SWGSSSlacker

Hello all,

I used to be able to run the code tests on my mustang but just recently the only codes I can pull are the KOEO codes and not the KOER. When my Actron scanner is put into test mode (KOER) it doesn't elevate the RPMS anymore and I'll get code 13 (can not raise RPMS for test) a few seconds after I start the test. I'm going to look into replacing the EEC IV relay but haven't yet, I have uncovered and inspected the ECU though....found out it's remanufactured with absolutely no FOMOCO information on it. The engine in the car will also die out of the blue, it'll be running along and bam...dead. I have to turn the key completely off and restart the car only for it to happen again. I talked to some fellas at a local tuning shop today and they mentioned that it could possibly be the ECU. They mentioned that they have dealt with problems similar to mine from previous customers stating that particular control areas will sometimes fail in the ECU and cause running issues.

Anything sound familiar to anyone here?

The fuel pump is coming on and pumping (39lbs with vacuum line off reg and 32ish when vacuum is hooked back up). I have replaced the fuel pump relay.
I have replaced the FP reg., coil, TPS, IAC, PiP sensor, ICM, plugs, wires, cap and rotor, tested another MAF meter in my cold air intake.

SWGSSSlacker

I realize it isn't really a question but I am looking for information.

1. Can no longer perform KOER tests!
2. Engine dies out of the blue for no apparent reason!
3. Have replaced everything electrical with the exception of the EEC relay and the ECU.
4. Replaced the fuel pump relay because it was a stored code in the KOEO test.

I'm at my wits end with this car to be honest. I'm almost ready to pour 5 gallons of gas on it and watch it burn. I've owned it for 8 months and have worked on it for 6 of those months.

88 orangepeel notch

Possibly, when my computer took a crap, I had similar troubles, but I could always pull codes with mine. Do you have any way of swapping in another to verify? Otherwise its kinda an expensive guess to buy another reman ECU.

I'm not the most knowledgeable about this, but I thought I remember a thread a while ago about an ECU not allowing codes to be read, it did turn out to be a bad ECU.

dawson1112

Its able to read KOEO, but not the KOER codes then its just a matter of figuring out why the self diagnostics is unable to control the RPMs during self test.

If you replaced the IAC and cleaned the throttle body good, you could either have purchased a faulty IAC or you have a bad connection for it.

SWGSSSlacker

The car tested fine and then all the sudden it no longer did. I have the same IAC on it now that I did when I was able to EEC test it. I did not unplug the IAC valve at any time nor did I mess with the connector. I may be wrong but it stopped testing around the same time the engine would just shut itself off. So, again I may be wrong but those two happening at the same time makes me think the ECU crapped out.

SWGSSSlacker

Also...

Yes it will read KOEO but won't COMPLETELY read KOER due to the fact that it can't elevate the engine RPMS to perform the EEC test. So I guess it'll read KOER codes because I do get a code 13 (can not raise engine rpm) but unless the ECU/motor do what they're supposed to do I do not get to run complete EEC tests.

I did remove the ECU from the car and opened and inspected it, it didn't smell burnt but I did find some corrosion on the circuit board. I tried brushing the corrosion off with a plastic bristled brush but after it was reassembled and re-installed it made no difference, the car still idled like hammered sh*t and still had the super rough miss in between 1000-2000 rpms.

Everything electrical on the car is new except for the ECU and alternator (13.4 volts when the car is running).
The new parts might be 4-6 months old but they are still new to me, I've only put about 5k miles on the car since
the engine replacement.

SWGSSSlacker

No, No replacement to test here but I did order a new one from Rockauto.com.
It was $227.00 for it but $95.00 of it is a core charge so $132.00 isn't to bad.

It's not a FOMOCO either it's a http://www.rockauto.com/catalog/rafr...ktemplate=true

Part # 784352

At this point I don't care if Walmart makes an ECU for my car I just hope something fixes it soon.

88 orangepeel notch

I bought my reman'd A9L from Auto zone for $98, but that was probably 5 yrs ago now. And no core needed. Has been perfect so far.

Good luck

SWGSSSlacker

Sorry for the delay in responding but I'm still at square one.

After the ECU replacement, re-check of TPS voltage, re-check of timing and firing order the car will still die out of the blue while running. Once it does die it will not start until I turn the key totally off and restart the motor. If I try to start the car without turning the key all the way to the off position it will simply turn over and not start. It's like it has to reset something with the key off before it'll start, run a while and shut off again. The car will also still not complete an EEC test, my Actron scanner will give me a code 12 (engine RPMS can not be raised above normal idle). I mentioned earlier that everything electrical except the EEC relay and the alternator is new. I'm at the end of my knowledge base here and I'm ready to set the car ablaze, of course I won't do that but it has crossed my mind.

Any more suggestions to be had?

Thanks

SWGSSSlacker

Update:

Replaced what I believed to be the EEC relay (right next to the ECU). I started the engine, it ran for 30 seconds and died out of the blue. I didn't attempt to troubleshoot any further, shut the hood, locked the doors and said fudge it for now. Fuel pump primes and fuel pressure remains constant during these instances.

Grrrrr.......