1995 tahoe backfires with headlights on
I have a 1995 tahoe 350 tbi with 280k miles. I just replaced
the coil, pickup coil, icm, cap, rotor, plugs wires and plugs.
And now it starts and runs fine until I turn my headlights on.
Then it stumbles and backfires but only when driving. it
won't do it at idle. Sometimes it will even stall out. I've
checked all my grounds that I could find and checked
alternator and everything seems to be in order. I've noticed
when I turn the head lights on my volt gauge on the dash
drops from 14 to 12 but alternator is still pushing 14. Now
I'm at a dead end so someone please help :(
Plus my tach has been jumping around alot lately I noticed also
Congrats on the 280,000 miles, that's an achievement. This vehicle owes you nothing. If it's in great physical shape, it's probably worth fixing and you obviously have an electrical problem. If you cannot solve this, take it to a professional. The fact that you have almost 300,000 miles on the original engine and transmission says a lot about the integrity of these cars and the way you maintained it.
Im really hurting on money right now so I'd like to try and figure it out myself if possible. Just don't have any idea where to begin :/
Definitely sounds like an alternator problem. Although I've never seen one do what you're describing. Put the alternator under load without the headlights. Turn on the rear defogger, which draws about as much power as the headlights, and the defroster on high blower at the same time. But leave the headlights off. See if it acts up. If not it's a problem with the headlights. If so, it's a problem with the alternator or possibly the battery connections. That'd be my best guess. HTH. -Jim
It didn't do it wile the defroster and blower were on. Does the headlights have a ground somewhere between the switch on the dash and the headlights somewhere that could be causing this? I was thinking about adding a speaker system to my truck but after all this crap has happened I've been having second thoughts..
It's definitely the headlight circuit then. Sounds like it's somehow upsetting the ignition system. Are these original type headlights or is this an upgrade of some kind. I'd check the ground connections for the headlights and the ignition system. HTH. -Jim
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