Would any check engine light keep the engine from going into closed loop?
Seams I am having problems with the 94. I can't get a scan tool to work and thought that I could just figure the thing out by checking everything. What I get is if I clear the coads the engine will start and run for about 10 sec and then the check engine light will come on. If I don't clear it again the Check engine light will come on at start up and stay on.
What codes will retard the timing? The power is low and has that sound of bad timing, but after 3000 or so RPM it will take off like new. We tested the ECM as a OBD II, but after looking at past posts I think I have a OBD I, with the OBD II, conector??? (is this true for 94?) How do I test this thing?
Thought that I had this thing figured out last week because my engine fan was running after cold start up. But after finding the problem only being a bad compressor head switch and repaired that I'm back to nothing!!
Does some one have a list of codes and what effect it will cause?? Like I said the engine sounds as if the timing is way-slow. The only mod is a custom chip that the engine ran great on before this. I do have the computer on the floor to check sensor OMes.
Thanks

You need an OBD1 scantool with a 16pin connector.

Looks like the PCM is looking for a critical parameter within that window of time, and not finding it. You need to get it scanned, there'* really no other way.

The engine will run in limp mode missing most of the sensors, but I don't know of any that will kill it after 10 seconds unless the idle is just dropping too low?

BTW, fans should run if the AC is in Auto (compressor on).

Thanks for the quick answers. Is this tool one that I can get at a good price??
The fans were running with-out the A/C on and a cold engine. I tested the red-wht wire going too the head psi switch and found it open. unplugged it from the compressor and found that the wire had conection,.
I think I was misleading on the 10 sec deal, the car never dies just the Check engine light on after 10sec of running and the low power issue. What you say about the ECM looking for a reading from one of the sensors sounds right to me. I now need to find the one that it is looking for. LOL Is this a test that Auto Zone can test? Do they usualy have the tools for this?
Thanks again,

Autozone won't touch a 94/95 hybrid PCM. You have an OBD1 PCM with OBD 2 codes and connector.

Put your location in your profile. We may have a scantool living near you.

east Iowa,
That'* bad news on Auto Zone. What would I look for if I were to buy a simple one. When Auto Zone put the tester on last week they didn't look as if they knew what they were doing. But then again I didn't know what I had. This car only has 51,000 miles It sould be back in top shape after if get this issue behind me.

Regarding location of someone with an OBD1 scan tool - Ilive in the Auburn-Opelika area of East Alabama off I-85 (1 hour East of Montgomery, AL). If there are any listees in this area who have a scan tool for my 94SE, I'sd sure oike to make contact. The local Pontiac dealer wants $45 just to scan codes.

Thanks,

Mike

There'* a scantool registry in Techinfo. It needs to be slightly updated, but that'* it so far.

You need to find a place that uses the Actron Super Scanner CP9145 with a 94 GM adapter or the CP9150 Super Kit. I've had luck with Advance Auto using this tool. For some reason, my local Auto Zones use the tool just below this even though they carry the Super on the shelf for $395 or so. I'm tempted to "buy and borrow" it so I can pull my codes on the road and get my money back.