Here is the story... car ran fine so I parked it for the night and took out the diagnostic cable (Steve Ruse cable) because he accidently forgot to put in the 10K ohm resistor. I wanted to put in my own so I wont have to jump the resister myself all the time, no big deal just something I wanted to do. So I reconnected everything and left it for the night. Yesterday morning the car started (with the fan running) and ran really rough for about 5 seconds, then died.... it cranks and wants to run, but only for 5 seconds. So I try to check the codes and the SES light stays on all the time!!! even with the paper clip it... doesn't flash anything at all never mind a code.. just stays lit. I disconnected the computer and the light went out like it is supposed to. I figure it is a bad computer so I buy another remanufactured one and same thing!!!! The only code I got was about 2 weeks ago and it was a code 42... something about the distributor. But, that was only once... similar condiditons, ran really rough then stalled, gave me a code, then started and ran fine!!
What do I do now, I already bought a new computer for $100, and gave them my old one. I tried to check the sensors and relays to see if they fried the computer... but wouldn't you think the computer would be able to protect itself somehow instead of just dropping dead? I checked all of the fuses, I have fuel pressure, the starter works, and I check the connections from the ALDL to the computer... what gives!!
I just swapped the TPI from a carb and everything was working fine for about 2 or 3 weeks so I really doubt it would be a crossed wire, if it was wouldn't the computer last another 2 or 3 weeks before it died too! I had to reuse the original cal pack and chip, well the one that I modified. But the computer should still give a code even if I take out the chip and go into limp home right? It seems like the computer just died and cursed all that follow!



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'86 TA, T-tops, T-5, 3.73, 4 wheel disks 350, compucam 2040, performer intake,SLP Headers, 3" race magnum muffler, 1.6 Comp rockers, Ripper shifter, perf. friction pads, Hypertech ignition, Earls brake hoses, Hotchkis springs, Tokico Illumina 5 adjustable shocks and struts, Lakewood panhard and trailing arms
14.50@ 97 with carb... now converted to TPI

 

IIRC, the error codes (DTCs), backup fuel tables, and injector and other I/O control are part of the PROM, not the ECM firmware. the engine should not operate without a PROM. If you are not getting the POST flash of the MIL when you first turn on the ignition, you may have a PROM or I/O wiring problem. I realize that the engine ran for a few weeks, but some of the wiring may have changed since then, whether you intended it or not.

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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

Well, you lost me with some of that. But if I translate that you are saying that if the prom is bad the engine wont run... well I agree with that. But shouldn't I at least get a working SES light? As far as the misterious jumping wires... I wont completely rule them out however it is highly unlikely.

 

Some one has to have another idea, I'm begging for any thoughts at all!

 

Anyone!

 

A failed or missing PROM will prevent the MIL lamp from operating correctly. The ECM firmware tests the memory address range of the PROM and does a simple I/O test when the circuit is powered up (ignition on). If the ECM doesn't pass this self-diagnostic test, the MIL won't flash once like it is supposed to. It may stay on constantly, or not turn on at all.

Make sure the PROM is inserted fully and correctly (it should be correct if the engine ran for a few weeks). You might also want to check the grounds at the ECM.

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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

Thanks for the help Vader, I finaly got the car to run tonight, I took out the ignition module and had it test then put it back in, it fired and ran, not well, but it ran. The computer is still giving me fits, so I'll have to try the prom next, after I check the grounds some more.