ds76

Hi Guys,

I have a ploblem with my 2002 Z71. It's got a 5.3 L engine and an extended cab. I was idling at a gas station and it died. It would turn over fine, but wouldn't start. I noticed that the gas gauge showed empty and I knew the tank was nearly full. I started checking fuses and found one blown in the fuse box under the hood. I replaced it and the gas gauge showed full again, but the truck still wouldn't start. After trying it a few times, the same fuse blew again and the gas gauge showed empty again. I'm pretty sure I have a short somewhere and I'll have to trace it down, but I'm hoping somebody here may have seen this happen before and can give me a place to start. Thanks for any help,

David

MDTAHOE

You need to see what you are lacking, fuel or spark then go from there. I would suspect fuel. What is the fuse labeled?

ds76

Hi MDTAHOE,

Thanks for the reply. I put a fuel pressure gauge on the fuel rail and got no pressure at all while cranking the starter. I replaced the fuse and still got no pressure. The fuse that's blowing is labeled ECM B. Is it my fuel pump, or is it the computer?
Thanks for your help,
David

ds76

I went and bought an Actron OBD II reader. With the blowing fuse replaced, it says 0 codes and with the fuse removed, it says NO LINK. I'm at a loss and feeling pretty frustrated.

David

MDTAHOE

Unplug the fuel pump connector and see if the fuse blows. I highly suspect a blow up pump.

ds76

I'm not sure where to unplug the pump. Will I have to drop the fuel tank to get to the plug? The fuse doesn't blow now, so will unplugging it now tell me anything? I can't hear the fuel pump running when the key is turned on or during cranking. I even used a stethoscope and couldn't hear anything. I have a Haynes manual that shows how to remove the fuel tank. Once again, thanks for your help.
David

MDTAHOE

ECM B does have the fuel pump on it.

ds76

Well, I syphoned out all the gas I could get out of it this afternoon and I guess I'll drag out the transmission jack and try to drop the fuel tank tomorrow afternoon. Maybe once I get the tank dropped, I'll find some short or broken wire I can fix and not have to buy a new fuel pump. Those things are expensive! I appreciate the help. Wish me luck.

ds76

I dropped the tank and pulled the fuel pump. I couldn't find anything obviously wrong and I didn't know what the resistance should be on the pump motor leads. It read 0.7 ohms - not open windings and not a dead short, so it really didn't tell me anything. I decided to go ahead and buy a new fuel pump anyway and I'm glad I did. I put it in and remounted the tank, which was not as tough a job as I was afraid it was going to be. The truck is running great now. in fact it was idling a little rough before, so maybe the pump had been going out for a while. Thinking back, it did die at a red light about a month ago and wouldn't start for a minute or two. Do these fuel pumps quit intermitantly when they're on the way out? Thanks to MDTAHOE for the useful info,
David

LARIDERS

what was the millage on it when the pump went out?