Ecu help

[Watthefucklike]

Hi all could you please help, i have to replace my ecu, i suspect the wrong one may have been fitted by previous owner, i have a 1987 325 mtech 1 so pre facelift i guess, it has abs and the 3 pin idle valve, im guessing it should be motronic 1.3, but am not sure and require advice and part numbers before buying. Cheers all.

[Cloggy Saint]

This may help https://www.e30zone.net/e30wiki/index.p ... e=Motronic

[Watthefucklike]

I cant work it out, im thinking i might need the '073' ?

[Watthefucklike]

Actually i just checked that one doesn't have 3 rows of pins that i need.

[onthames]

0261 200 073
I think

[Watthefucklike]

O73 is the wrong one, i need 3 rows of pins

[Watthefucklike]

The main reason im asking is i need the one that works with the 3 pin idle control valve

[Watthefucklike]

Does anybody know which ecu operates a 3 pin idc??

[Watthefucklike]

Ok i figured it out, i can use any later ecu so im going to go for the 380

[Speedtouch]

You may be better off with a 173 (you could also use 172 or 179 with a chip-change), as the later 380/381 have extra diodes in the idle control circuit that are prone to blowing, causing a rough idle.

It is odd though, since a 1987 Tech 1 Sport should have the earlier M1.0 073 ECU, so either someones changed the wiring loom, ECU, etc., or fitted a complete later replacement engine and electrics...

[Watthefucklike]

You may be better off with a 173 (you could also use 172 or 179 with a chip-change), as the later 380/381 have extra diodes in the idle control circuit that are prone to blowing, causing a rough idle.

It is odd though, since a 1987 Tech 1 Sport should have the earlier M1.0 073 ECU, so either someones changed the wiring loom, ECU, etc., or fitted a complete later replacement engine and electrics...

I know right? i better check the engine numbers, i currently have a 173, and its the idle control output on pin 4 that i currently have the problem with, as its only putting out 3.9v as an earth against battery voltage, as apposed to 10v that the hanes manual suggests at ignition. Also, Is my 87 m tech 1 supposed to have abs? Theres a pump there, but i know for a fact it doesnt work. Also i have found that an abs wire has been cut inside the c101 plug...

[Watthefucklike]

Yep its a later engine, numbers dont match, im sure it wouldn't have put me off buying still. Bummer though.

[flybynite]

There is a wiring pitfall when swapping an early HC engine and late LC engine that often results in a fire ( I have one that had that in the past) It involves the wiring to/from the C101

I can't find the old post and the person that knows this off the top of his head goes AWOL this time of year, I can't remember the detail but the secret is in the pre/post facelift wiring differences of the C101. It might be relevant to your problem.

Any reason you thought it was clever to swear in the username?

[Watthefucklike]

Didnt even think about my username mate. Its normal to me and most others.

Any reason you chose to belittle me to make yourself feel better?

[flybynite]

Any reason you chose to belittle me to make yourself feel better?

Just think it's unnecessary that's all, but if it makes you feel good

[onthames]

Ladies

[Speedtouch]

Not all later engines were low compression; check the engine number, stamped on a raised section on the inlet side of the block just above the sump - if it's 25 6E, that's high comp, while 25 6K is low comp.

IIRC, ABS was an option on Tech 1/pre-facelift 6-pot e30s.

[biffer]

My July '87 sport came with an 073 ECU and ABS fitted, but that was about it- no power-steering, no electric windows/sunroof.

[Watthefucklike]

They've swapped it out for a 25 6E 2. So still high compression by the looks of it. Thats gunna devalue my car significantly right? Not having matching engine numbers? Or is it preferred to have an later ecu/sensor/engine and loom setup....

[twenty]

Its normal to me and most others.

Not in the part of the country I'm from ;)

Any reason you chose to belittle me to make yourself feel better?

He didn't. It's a perfectly valid observation.

[Speedtouch]

I would say in a way it's a desirable swap, since you now have the better Motronic 1.3 (more reliable, with better resolution, plus easier to 'chip' and get replacement parts for).

Only a purist and stickler for originality 'OEM homo' would be overly bothered about it.

I've heard some Tech 1 gurus saying the earlier management gives a more raw and 'edgy' feel to the driving experience, but then again you have the added potential problem of an additional crank sensor in the bellhousing to possibly go wrong, plus older wiring, etc.

[twenty]

I would say in a way it's a desirable swap, since you now have the better Motronic 1.3 (more reliable, with better resolution, plus easier to 'chip' and get replacement parts for).

Only a purist and stickler for originality 'OEM homo' would be overly bothered about it.

I've heard some Tech 1 gurus saying the earlier management gives a more raw and 'edgy' feel to the driving experience, but then again you have the added potential problem of an additional crank sensor in the bellhousing to possibly go wrong, plus older wiring, etc.

While on the subject, my pre facelift 325i auto cab has a 0261 200 380 ECU which I suspect was a replacement by a previous owner. According to the ECU wiki page it should be 0261 200 164 as it’s an auto?

Are there any difference between automatic and manual ECUs?

[flybynite]

While on the subject, my pre facelift 325i auto cab has a 0261 200 380 ECU which I suspect was a replacement by a previous owner. According to the ECU wiki page it should be 0261 200 164 as it’s an auto?
Are there any difference between automatic and manual ECUs?

Depends whether the 380 ecu has the pins for the Auto kickdown and Lockup. Does the car kickdown?

As you probably know 'prefacelift' does not mean much with convertibles as they kept the PFL well after the rest of the range. Yours at 1990 should have the mechanical/electricals of a FL car.

[twenty]

While on the subject, my pre facelift 325i auto cab has a 0261 200 380 ECU which I suspect was a replacement by a previous owner. According to the ECU wiki page it should be 0261 200 164 as it’s an auto?
Are there any difference between automatic and manual ECUs?

Depends whether the 380 ecu has the pins for the Auto kickdown and Lockup. Does the car kickdown?

As you probably know 'prefacelift' does not mean much with convertibles as they kept the PFL well after the rest of the range. Yours at 1990 should have the mechanical/electricals of a FL car.

This is where it gets a bit embarrassing. What’s a kickdown and how do I activate it?

[Watthefucklike]

Guys i am absolutely buzzing. Just bought a mint 2.7 engine with all ancillarys for £1000. Time for stroker build!

[twenty]

While on the subject, my pre facelift 325i auto cab has a 0261 200 380 ECU which I suspect was a replacement by a previous owner. According to the ECU wiki page it should be 0261 200 164 as it’s an auto?
Are there any difference between automatic and manual ECUs?

Depends whether the 380 ecu has the pins for the Auto kickdown and Lockup. Does the car kickdown?

As you probably know 'prefacelift' does not mean much with convertibles as they kept the PFL well after the rest of the range. Yours at 1990 should have the mechanical/electricals of a FL car.

This is where it gets a bit embarrassing. What’s a kickdown and how do I activate it?

Okay, so did some more research. According to the ETK, there are two DMEs that came for my car, part no 12141735364 and 12141748260, both are supposed to be 380 and Monotronic 1.3.

12141735364 is listed as Basic Control unit and 12141748260 as AT-Control unit which I assume means it’s for a car with automatic transmission?

Having looked at the ECU sticker on mine the part no is for the basic unit, so seems like I do have the basic unit.

[Watthefucklike]

On an auto car, the kickdown is usually on the throttle pedal. When you push the throttle all the way to the floor you should feel a button being pressed, (usually a switch under the pedal) which makes it drop a gear and use more of the gear before changing,
Thats how it usually works, but i dont know on an e30...

[BenHar]

On the standard (non switchable) automatic the kickdown is actuated by a cable from the throttle mechanism.

The button under the pedal is just there to give a clicking feedback when the pedal is pushed right down.

Ben

[Speedtouch]

Yes, the 380 (or 173) ECU should work fine in either manual or autos. I think some autos have a separate ECU.

Sounds like a result, getting the 2.7 - any pics?

[Watthefucklike]

Yeah its in good nick, still in the car atm

[twenty]

On the standard (non switchable) automatic the kickdown is actuated by a cable from the throttle mechanism.

The button under the pedal is just there to give a clicking feedback when the pedal is pushed right down.

Ben

I have a non switchable auto. There’s a button but as you say it’s not hooked up to anything.

[twenty]

Yes, the 380 (or 173) ECU should work fine in either manual or autos. I think some autos have a separate ECU.

Sounds like a result, getting the 2.7 - any pics?

Cool, thanks. Good to know. I think the extra ECU is for switchable auto which I don’t have.

[Speedtouch]

Looks like a nice engine in what appears to be a nice car (makes you wonder why they would separate them?), but it appears to be a standard 525e (eta), in which case, you'll need to change at least the cylinder head, possibly pistons also...

https://www.e30zone.net/e30wiki/index.p ... ding_a_2.7

[Watthefucklike]

Hes swapping something bigger into it. Sent me a video of the engine running its very smooth. Mine is a 325 sport so i got most the stuff i need to build the stroker. Just need an ecu now, cause mine is kaput.

[onthames]

Would have done the swap on a 325 but not a sport personally.