04 Electrical Gremlins

[rkeil1]

At my wits end with my wife’s 04 Tahoe

3 months ago it died on her far away from home. Got it towed home. Both INJ fuses were blown. As soon as I put new ones in and hit the key on they would blow. Found the ground on the back of the head passenger side to be barely hanging on. Cut splice and boom back in business.

Last Monday, I get the call it died again. This time it had “reduced engine power” and went full limp mode. Couldn’t go over 2 mph. Code U0107. Got it towed home and cleared the code. Ran fine after that. Couldn’t get it to do it again until 2 days ago.

Died again, no codes, just two blown inj fuses. Towed it home. Replaced fuses and it started. 2 minutes later it blew those fuses again. Took the top cover off and immediately started inspecting wiring. Couldn’t find anything exposed or damaged. Played around with the whole harness and walked away to grab another adult beverage. As I walked away it died again. Replaced the fuses again and now I can’t get the problem to happen again. Don’t want to drive it down the road and risk having to pay a 4th tow.

What is your guys thoughts? Any common spots for the wiring to go bad to cause a short to ground and blow these fuses? I’m over this thing. Shame too cause it’s in decent shape and only has 190k on it and she loves it. I have pulled the fuse box up and don’t see anything chewed or eaten. I added the “big 3 or 4 ground mod” ground from battery to throttle module then to body ground then to motor ground. I have tugged squished and pulled on the wiring coming off the throttle body. Nothing. I can’t make it happen. Seems like it just happens randomly. Short of replacing the whole harness I am not sure of what to do.

 

[Fless]

Go to www.charm.li and select your vehicle. In the electrical diagrams, find those ignition fuses and see what they power. Trace.

If they go to the ECM (hey, even if they don't) remove the two connectors on the ECM and look for pin fitment and water migration into the connector pins. If there's moisture or green crusties, clean the connections and install new connector gaskets.

When you get to your vehicle on the Charm site, follow the tree below, using the Wiring Diagram Index to get to the correct diagram:

 

[PNWYukon]

From another forum: If its blowing a fuse it has a short to ground somewhere.
Another forum: IF YOU HAVE CHECKED FOR A SHORT THEN MOST LIKELY YOU HAVE A BAD INJECTOR. YOU CAN UNPLUG ONE INJECTOR AT A TIME UNTIL IT STOPS BLOWING FUSES OR YOU CAN TAKE IT TO A REPUTABLE TECH WHO CAN HOOK IT UP TO A SCAN TOOL AND IT SHOULD SHOW THE BAD INJECTOR.

 

[rkeil1]

From another forum: If its blowing a fuse it has a short to ground somewhere.
Another forum: IF YOU HAVE CHECKED FOR A SHORT THEN MOST LIKELY YOU HAVE A BAD INJECTOR. YOU CAN UNPLUG ONE INJECTOR AT A TIME UNTIL IT STOPS BLOWING FUSES OR YOU CAN TAKE IT TO A REPUTABLE TECH WHO CAN HOOK IT UP TO A SCAN TOOL AND IT SHOULD SHOW THE

I wish I could make the fuses keep popping but they don’t. I’ve wiggled and moved everything trying to make it happen but I can’t make it happen again. Seems very odd. If I could make them pop again this would be easier

 

[rockola1971]

From another forum: If its blowing a fuse it has a short to ground somewhere.
Another forum: IF YOU HAVE CHECKED FOR A SHORT THEN MOST LIKELY YOU HAVE A BAD INJECTOR. YOU CAN UNPLUG ONE INJECTOR AT A TIME UNTIL IT STOPS BLOWING FUSES OR YOU CAN TAKE IT TO A REPUTABLE TECH WHO CAN HOOK IT UP TO A SCAN TOOL AND IT SHOULD SHOW THE BAD INJECTOR.

Not all true. A short to ground is not the only electrical problem to cause a fuse to open up. The real cause is excessive current draw exceeding the fuse rating and a loads resistance lowering can cause a fuse to open and loose, dirty, corroded and missing grounds will cause excessive current draw as well.

 

[rockola1971]

I wish I could make the fuses keep popping but they don’t. I’ve wiggled and moved everything trying to make it happen but I can’t make it happen again. Seems very odd. If I could make them pop again this would be easier

Find you some auto reset or manual reset circuit breakers to take the place of the bowing fuses. Amazon or Ebay is your source. You may have some wires melted together in the wiring harness that was caused by the broken ground causing excessive current draw. Need to get an ohmeter on the injector wiring harness and take measurements to ground during wire wiggle tests. May have to open up the split loom tubing to get a better look and handle on the wiring harness.

 

[Fless]

I misread which fuses you're dealing with. Here's an example (again, be sure to select your vehicle) of how the injector wiring runs:

Engine Controls Diagram 9 — 2004 Chevrolet Tahoe 2WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2004 Chevrolet Tahoe 2WD V8-5.3L VIN T.

charm.li

 

[rkeil1]

I guess I’ll have to start just following wires from that charm diagram. Since I can’t make the problem reciprocate its self I will have to look at each individual wire until I see something out of the ordinary. Electrical issues are a pain, personally I would rather be wrenching on something mechanical lol. Thanks for the help. I will keep reporting back. Someone else has had to have come across this before.