PFF - Pennock's Fiero Forum, PDA Edition

Question about ECU (Page 1/2)

mlopezbe

OCT 25, 12:48 PM

Hello, my 1986 Fiero GT AT has a cold failure and the engine stops if it does not accelerate. The fuel-air mixture is not correct. It has all new sensors, new injectors, the computer does not display an error code. We no longer know what to check.
Before I continue spending money, I would like to test if the problem is with the ECU. My mechanic has a Chevrolet Lumina APV 3.1 ECU that works properly. Externally it is the same, but I don't know if the internal connections match. The idea is to know with certainty if it is the same one that the Pontiac has, so we can test it in the car and see if the fault continues or not. Does anyone know if this test can be done? Thank you!

olejoedad

OCT 25, 01:49 PM

Most likely it will not work, and could possibly damage your friends ECU.

Vintage-Nut

OCT 25, 02:07 PM

You can test your ECM

I had 'weird problems' with an ECM in a different vehicle, so I sent my computer to ECU Exchange for testing.

They found a bad power supply which created distortion on the reference and system voltages.

The grand total was around $140

I bet that you will find a ECM service like ECU Exchange in Argentina

If not, this is the service I used in USA:

ECU Exchage
https://www.theecuexchange.com/
https://www.theecuexchange.com/contact-us
Or call (561) 408-6375

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

lou_dias

OCT 25, 02:43 PM

Sounds more like your IAC is not working...

Dennis LaGrua

OCT 25, 03:39 PM

As Joe said, do not use another GM ECM not designed for your year Fiero. I don't mean to be harsh but why do so many Fiero owners do not bother to invest in a multi-meter, fuel pressure gauge, ignition tester and a scanner. My suggestion to you is measure your fuel pressure . It should be about 40-43 PSI .

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

mlopezbe

OCT 25, 04:09 PM

quote

Originally posted by olejoedad:

Most likely it will not work, and could possibly damage your friends ECU.

Thanks, I won't do the test.

mlopezbe

OCT 25, 04:11 PM

quote

Originally posted by lou_dias:

Sounds more like your IAC is not working...

Thanks, I'll check this out.

mlopezbe

OCT 25, 04:16 PM

quote

Originally posted by Dennis LaGrua:

As Joe said, do not use another GM ECM not designed for your year Fiero. I don't mean to be harsh but why do so many Fiero owners do not bother to invest in a multi-meter, fuel pressure gauge, ignition tester and a scanner. My suggestion to you is measure your fuel pressure . It should be about 40-43 PSI .

Thanks, my mechanic has the elements you say. I'm not sure about the fuel pressure gauge. I'm going to consult with him and tell him the correct value it should have. The main problem is that in my country there is absolutely nothing available for the fiero, neither spare parts nor tools. There are very few mechanics who are interested in receiving this car to inspect it and that is why it is very difficult to diagnose the fault. Thanks again!

mlopezbe

OCT 25, 04:21 PM

quote

Originally posted by Vintage-Nut:

You can test your ECM

I had 'weird problems' with an ECM in a different vehicle, so I sent my computer to ECU Exchange for testing.

They found a bad power supply which created distortion on the reference and system voltages.

The grand total was around $140

I bet that you will find a ECM service like ECU Exchange in Argentina

If not, this is the service I used in USA:

ECU Exchage
https://www.theecuexchange.com/
https://www.theecuexchange.com/contact-us
Or call (561) 408-6375

Thank you. I still haven't found someone who can check the ECU and tell me if it works well or not, that's why we had thought about replacing it with a similar one to see how the car behaves. But I have already ruled out this option and I will continue looking for someone who can review it. Thanks again!

Dennis LaGrua

OCT 28, 01:47 AM

One thing that I did not mention is that ECM's can and do fail. Only a dealer with a test jig can test and determine if it is good but often but not always the ECM will set a code that indicates the unit is not working. If you post the ECM part number here a number of dealers here who sell parts can probably give you a quote sell you one and ship it to you.