'01 sierra z71 starting problem

degradedsanity

I,m having an issue where the truck doesn't even try to turn over most the time but once in a while it will start no problem. engine runs fine every time it starts, just doesn't engage starter. Any one have ideas other than loose connection?

imidazol97

@degradedsanity said:
I,m having an issue where the truck doesn't even try to turn over most the time but once in a while it will start no problem. engine runs fine every time it starts, just doesn't engage starter. Any one have ideas other than loose connection?

Do the dash lights, including the security light, operate normally when you turn the key to ON when it doesn't start? Or does it flash after rotating the key.

4 If that part indicates the key transponder is being read correctly, then I'd suggest the starter. There are a couple of ways to troubleshoot this. If you have more than one person, locate the starter body and tap on it solidly with a small hammer--something to give a good vibration--WHILE someone holds the key to CRANK when the thing doesn't react at all. The solenoid connection inside can not make contact and the vibration will cause it to make contact and crank the engine, sometimes. Replace starter.

3 If that doesn't work and you have a voltmeter, identify the small connection on the starter that is not the heavy red wire from the battery nor the heavy black cable. This is the one from the crank signal from the ignition switch power.

2 Test that for 12 volts while the key is held to CRANK. Clip one lead onto the small terminal. Be sure the other voltmeter lead is connected to a good ground like the battery negative black terminal. If you don't get a 12.6 v current there when in CRANK, then you've got a circuit problem or a problem with the system that reads the key transponder and allows cranking and fuel injectors to work--if it's designed like my 03 leSabre.

1 Also check the ground cables from the battery and their connections. Some GMs have more than one besides a heavy one to the engine. Also check the positive cables for corrosion, Especially if you have multiple cables at the battery on top of each other. There can be corrosion between them that is fickle about making connection through the lead spacer.

How's the battery? If you have more than one vehicle with similar batteries, substitute for the one in the truck to see if it affects your start problem.

Check the cables at both ends. And cut into the plastic covering near the battery to be sure the copper inside has not been eaten away by acid seep from the side terminal batteries.

Good luck.