153 to 173 ECU

[325ix]

A few days ago I was getting a CEL after idling for about 20 secs. It would come on and stay on for a few restarts afterwards. I decided to put in the 173 ECU I have. It fixed the CEL, it no longer comes on. However, I now get an anti-lock brake light on the dash. Any ideas? This is in an 88ix.

[jlevie]

The DME has nothing to do with the ABS, that fault is a coincidental failure.

While the original DME could have been faulty, the CEL while idling is more likely to be a Lambda fault and caused by an aged O2 sensor and intake leaks. The useful life of an O2 sensor is 100k and it is a scheduled maintainance item. A smoke test is the only sure way to locate intake leaks at any of the possible locations.

[MR 325]

I am SO TIRED of seeing a smoke test suggested.

[b*saint]

jlevie is right tho. These cars are so old and crusty you can't rule out intake leaks.

[QUKBMER]

Use carb spray like the old days. Smoke testing is for late model 2000-up models.

[nando]

Use carb spray like the old days. Smoke testing is for late model 2000-up models.

what? :weak:

[nando]

actually, the ABS issue does have to do with the ECU (it's an ix thing).

you need to add a 1k resistor from pin 17 of the C101 connector, to ground.

[325ix]

Ok, thanks, I am going to say that since I don't get a CEL anymore, it was my Ecu that was bad. It went away. Thanks Nando.

[nando]

it could come back. it was in an old TSB on early ix's - what happens is the output from the ABS computer to the ECU can end up floating. Grounding it with a resistor still lets it work but you won't get the ABS fault anymore.

[325ix]

If it does, then I will look into it, but for now it is gone. I think my tps may be going bad, because it only does it on idle. Thanks for the info.

[b*saint]

Wouldnt the carb spray NOT work because your ICV is constantly modulating idle air? Ive never had the carb cleaner trick work on a car with a ICV.

[nando]

I don't know if the ICV is the reason, but i've never had the carb cleaner trick work on an M20 either.

[325ix]

It works after the icv. I think it may be the reason.

[BrooklynMW]

I had the opposite problem. I took out my 153 and installed a 173 w/ Bavauto chip. CEL went on after about 200 miles, and my mpg's dropped a few numbers. Put the 153 back in and car ran fine w/o any warning lights.

[325ix]

Weird, I think my ecu was the problem, but time will tell.