injectors please.
I have found that the rom package in the 070 is the same as the rom package in the 140ecu but with a different set of maps

I have an willem eeprom reader somewhere so I will try and set it up to take a look at the code.
This is a Supra one: http://svn.assembla.com/svn/7M_TCCS/D151801-3920/

Addition (Edit)
Just been researching this and it's somewhat out of my league... However, I think it might be interesting to understand the differences between the 3 ecu's and why Toyota did what they did. I also think that this research will give insight into what conditions must be met before the likes of Greddy piggy back ECU's can assist the factory ECU.

It might be that it works only on Mk1a setup due to higher injector impedance or maybe the mk1b with a resistor to increase the overall resistance or maybe a MK1a ecu with Mk1b injectors TPS and resistor pack to prevent the ECU from drawing too much current.

I have a suspicion that Toyota went from Saturated injectors to peak/hold type.... I think the Greddy would work best on saturation type. If someone can dig out a few square mk1a injector connectors and alternative mk1a TPS connector, I can then try all of these scenarios out, but I need to know what TPS belongs to which injectors and which ECU so that the standard map is right in the first instance. I have already bought a test solenoid resistor which I can mod to add resistance for emanage or short out if I install Mk1a injectors.

Any help anyone can bring to this would be greatly appreciated and it could serve many people if I can suss the best combination and then publish my findings

[jimi]

I used various UK VIN numbers that I have and cross checked using the ToyoDIY online EPC and a copy of the EPC I have on my PC, here's what I got. Obviously I can't guarantee this is 100% correct, having said that the 2 EPC's agree with each other.


ONLINE EPC (Toyodiy)

Using a UK 1985 VIN number:
ECU = 89661-17030
TPS = 89452-28010

Using a UK 1986/7 VIN:
ECU = 89661-17070
TPS = 89452-20070

Using a UK 1988 VIN:
ECU = 89661-17140
TPS = 89452-12040 (DENSO) & 89452-12050 (AISIN)

Using a UK 1989 VIN:
ECU = 89661-17140
TPS = 89452-12050 (AISIN)



OFFLINE EPC (on my PC)

Using a UK 1985 VIN:
ECU = 89661-17030
TPS = 89452-28010

Using a UK 1986/7 VIN:
ECU = 89661-17070
TPS = 89452-20070

Using a UK 1988 VIN:
ECU = 89661-17140
TPS = 89452-12040 & 89452-12050

Using a UK 1989 VIN:
ECU = 89661-17140
TPS = 89452-12050

I'll check the injector numbers and add them to the list when I get a chance.

[jimi]

Revised list with injectors plus I've added 1984, 1986 & 1987 VIN's


ONLINE EPC (Toyodiy)

Using a UK 1984 VIN number:
ECU = 89661-17030
TPS = 89452-28010
Injector = 23209-16010

Using a UK 1985 VIN number:
ECU = 89661-17030
TPS = 89452-28010
Injector = 23209-16010

Using a UK 1986 VIN:
ECU = 89661-17070
TPS = 89452-20070
Injector = 23209-16010

Using a UK 1987 VIN:
ECU = 89661-17070
TPS = 89452-20070
Injector = 23209-16090

Using a UK 1988 VIN number:
ECU = 89661-17140
TPS = 89452-12040 (DENSO) & 89452-12050 (AISIN)
Injector = 23209-16070

Using a UK 1989 VIN:
ECU = 89661-17140
TPS = 89452-12050 (AISIN)
Injector = 23209-16070


OFFLINE EPC (on my PC)

Using a UK 1984 VIN number: (JT1C0AW1100020000)
ECU = 89661-17030
TPS = 89452-28010
Injector = 23209-16010

Using a UK 1985 VIN number: (JT1C0AW1100044082)
ECU = 89661-17030
TPS = 89452-28010
Injector = 23209-16010

Using a UK 1986 VIN: (JT1C0AW1100094705)
ECU = 89661-17070
TPS = 89452-20070
Injector = 23209-16010

Using a UK 1987 VIN: (JT1C0AW110124102)
ECU = 89661-17070
TPS = 89452-20070
Injector = 23209-16090

Using a 1988 VIN number:
ECU = 89661-17140
TPS = 89452-12040 & 89452-12050
Injector = 23209-16070

Using a UK 1989 VIN:
ECU = 89661-17140
TPS = 89452-12050
Injector = 23209-16070

Also another small piece of info I dug out of my records (IIRC it came from Jeremy Ross)



89661-17030 (small case size ECU) as fitted to the mk1a MR2
89661-17070 (regular case size) as per fitted to crossover mk1b
89661-17140 (regular case size) as per fitted to later mk1b

The mixture screw wiring is different on the later 1b ECU (89661-17140)
so if you tried running a 17070 ECU in it then the mixture screw wouldn't work because it's wired to the wrong ECU pin and the ECU would default the mixture setting to mid point.

I have tried briefly running all three ECU types in a later mk1b and they all 'work' in that the car could be driven but as Paul says there are differences that mean that it isn't wise to run the wrong ECU type.

[Evo4Jon]

Great info Thanks very much Jimi !
:D

[Evo4Jon]

Just looking at the 1987 ECU ending 17070 and noticed that it doesn't have the pin called FPU - Fuel Pressure VSV. This controlls the vacuum to the fuel pressure regulator during certain running conditions.
3981

ON the 17070 ECU instead of the FPU pin it has one called BF.

I have looked in all the pdf's I have here and can't see what the BF pin is ?

Any ideas ??

EDIT** I have found that BF is injector +B.
http://i233.photobucket.com/albums/ee263/damo101/ecupioutstoyotaman.jpg~original
I take it then that on the 1987 model the injectors get their voltage feed from the ECU whereas later models fed it from main relay ?

Is this correct ?

[Evo4Jon]

on the earlier cars does the vacuum line go straight into the throttle body / plenum without going through an electrically operated VSV valve ?

[jimi]

No, the 1a has a injector relay feeds the injectors via a 10A fuse. See page 5 relay B on the Electrical manual I linked to.
What manual is that picture from and are you sure it applies to the AW11 ? because I can't find it (FI 72) in any of the AW11 manuals I have.
Regarding the vacuum lines, on the intake plenum there's a black plastic insert with 2 vacuum ports, on the 1a one of them is connected to a hard line bolted to the side of of the intake plenum which goes to the MAP sensor and I'm pretty sure the other goes to the FPR. On a 1b there are two hard lines, one to the MAP sensor and the other to the FPR VSV

1a

http://www.mr2mk1club.com/images/imported/2011/02/Chris20Worrral-1.jpg

1b

http://www.mr2mk1club.com/images/imported/2017/01/Jimi-1.jpg

[Evo4Jon]

Thanks Jimmy. The ECU image above is of an aw11 w/o af meter on page 91 of the 4age engine pdf. The ae92 ECU is the only other ecu pin out I could find with reference to BR as there is nothing in any of the AW11 manuals and yet I have the ECU right here in my hand?

When I look at the circuit board on the Aw11 17070 ecu, the pin that showed a green/bl wire going to the VSV labelled FPR (on the 17140 ecu) shows the print BR instead and if I look at the circuit board, it tracks on the board back to the centre pin of a large power transistor. This transistor sits next to the one connected to #10 and #20. Looking at other circuit diagrams I can see that on the AE92 the wire that feeds to the injectors carrying 12v (bat voltage) splits off prior to the Solenoid Resistor and connects to the ECU through the BR terminal and the Transistor on the board must help to drive the injectors. The 1987 cars with red injectors are low ohms too like the pink ones - both of which run the resistor.

When I run my 17070 ECU I will need to feed the ECU BR pin with a +Bat voltage wire with the same earth as the injectors to avoid any potential differences which may cause a delay in timing (I think)

As for the info on the Fuel pressure reg vacuum pipes this is a great help in confirming what I thought happened on earlier cars. But what does the VSV on the vacuum line do ?? (I here you ask) well it does this:
Here is the story on the valve direct from Toyota:

"Fuel Pressure Control. The ECU sends signals to the fuel pressure regulator VSV to increase fuel pressure based on intake air temperature, coolant temperature and starting signal. By this system, engine restartability is maintained when the engine is hot. When restarting a hot engine, the ECU increases the fuel pressure above the normal level to reduce the fuel tendency to percolate. This helps restarting and also maintains the engine idle stability. The controlled fuel pressure is 21.2lb/in2."

"Operation. When the coolant temperature switch is ON (above 221*F) or higher, if the engine is cranked, the ECU turns on the VSV. As the VSV goes on, atmospheric air is introduced into the diagram [sic] chamber of the pressure regulator and the valve closes the passage. The fuel pressure becomes higher than the fuel pressure under normal driving condition by the amount of the intake manifold vacuum only. Even after the engine is started, the VSV remains on for several seconds."


SO IN SUMMARY:

In order to run the 17070 ECU on a later car which has a 17140 fitted the fuel press reg vacuum pipe needs connecting directly to plenum vacuum source and on the ECU, the FPU wire (Green/Bl line) needs cutting and a feed attaching to supply the ECU with voltage +12v from just before the resistor pack. You need to fit red injectors 23209-16090 and change the Throttle position sensor to 89452-20070. Then change the plug to a square connector

I was trying to find the exact spec of the Red Injectors part number 23209-16090 but it was tough going. Then I read on a 4age forum that there was an alternate Toyota part number of 23250-16090.

I have not concluded exact spec of the Red injector but I think (based on stuff I have read) that it may be 192cc / 2.3 Ohms and single output ?

Would you concur Jimi ?

[jimi]

Based on the drawings and what you have found inside the 17070 ECU your summary sounds correct, however until someone actually tries it there's no way to be 100% sure. I'll see if I can dig up any more info on the red injectors, I've seen a list of injectors and specs somewhere, just have to find it.

[Evo4Jon]

Cheers Jimi!

[Sweetpea]

Looking at other circuit diagrams I can see that on the AE92 the wire that feeds to the injectors carrying 12v (bat voltage) splits off prior to the Solenoid Resistor and connects to the ECU through the BR terminal and the Transistor on the board must help to drive the injectors.

Sorry chaps, I'm not fully understanding that.
My understanding is that the injectors have +12 volts (via a dropper resistor AKA Resistor Solenoid) on one side and are switched to ground on the other side by the ECU. So an extra feed of raw 12V to the ECU on BR terminal can't be helping fire the injectors. You'd need 'more ground' for that. Or have I missed something?

James

[Evo4Jon]

Have a look here:
http://club4ag.com/tech-data/tech-specs/4a-ge-16v-japan-ae86-ecu-pin-identification/

Pin 10 Is BF and the wire colour is Yellow. The description says Power from Run position to ECU and main injectors

If you open up a 17070 the pin 10 is also marked BF.

Do you concur with my findings ?

I think the extra 12 Volts is to feed the injector circuitry in some otherway - maybe to power the extra power transistor to share the load or to stabilise the PWM circuit??? I am guessing. I wish Jeremy Ross hadn't disappeared off the face of the earth ! I can only conclude that he must have passed away to have been so passionate and no longer posting anywhere in the net :(

[jimi]

The extra feed may allow more current to flow as it's bypassing the resistors (which I think are there to limit the current)
Haven't managed to get any more info on the red injectors .. yet. Did find this via the EPC

http://www.mr2mk1club.com/images/imported/2017/01/1a20injectors-1.jpg

[Evo4Jon]

interestingly, that link I posted above shows the AE86 ECU probably for a bluetop with TVIS - same as the earlier MR2's. My Mum used to have an AE86 (corolla Coupe 1984 model) and when I was about 20 I used to borrow it alot. That engine was SO rev happy. It used to charge to the red line so freely, I was always hitting the rev limiter. I just want my MR2 to feel a bit closer to my AE86 experiences

[Sweetpea]

Sorry, was going to reply yesterday but spent the night trying to find what the BF terminal was for...

So - I agree that you need to connect the BF terminal to the positive feed to the injectors just after the 'fail safe' relay.

I did find this...
"For fail safe starting, you may also need to give power to injectors (Yellow wire found on 10Pin plug, Pin 10 (BF)) by joining a wire into the yellow wire and giving it 12V on iginition"
...here
http://www.ae86drivingclub.com.au/forums/showthread.php/22625-HOW-TO-4AGE-into-ADM-AE86-AE71-Wiring-guide
Which might be worth a read if you haven't seen it.

Personally I'm just not convinced that BF has anything to do with the injectors apart from pinching power from them.



The extra feed may allow more current to flow as it's bypassing the resistors (which I think are there to limit the current)

The resistor is indeed there to limit, or rather reduce the current in the injectors. Or, looking at the other side of the same coin, reducing the voltage across the injectors.
But the BF terminal can't be there to bypass the resistor because as far as I can see the 17070 ECU was used with high impedance injectors and no resistor. I searched the 'net all last night and couldn't see what BF was for. Probably doesn't really matter. Just wire it up and go for it!

[Evo4Jon]

I think the red injectors on the mk1b crossover are low impedance with the resistor pack. I say this because i recall reading a post where someone ran their mk1b on both 17070 and 17140 ecus ( as I have done) but they then tried an earlier 17030 ecu and when they revved it past 3000 rpm a fuse blew and the engine cut. I concluded that the mk1a must have high imoedance injectors and the 17030 could not take the current from trying to run a mk1b with low impedance injectors

Thanks for the extra info Sweatpea ☺

[Sweetpea]

Just when I thought I was getting the hang of it...

So I've got an engine manual that shows an ECU with a BF connection but no injector resistor pack. In fairness I think it was for a Corolla and who knows which model ECU it was.
And also Jimi's part numbers in post 24 show the 17070 ECU with the early injectors - and presumably no resistor.

Maybe the 17070 could drive either type but the 17030 couldn't. But then I'm sure Jeremy Ross said (in his "lifting the lid" article) he'd run all 3 ECUs on a MK1b car with no problem...

This'd all be a lot easier if Toyota put the part number of the ECU on the wiring diagrams.

James

[jimi]

Part of the problem (in figuring it out) is that I can't find a 1987 diagram to confirm the presence (or lack) of a resistor pack. Perhaps someone who has 1987 could check their ECU number and whether the resitor pack is present. Also reread Jeremy's article and found this

As mentioned in a previous article the wiring for the mixture screw appears different for the various mk1 types. The 89661-17140 mk1b uses a different ECU input pin number for the mixture screw. Although I don't have access to the other mk1 types (to look at the wiring) it appears that the 89661-17030 and 89661-17070 ECUs use a different input pin. This means that the ECUs are not 100% interchangeable and I would guess the wiring looms will differ in this respect too. If I put a 17030 or 17070 ECU in my 17140 mk1b then the mixture screw will not work. The car runs OK otherwise.
and this

I fitted an mk1a 89661-17030 ECU to my t 'test' mk1b,

[Evo4Jon]

I found the post I had read a while back:
http://imoc.co.uk/forums/viewtopic.php?t=45590&sid=601efa9f937e18673f734f6c98bfba47

"Hi Ian,yep tried a mk1a ECU in a MK1b, it wil idle perfectly, but as soon as you open the throttle some rather large fuses blow [Shocked]"

Jimi I have just re-read your table and realised that the injectors 16010 substitute is 16090.

This does mean that the grey injectors 16010 (mk1a) and the 16090 Red are the Mk1b Xover are interchangable which suggests that the 17070 is indeed expecting to see high impedance injectors !

Hmmmm

I have ordered a set of Red injectors and grey ones so all will be revealed !

[jimi]

Jeremy posted further down that same thread


I tried an early shaped ECU (don't know what code) that ran my '89 model fine for a short run up the road. Maybe it was a change over year ECU.

Yup, Both of my mk1s are 1989 with 89661-17140 ECUs.

I have run the mk1a (89661-17030) and early mk1b (89661-17070) ECUs in my mk1b (and also the 1985/6 AE86 ECUs) without problems.

However. the mixture screw wiring is different so with a mk1a ECU (or a 89661-17070 ECU) in your 89661-17140 mk1b the mixture screw ceases to have any effect.

Also, the MAP sensor (and injectors?) are different types apparently.

For these reasons you should stick to the correct ECU for your car.


What about the differences in the engine mk1a vs mk1b? The ribs on the engine are different and so are some of the internals. Also my red mk1b was one of the last made and it has a slightly different cam cover to my blue 1989 mk1b. (different as in colours of the cam lettering)


The mk1a ECU (89661-17030) has a bigger 3D ignition map. It is mapped up to 7200rpm. :)

The mk1b (89661-17070) is only mapped to 5200rpm for the ignition. :cry:

The later mk1b (89661-17140) is only mapped to 5600rpm for the ignition. :(

[Evo4Jon]

Jimi. Can you check if map sensors are showing different part numbers in relation to the 17030 / 17070 and 17140 ecus please?

[jimi]

There were only 2 MAP sensors used on AW11 MK1 MR2's world wide
MAP = 89421-17020 until Frame number AW11 0091542 then changed to MAP = 89420-17020
Change was mid Aug 1986
Edit
Did a bit more checking and noticed that the MAP sensor change date (and frame number) coincides with the ECU change from the 89661-17030 ECU to the 89661-17070 ECU

[Evo4Jon]

I have ordered:
MAP = 89421-17020
1 set of 4 grey injectors (1985) 23209-16010
1 set of 4 red injectors (1987) 23209-16090
1 throttle position sensor
TPS = 89452-20070 (1987)
1× throttle position sensor connector
(Square early type)
1 x ECU = 89661-17030 (1985) ( Ihave 17070 and 17140 already)
1x spare solenoid resistor to modify (short out or add load) for use with high impedance injectors or if I run older ECU on newer injectors.

I wanted to get a mk1a TPS = 89452-28010 so I could look at the calibration. It wont fit to later Throttle body though

[Sweetpea]

Yes, I noticed that they changed injectors on the 17070 ECU. That means that the later injectors are either high impedance or low impedance with a dropper resistor.

My current working theory is that any ECU can run any injector. But you must use the resistor if you use the low impedance ones. God knows what it does to the injector timing though. My reason for thinking this (apart from Jeremy doing it) is that the difference in current isn't that massive between the two systems. The power transistors are going to be well over spec just for reliability. In fact I'd guess that the real problem isn't the forward current when they are turned on, it's coping with the back EMF when you try and turn them off again.

The blown fuses story is interesting. I suspect something else was going on there. Or they got it wrong and it was a MK1b ECU in a MK1a car. I can see that might cause blown fuses.
The 1b ECU is trying to control fuel pressure by grounding the FPU pin. But if it's in an early car that wire is connected to the battery via the INJ fuse. So the poor ECU tries to short the battery. :o

James

[Evo4Jon]

I can see how a mk1b crossover using the 17070 could toast a 17140 via that BF terminal. Neil Jones will be sending out my bits on monday so I will be able to compare pinouts on the 17030 and also the resistances of injectors and map sensor under different states of vacuum.

Whats the 2nd electrical box under the mk1a 17030 ecu? Do you know?

[jimi]

Have a look here:
http://club4ag.com/tech-data/tech-specs/4a-ge-16v-japan-ae86-ecu-pin-identification/

Pin 10 Is BF and the wire colour is Yellow. The description says Power from Run position to ECU and main injectors

If you open up a 17070 the pin 10 is also marked BF.


You need to be careful when referring to links like the above, looks to me like the way they have numbered the pins is wrong i.e. not the same as the standard Mr T method, although the location of the pins is correct the pin number is wrong. The pic below will illustrate the difference this is looking at the ECU

http://www.mr2mk1club.com/images/imported/2017/01/ECU20N20connections-1.jpg

This could be very misleading if you refer to the pin numbers not the actual locations.

[Evo4Jon]

Good point well made Jimi.

The bottom right pin is the one I have added a bullet connector to on my X-over loom ready to break the circuit and connect the +ve from the injectors so all it good.
On the later Mk1b which uses the 17140 ECU the colour of the wire is Green with a black line which goes to the VSV.

I have a 2nd Solenoid resistor pack which I have modified so that I can bypass it and using a damaged ECU I cut out the socket and soldered the plugs from an old loom onto the pins. Then I heat shrinked where the pins were soldered and then used black hot glue to prevent flex on the joints. I will used this as my loom changer so my original wiring stays intact

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(If the engine runs well and I intend to keep any of the setups permanently, I will then properly solder any joints and not use Bullet connectors!)

[Evo4Jon]

Also
Whats the 2nd electrical box under the mk1a 17030 ecu? Do you know?

3986

[Sweetpea]

I don't know, but an exploded diagram says...

http://www.mr2mk1club.com/images/imported/2017/01/31621428434_5bf4d79738_z-1.jpg

"Relay, Fan". I take that to mean it's the control box for the fan in the side of the engine bay.
Problem is, I have no idea which model or year the diagrams are for.

[jimi]

Yes, it's the engine bay cooling fan computer (relay) That's the 1a position, on the 1b the ECU is mounted in the middle of the bulkhead. That diagram looks like it's for the 1b.
Bullet connectors are fine in that environment just don't use scotchloks!!! :sick:

[Evo4Jon]

I soldered the bullet connectors instead of crimping which I thought was more reliable also :geek:

[Sweetpea]

Actually crimping is fine too so long as you use a good ratchet crimper and not those useless stamped 'pair of pliers' things that most people have.
What you shouldn't do is tin the end of the wire with solder and then put it in the crimp and crimp it. Or use it under a screw terminal for that matter. Over time the solder squishes out and they tend to come loose.
To be fair IDCs (Insulation Displacement Connector - what a Scotchlok is) are also fine but you need to be very careful with wire sizes and you need a proper tool to punch them down. Apart from the fact that they are really ugly, Scotchloks real down fall is people. They use wire that's the wrong size, crimp them with a pair of pliers, run high currents through them and hide them in the rain and spray under the car. Any wonder they fail.

Anyway, I'll shut up and go do some work now!

[Evo4Jon]

I properly soldered my bullets and replaced the insulation afterwards ;)

[Evo4Jon]

I got the injectors today

I am rather fed up as the impedance of both the reds and the greys 23250-16010 are 2.0 Ohms ! I read that they are interchangable, so I suspect that both are 182cc.

So I am no further to running a piggy back ecu unless I add resistors in addition to the resistor pack - which will compromise the running of the standard ECU as I suspect it will mess up the pulse width info and make the system too high impedance for Peak and hold accuracy.

In summary then it appears that ALL UK MR2 mk1's run low impedance injectors and unless the resistor pack is different on earlier cars then the ECU's all work with a load of 2ohms.

I am now the proud owner of 8 injectors that are the the same impedance as my current pinks ones but flow less ! :(

Further more I tried to program my Greddy eManage ECU and it wont connect to my PC. Its dead... PC doesn't even acknowledge the connection is active and there is no power from the USB cable which suggests that its been damaged by previous owner of the unit. So Its being returned! ... This unraveling of facts is like running up a treacle mountain !

Most of the info about injector impedance on the internet seems guess work and a case of "I read somewhere" I even read posts by Paul Woods who stated that the earlier injectors were high impedance, but this appears not to be the case - unless there is another injector out there that runs on a MK1a and its got a different part number.

[Sweetpea]

All low impedance... I have to say I hadn't expected that.

My car (built late 85) is in storage at the moment and I won't see it for a few weeks. But when I'm next over that way I'll measure mine and let you know.

I was reading up about peak hold stuff. I rather suspect that all the mk1s are running saturated even though they are low impedance injectors. You'd have to get a scope on the ecu to be sure either way. I just doubt they were that sophisticated back then. Apart from which I'd imagine that any advantage in fuel metering you get from peak / hold would be lost because you are batch firing them and the fuel is sitting in the intake runners waiting for the valve to open.

James

[Evo4Jon]

Thanks James !... Its nice to know that someone is reading and thinking this one through with me (not forgetting Jimi too!)

at least I will be able to run my 89 on the earlier injectors along with the TPS and my BF +VE feed to see how the 2 compare. Its also good to read your thoughts on the Peak and hold and I must say that as the EFI is so crude I think you may well have a valid point.

One of the reasons I want to do this is so that I experience and can check the differences between revised MR2 versions. My Later engine is a stronger version than the earlier engines - being the red top, but I do recall the drop in performance of the 89/90> models due to the change in fuelling around this time when unleaded fuel became the standard on our forecourts. Toyota sent out many service bulletins about the use of unleaded fuel and the fact that it burnt hotter / more readily in the cylinders and had no lubricating properties. Some of the the demo vehicles I drove when working at Toyota around that time seemed a little under-powered as I recall. The other Salesman and I really noticed the drop in power on Carina and Corolla models especially. The 12 Valve 1.3 GL Corolla was a really zippy car as an 1987 E. It stayed nippy and free revving until late 89 - 1990 facelift version. Externally the changes were subtle and consisted of different Wheel trims, a new front grille and the 3 hoops logo. The interior trim went from a rope-effect tweedy material to a suede / velour. The Stereo was upgraded to one with rounded buttons and better speakers. We thought that the changes were a real improvement until we drove it ! The car was really slow and it felt tight - like it couldn't rev. The engine had a carburetor and to help with emissions a damper was fitted so that the engine produced less hydrocarbons on the over-run. We drove a few and realised that the modifications for the higher emissions restrictions had spoiled a great little car.

I want to understand whether the later MR2's were detuned a little by retarding the ignition at higher rpm in order to produce lower emissions.

[Sweetpea]

It's just a subject I'm interested in.
I remember the first EFI car I owned. A '92 Carina Exec. It was a total transformation over cars with carbs. It just behaved, year after year after year. You just knew that carbs were finished. Makes you wonder how it works and why it's better...

Anyway, I hadn't twigged that the mk1b happened around the same time as unleaded fuel. This drop in power in Corollas an Carinas - was that in the carb models or the injected ones? Or both?

[Evo4Jon]

Was your Carina the Carina E Exec or the Carina II Exec ? The Exec was a 2.0 litre engine - but not the same as the Celica 2.0L though.

The Carina II from 88- 92 was 16 valve fuel injection - as was the Camry, Celica, MR2, Supra etc. The only carb models were Corolla 1.3 GL, Starlet 1.0, lite-ace and Hi-ace. The 1990-92 Carina 2's were def slower. I had a few demo cars. In late 89 / 1990 they face-lifted the whole range to coincide with the new logo. The cars that were noticeably slower were the ones with the new logo. The Carina XL came out as a lower spec Fleet version (to compete with the Nissan Bluebird and Vauxhall / Ford models). The later cars were not as rev happy as the earlier GL's. I had a Carina XL Match demo also which was green metallic https://www.flickr.com/photos/mr_gav/6911512090/in/photostream/

In the late 80's, the workshop were being bombarded with info about emissions, fines, legislation and these new fangled devices called Catalytic convertors ! The 4AGE engine was doomed as it was considered too polluting. The Japanese also were mindful of our changing fuel. In the early 1980's, we got engines with same exact spec as the Japanese cars. The UK fuel was considered similar. The USA got the lower powered versions because of the emissions and the lower octane unleaded fuel. For the UK, Toyota just changed clocks from Kms to Miles and there were import restrictions limiting numbers of cars imported. Emissions was a huge deal in the USA from 1970's but it didn't come here til the 90's. In the UK We never had the 4AGE in any other vehicles other than Corolla GT Coupe, Corolla GTi (FWD) and the MR2 Mk1. The Carina II 1.6 Engine was the 4AFE which was more refined and smoother but a bit flat. http://www.abload.de/img/foto12080mjvj.jpg

The Mk1 MR2 was never face lifted like the others, but was replaced with the MK2 MR2 and at the time I never drove many MR2's, but the later corolla GTi's weren't quite as quick as the earlier ones. I knew this well because my Mum had the Corolla GT coupe (1984) and there was a Corolla Gti FWD on as a demo most of the time and I took customers out in it and borrowed it a few times. The AE82 has crazy Torque steer and the AE92 less so. The AE86 was just ace. Revvy and exciting. I borrowed my Mums once and went to Stretford Arndale Centre in the pouring rain. I recall pulling away from a set of Pelican crossings and booting it.... I ended up facing the opposite direction and all the cars behind me had to slow to a stop and let me turn around ! LOL (I Was 20 and it was the 1988)

[Sweetpea]

I'll read that properly later. It's noisy here at work...
Mine was a Carina II exec with a 3S-FE. I quite liked it. Not exciting but it did what I needed for years. You're right though. It was flat and didn't rev. There wasn't much point in red lining it 'cos it was well past its best before you got there. I always thought the '16 valve' sticker inside was a nice reminder because you'd never tell from driving it.
Didn't know the early ones were better.
It was replaced with an IS200 which was the complete opposite. It'd run into the limiter with no warning if you weren't watching and it felt like you'd hit a wall.

[Sweetpea]

Time for more speculation! 'cos it's easier to sit here and speculate than go and fix my leaky distributer...

So, in the late 80s Toyota were scared about the introduction of unleaded and they 'backed off' the ECUs. Thinking about this, what would they have actually done?
If you are worried about combustion chamber temps you aren't going to reduce fueling, if anything you'd make it richer. (Not that I fully believe the old story that lean mixtures run hot and rich ones run cold.) So, I reckon you'd retard the ignition. Especially at high revs where it's more likely to suffer detonation (pinking). And that would cause it to be less rev happy and feel flat.
I believe one of the early techniques for a rev limiter was just to keep retarding the ignition until the engine wasn't producing any power and the driver had to change up. I don't suppose you can do that with catalytic converters so they just cut the fuel off.

Two things I believe Jeremy Ross said (although I'd struggle to find the quotes)...
First he suspected that the 17070 was intended for a different territory. So perhaps Toyota, suddenly afraid of fuel quality in the UK, went and rummaged in the parts bin and found a suitable ECU that would do the job until they did the proper facelift later. Hence we get the 'crossover' cars.
Second, I'm sure he said that the early 17030 ECU had a fully 3d mapped ignition all the way to the red line. But the later two ECUs were only fully mapped to 4500 revs (or something like that). After which what are you doing? My guess would be that you ignore the revs and pay attention to the MAP sensor. But I'd ned to think about that...

I think it's a shame Jeremy disappeared too. I think he'd be a fascinating chap to get in the pub for an evening.

James

[jimi]

mmmmhhh bear in mind that Japan had fully phased out leaded petrol by 1986 so they already had a MK1 ECU (and engine) capable of running OK on unleaded before it's introduction into the UK.

[Evo4Jon]

mmmmhhh bear in mind that Japan had fully phased out leaded petrol by 1986 so they already had a MK1 ECU (and engine) capable of running OK on unleaded before it's introduction into the UK.

But the grade of the Unleaded was different I think. Japan have had 100RON fuel since the mid 80's and we had 95RON. However there is another standard that Japan use called PON where 100PON = our 95RON. its all speculation and we will never truly know what went on but my MR2 feels like the ignition timing is too retarded at the top end because it is less rev happy and runs richer than I think it should from 6500 onwards. When I fitted the 17070 ECU last summer I felt my car was much more like the AE86 I remembered driving, but the fuelling was all over the place! This was due to my injectors being 200cc where as the ECU was expecting 182cc. Maybe also the TPS had a different response curve, But I aim to test this over the coming weeks as I now have a TPS from the mk1b X-over which ran the 17070 ECU. I also have a map sensor with the different plug so I will test this using a multimeter and a vacuum tester I have.

Its nice to know the exact differences between the versions! I love finding out all the hidden stuff which is made easier with both your help .

Thanks James and Jimi !

[Evo4Jon]

I think it's a shame Jeremy disappeared too. I think he'd be a fascinating chap to get in the pub for an evening.

I seconds that !!!!.. Such an interesting and clever guy

[Evo4Jon]

Just opened up a 17030 ECU to have nosy. I can report that it has the BF connector like the 17070. Also all the pins are the same as the 17140 except the BF pin.

It would seem that the 17030 and the 17070 should be interchangeable without modifications and both ECU's should run the cars with no discernible difference - if the pin labels are anything to go by.

Can anyone confirm that a 17070 and 17030 run the car without differences ?

Note : The Grey and Red injectors of the mk1a and the mk1b X-over are both low impedance (2ohms) and that the power transistors are the same in the 030 as the are in the 070 so nothing is more heavy duty in in either ECU.

Just out of interest, here is a pic of the inside of the larger 17140 ECU I have removed the sockets from (this is going in the bin at some point) and the 17030 which I intend to run in my car.
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[Simon5264]

Hi Guys does anyone have a schematic of the Mk1b 89661-17140 Late UK) ECU. I have looked everywhere but can't find one to match my set up

[jimi]

Depends what your looking for, you won't get a complete schematic for the ECU, Toyota never made them available, you can get schematics showing the pinouts for the ECU.
I have a scanned pdf copy the 1987 (May) Toyota 4F, 4A-GE engine manual I've uploaded it to my website and you can download it using this link CLICKY (http://myweb.tiscali.co.uk/jlawson2/4A-GEManual.pdf) I'll leave the link active for a day or so to allow you to download it. Once you have it go to page FI-31 for the pinouts.
N.B.
The manual covers several variations of the 4F, 4A-GE make sure any sections you are looking at refer to the AW11 version W/O (without) Air Flow Meter. There are differences and it's very easy to get mislead by looking at the wrong variation ;)