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Electrical Problem-eng surges, tach needle freaks out, shift up light blinks randomly

Discussion in 'GM Powertrain' started by DeathByNissan55, Aug 24, 2012.

  1. DeathByNissan55

    DeathByNissan55 New Member

    I have a 1994 chevy k1500 4x4 ext cab with the original factory 5 speed manual and a TBI 350 from a 1991 chevy caprice.
    What is the usual cause for the problems described below?:

    The starter works nicely, but the engine is just not wanting to start easily. It will turn over eventually, but it takes a couple cranks and my foot almost to the floor on the accelerator for it to work. It had a low idle before and sometimes it stalls out before this problem occurred, but now it literally wants to die. When you give it throttle, it feels as if I'm not getting combustion on every stroke as if some strokes werent firing. The aftermarket Tach needle is going all over the place and the "shift up" light is blinking on and off in a random fashion as if there were an electrical problem(ie bad connection). If I dont try to keep it running, it clunks out.

    Someone told me ignition control module, but that doesnt sound right at all cuz how would that affect the tach and shift light. I think its an ECU problem or something along those lines. Or it could be a combo of a bad ground and bad ignition control module.

    Edit: Actually the ignition control module might make sense because when i took the air cleaner assembly off and looked at the injectors spray as my dad was trying to keep the truck alive, it wasnt cutting the spray ever...so yea.
    Last edited by a moderator: Aug 25, 2012
  2. Kady

    Kady Rockstar GMTC Chick 100 Posts

    The ignition control module failed in my 96 suburban after installing a remote starter and had the same symptoms... After installing the remote start, when the truck was started with the remote start, it wouldn't shift out of first gear. Didn't realize it was only when I used the remote, so I changed the trans fluid and filter, and eventually figure out it was the ignition module when I would remote start it... The guy who installed the started did something (not sure if he replaced it, or bypassed it) but it fixed that problem... But then after, only once in a while silly things would happen to the dash lights, and exterior lights, and the truck wouldn't stay running unless I kept the gas pinned after it turned over. Then sometimes it would still die. The few times I got it to keep running, the idle would be choppy and run from about 4-500, when it would normally be about 750... Also, about your tach light, mine was an Auto, but when I would shift from park to drive, the truck would just die right out... Before I sold the truck, we figured it out that it was the ignition control module, but the new buyer was a friend of mine, and said he'd take care of it himself.
  3. DeathByNissan55

    DeathByNissan55 New Member

    So I replaced the ECM with the correct one and it came with a new PROM that was also the correct one for the truck.....didnt fix the problem totally. However, you can tell that it runs a lil bit better and it doesnt always just die by itself anymore. Also found out when replacing ECM that there was an animal nest in my dash right on top of the blow motor, bunch of the wires were nibbled on. Fixed those and they didnt change anything.

    So it leads me to believe its something to do with a sensor. What kind of sensor would cause too much fuel to be added and to make the tach/shift up light freak out? Also, I determined that somewhere in the chassis electrical, the parking light circuit is tied into the brake light circuit. Cuz when I have the key off and hit the brake pedal, the dash lights turn on, the parking lights and brake lights turn on, and the annoying bell goes off in unison with whenever i hit the brake pedal. Also, when i just turn on the parking lights, the brakes will come on too. So where would be the most likely place that would happen? The hitch mount area?

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