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HELP! '03 Silverado Died!!!

Discussion in 'Chevy Trucks' started by northernnewbie, May 27, 2007.

  1. northernnewbie

    northernnewbie Member
    Messages: 31

    I was driving down the road and the SERVICE BRAKE light went off along with a warning bell, the engine cut off and I had to fight the steering wheel to get it to the side of the road as it ground to a halt. The key locked in the ignition and it won't turn over at all.

    I had it towed to my usual repair shop but they say they can't even access the PCM with their scanners. They tried the brakes and it worked fine. They started it by manually cranking it but it wouldn't run on its own.

    I went through the fuse box and found that the fuel pump fuse had blown. I replaced it and got all excited when it started up so sweet and strong...only to have it die as I gassed it in reverse to leave the repair shop.

    I'm thinking crankshaft position sensor...

    :help: :help:
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    If it blew the fuel pump fuse then either the pump is dying, or the main wiring harness to the rear of the truck is corroded or damaged somewhere (which would also explain the service brake warning). I'd first do some wiring diagnosis before replacing any hard parts.
  3. northernnewbie

    northernnewbie Member
    Messages: 31

    Now that explanation makes sense and I'd rather fix the fuel pump or the wiring rather than the CPS.

    Two tanks back I put in some Lucas Fuel cleaner after I swore I'd never use silly snake oil on my vehicles, but my buddy really wanted to see it help my fuel $$.


    If it ends up being the fuel system, then my buddy is never gonna hear the end of this:realmad:

    Thanks for the advice B&B, I'll follow up on that and have the fuel pump looked at and inspect the rear wiring.
  4. northernnewbie

    northernnewbie Member
    Messages: 31

    I checked the truck today and the battery is dead...which definitely points to a fault in the wiring.

    Tomorrow I can charge the battery and check a few things now that I've read up some.

    1. I'll see if the fuel pump relay is getting power. According to my repair manual the PCM cuts power to the fuel pump relay if the CPS fails to send a signal. If that relay is getting power it could still be CPS. I read that there was a problem with the CPS's on the '03's causing them to stall.

    2. With the battery charged and the key in the on position, listen for the fuel pump to engage....and also make sure it cuts off properly

    3. I'll also see if the garage can check the fuel pressure.

    4. With the truck up on a lift I can get a better look at the wiring.
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Keep us posted on what you find newbie or if you need any info, just ask. You are correct that the PCM will cut power to the FP relay if it doesn't see a signal from the CPS while the engine is cranking but the pump should still run when you first turn the key on as you know. The blown FP fuse is the clue that you definitely have a short either in the wiring or inside the pump itself as I already mentioned.
  6. northernnewbie

    northernnewbie Member
    Messages: 31

    I visually inspected every bit of the wiring down there, from the fuse box right to the fuel tank and then some. The inline fuse on my trailer brake wiring looked corroded and had a pebble wedged inside it. So thats one weak link thats been dealt with.

    Still need to check all the ground connections, there had to be a half dozen ground wires coming out of that main rear wiring harness. :dizzy:

    Bought a fuel filter that I'll snap on when the fuel pump gets looked at. My repair shop is wicked busy and two guys are on vacation this week so no one had looked at it yet. Thinking I might just go to Autozone and get a fuel pressure gauge on loan.

    B&B, thanks for your continued support, you've definitely steered me in the right direction! What with it being Memorial Day weekend I didn't expect anyone to even notice this thread.
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Glad to help and I do check in here as often as I can so no post goes unread for the most part. Sounds like you have the wiring covered so you may find that the pump is just dead/shorted. It's pretty common knowledge that the GM trucks have had problems with fuel pumps for many years, so it definitely would'nt be unheared of if thats whats going on here.
  8. northernnewbie

    northernnewbie Member
    Messages: 31


    Drove it home fine from the repair shop, no work was done. She drives fine at highway speeds but at idle she lopes too slow (400-500 rpm) and drops dangerously close to stalling when changing between p-r-n-d-3-2-1. The headlights dim when this happens too....alternator perhaps...?

    I isolated a short down to the wiring in the plow headlights but there is still some current being drawn elsewhere. Battery is having a hard time holding a charge but is doing better with the plow stuff totally disconnected.

    Can anyone tell me how to full field the internal voltage regulator for this type of alternator?

    Still trying to find a fuel pressure gauge, neither VIP or Autozone have one and my repair shop practically laughed at me for asking about it.

    I replaced the fuel filter which felt satisfying to do though it had no apparent effect. I'm charging the battery right now, which is B.S. because its a 9 month old Duralast. Wish me luck.

    Tomorrow To Do List:
    1. Change Oil
    2. Flush Brake Fluid
    3. Inspect Spark Plugs
    4. Bench Test Alternator
    Last edited: Jun 3, 2007
  9. dodgeguy99

    dodgeguy99 Senior Member
    from mn
    Messages: 272

    i got a fuel pressure gauge at o reily i believe it was around $40
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Its sounds like your on the right track as far as something drawing too much current. I'd still suspect the fuel pump as a possible culprit. Also, a poor ground connection between the battery/frame/engine so be sure to check ALL ground connections (these trucks have many). I'd also test the charging system like you mentioned in order to check the health of the battery and especially the alternator, as a large current draw (such as a short) can really tax the alternator and shorten it's life. Theirs really no way to command the alternator to full output through the field circuit as it's controlled by the PCM but you can still check it either by bench testing it or connecting a charging system analyzer to the truck.