99 chevy tahoe wont start unless its jumped

Amanda Rushing · October 10, 2015

I have a 99 chevy tahoe and we have replaced the starter, alternator, and battery but it will not start unless i get it jumped. The engine cranks but wont fire. We have even replaced the battery cables and the mega fuse. My husband and father in law cannot figure out why it will not start and im about ready to junk it. Please help

barry G · October 10, 2015

something needing too much to get going?

relays, bad grounds. is it clean under the hood? back by gas tank?

even fuel pump needs battery, how old is it?

ifixedit · October 11, 2015

Let me make sure I have this straight. So you're saying it will crank on its own (without jumping it) and it won't start (it just cranks over), but when you jump it, it will start? If so, that doesn't even make sense. Please elaborate.

Amanda Rushing · October 11, 2015

Let me make sure I have this straight. So you're saying it will crank on its own (without jumping it) and it won't start (it just cranks over), but when you jump it, it will start? If so, that doesn't even make sense. Please elaborate.

Amanda Rushing · October 11, 2015

Exactly nothing about this make sense. We have talked to everyone we can abouy this and no one can figure out why it wont start. it has all the components to start but it won't. Fuel pump is only a couple years old.

j-ten-ner · October 11, 2015

When you jump the truck do you connect both cables to the battery?

Or do you connect the ground cable to the engine?

so long

j-ten-ner

ifixedit · October 12, 2015

This may provide a clue but I don't know the answer to this question so will ask: Can anyone here tell us if this is a ground to run, or is it a ground to shut off ignition? Or is it more a certain component that needs to be grounded in order for it to run? It seems by jumping it you're completing the circuit that's missing on its own, I'd be looking over the possible grounds for a problem.

j-ten-ner · October 12, 2015

When they connect the ground (jumper-)cable to the body (eg. engine) on the Tahoe and it fires up, then it is likely that the ground cable from the battery to the body has a bad contact.

But when they hook up both jump-cables to the battery and it fires up, then I don't know.

so long

j-ten-ner

Edit: Have you tried another battery?

ifixedit · October 12, 2015

What happens if you jump it and it starts and then you disconnect the jumper cables? Does it keep running?

00Silverado4x4 · October 13, 2015

As already said, you are losing a ground somewhere that is being provided by the jumper cables. Double check all fuses that have anything to do with ignition and also double check the wiring on the starter to ensure everything is reconnected correctly.

ifixedit · October 15, 2015

To add to the above recommendation, I'd also be checking all the various body grounds to the frame, engine strap ground, etc. You can generally find all the ground location illustrations by googling the year make and model / body grounds / images. They are typically listed as grounds G10, G04, etc., etc. There's generally quite a few of them connected to various points on the frame, on the radiator support, the firewall and so on. I know on my 03, if I disconnect the ground located under the drivers side door on the frame the truck dies but will crank over, just won't run.