2004 auto coupe will not start

[jimbow]

I got some time to work on it this weekend and its not good.
No fuel pressure, finaly found the fuse - it was blown.
Replaced with 20A fuse, car started and I shut it off - the fuse blew again. put another 20A fuse in and while the wife started the car there was a nice bright flash as the fuse blew again. put a 30A in and same thing!

So has to be something in the circuit protected by the fuse.
Any obvious places that folks have seen issues?
Or is it time to find a half dozen people to help me load it on the trailer and take it to the mechanic?

[LLC5]

Originally Posted by jimbow

I got some time to work on it this weekend and its not good.
No fuel pressure, finaly found the fuse - it was blown.
Replaced with 20A fuse, car started and I shut it off - the fuse blew again. put another 20A fuse in and while the wife started the car there was a nice bright flash as the fuse blew again. put a 30A in and same thing!

So has to be something in the circuit protected by the fuse.
Any obvious places that folks have seen issues?
Or is it time to find a half dozen people to help me load it on the trailer and take it to the mechanic?

What is the exact name of the protected circuit on the fuse panel cover?

Do not install a 30A fuse in a 20A circuit or you may be following the smoke to the shorted area, and possibly buying a new harness. Never install a larger fuse in any circuit on a newer vehicle as the manufacturers have down sized wiring sizes to a point where the wires are barely able to handle to OEM fuse size as it comes from the factory.

[jimbow]

IIRC Fuel Pump is the fuse (may be abbreaviated)
Its next to the fuel pump relay

[LLC5]

Originally Posted by jimbow

IIRC Fuel Pump is the fuse (may be abbreaviated)
Its next to the fuel pump relay

Any aftermarket electrical accessories on the vehicle, or any vehicle damage in the past?

[jimbow]

Originally Posted by LLC5

Any aftermarket electrical accessories on the vehicle, or any vehicle damage in the past?

Nope, bone stock auto coupe.
Has had the front bumper cover replaced, but thats all the body damage.

[LLC5]

Originally Posted by jimbow

Nope, bone stock auto coupe.
Has had the front bumper cover replaced, but thats all the body damage.

I only have a 1998 FSM and I know your fuel system is different so it may not cross over perfectly. 1998 shows a dedicated #13 mini 20A fuel pump fuse with nothing else on the circuit, so a chafed/cut harness somewhere between the fuse panel and the fuel pump, or a bad pump or even the wiring to the pump on the sending unit could be the cause. You are lucky to have an active short as they are the easiest to diagnose. I would start by disconnecting the fuel pump at the tank and see if the short is gone. Good luck with it.

[jimbow]

Unfortunately the 04 has everything in the tank and the hookups are at the top of the tank. Which means "drop the tank" to work on this :(
I did pull the battery and tray out this weekend to inspect the wire bundles you can get to there. No observable issues.
When I get back from DC it will go on the trailer to the dealer. They have a master Corvette Mechanic that is very good, he has been working on Corvettes since the late 70's.

[jimbow]

Just a followup. By a suggestion from a racer its a common enough problem he was able to point me to a solution.
Behind the inner fender is where the body harness and the fuel pump wiring join together. Both sets of wires were rubbing against the "frame" metal there. A clean up, adding a bunch of electrical tape has eliminated the wires touching the frame. And its not blowing fuses and runs great.

[froggy47]

Originally Posted by jimbow

Just a followup. By a suggestion from a racer its a common enough problem he was able to point me to a solution.
Behind the inner fender is where the body harness and the fuel pump wiring join together. Both sets of wires were rubbing against the "frame" metal there. A clean up, adding a bunch of electrical tape has eliminated the wires touching the frame. And its not blowing fuses and runs great.

Which fender is this behind?

[ToolGuy]

Originally Posted by jimbow

Just a followup. By a suggestion from a racer its a common enough problem he was able to point me to a solution.
Behind the inner fender is where the body harness and the fuel pump wiring join together. Both sets of wires were rubbing against the "frame" metal there. A clean up, adding a bunch of electrical tape has eliminated the wires touching the frame. And its not blowing fuses and runs great.

Geez! What a great tip and glad you fixed it!

Never heard of this one myself.