HELP!!! PCM relay keeps tripping!!!

[Larry Phillips]

Help!! I'm having an issue with my ST- After about 2-3 minutes of run time, she shuts off as if I turned the key to off. There's no bad indication, no CEL, no lamp test, no fuel pump, only the normal blinking THEFT light. I figured out the PCM relay is tripping, but I can't figure out why. After a minute, it switches back and I can start the engine, just to have it happen again.



The ammeter is slow to come up to normal indication, and it moves when the headlights are turned on. I'm currently thinking either the alternator or the voltage regulator maybe going out, but I need a second opinion. Also, the cruise control died about a week or two ago. At this point, I can't even make it out of the driveway.

 

[Todd Z]

Larry,



It could be the alternator or battery, IT does sound electrical...



Do you have a chip on the computer ??? From what i remember you have the xcal ??



The best thing is to test the amps being drawn by the pcm.... Is there another relay you can swap it with ???



The other thing could be a bad connection or ground around the relay or the PCM...



Todd Z

 

[Tom Schindler]

First things first, I would shy away from the battery being the problem. An engine will run without a battery. Same with the alternator. An engine will run until the battery goes dead.



Is there a PCM relay? You could check the relay. Maybe there is an issue with it.



I would also revert back to the stock program before I go anywhere.



Check the battery cables. Maybe you have two simple issues that make it hard to diagnose. (i.e. your alternator or voltage regulator is bad and your battery cable is loose, corroded, bad, etc.) That can cause the following condition...when you start your vehicle, it fires right up. After a minute or so, the battery cable rattles and the engine dies.



I had a SLIGHT problem like that earlier this year. I am one of those people that just crank my engine enough to get it started. I barely hit the starter. Just enough to get it to turn over.



When I would do it, it would spit & sputter and then die. If I kept cranking on it, it would start fine. One day I pop the hood and notice one of my cables were loose. Tightened it up and never had an issue since.







Tom

 

[Larry Phillips]

Thanks for the help! It turned out to be an ignition wire.

 

[Tom Schindler]

Ignition wire like a Spark Plug wire?





Tom

 

[Larry Phillips]

No, an ignition wire off of the ignition switch under the dash. One (green/purple) that I clipped when I was working out the kinks way back when I put in the starter button. I had put an insulated spade terminal on it after I cut it and realized I didn't need to. That connector came unplugged somehow.

 

[Tom Schindler]

OK. In other words, something you did/did not do.





Tom

 

[Larry Phillips]

Something I did came unplugged unexpectedly. Probably from road vibration and bumps. (lowered truck)