98 Chev won't start

I have pretty well the same situationa as described below. 98 Chev

1500 5.0L. The fuel pump was replaced in Aug., I replaced the Fuel Relay this past weekend. It has died twice now in the past week, in that it will not start for a day or two, then the next day it starts! When it will not start you do NOT hear the fuel pump run for 2 seconds as it should, so something is stopping the fuel pump from getting power.

Is any magic spot the wires usually short on the way to the fuel?

How about testing the oil pressure switch? Is this possible without specialty tools?

Just one more reason why I will never buy a Chev again!

- Large

I'm trying to help out a friend that is having some problems with his > truck - it won't start - it seems like the fuel pump. It's done this a few > times, where it will crank over but won't start. Weird thing is that later > on, or maybe the next day, it decides to start. Whenever it does not start, > he doesn't hear the fuel pump going when he turns the key on. SO, I'm > thinking it's either the relay or the pump, no? Since the pump is pretty > expensive, I was wondering about the best way to test it....I'm thinking > that if we are getting 12 volts to it and it's not on, it's toast. Also, > if we need to replace the pump, the easiest way is to drop the tank, right? > Another buddy of his is suggesting pulling the bed off....sounds kind of > extreme to me. > > Any thoughts or comments would be greatly appreciated. > thanks, > Greg

Greg,

1) Fuel Pump Relay

2) Fuel Pump

3) Oil Pressure Switch (used to kill fuel pump in lieu of oil pressure)

4) Shorted wiring somewhere in the fuel delivery circuit

It could be any of the above 4. Check out all the wiring FIRST. If all checks out replace the relay before the pump. The relay has a failure rate greater than that of the fuel pump itself and is much cheaper and less work to R&R. And yes, if the pump needs replacing you need to drop the tank. Pulling the bed off is just a ludicrous suggestion!

You have checked for spark and fuel delivery duroing the no-start circumstances right? Don't assume it's fuel because it won't start until you've verfied spark.

Doc

Reply to
Large
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Has anyone looked for a passlock code in the BCM....You have a sensor in the key cylinder...Which if it dont get the code it wants wount let your truck start....Sometimes it will grab the right code and start ...Had one with the same symtoms took forever to diagnose....Ended up replaceing the key cylibnder ignition switch and cleared he codes reprogrammed the bcm and it started right up.....May be you should try that ...to find out all you need to do is pull the code from the BCM not the PCM but the BCM if you get a passlock anti thieft code or you have one in your history the Body control module will not alow the truck t start... Steve C

Reply to
Steve Cook

"Large" wrote

Usually, wiring problems occur inside the tank, or where the wiring harness connects to the fuel tank module. Often, you can have a fuel pump replaced, and if the wiring is not inspected properly, there can be bad wiring connections that work for a while after having been unplugged and plugged back in again.

Why would you check the oil pressure switch? Lack of oil pressure has no effect on the fuel pump. Contrary to popular belief.....the oil pressure switch is designed to provide "another" route for power to the fuel pump if the fuel pump relay goes belly up. It wasn't designed to shut off the fuel pump if oil pressure is lost.

Ian

Reply to
shiden_kai

Thanks for the tips. The oil switch idea came from the web site All Data, but yes, the web site also stated that the oil switch is an alternative power path, not a cuttoff.

It would not start again yesterday... have not tried yet today.

- L

Reply to
Large

I had the truck to an autoshop two Mondays ago but they claimed they found no error codes, but as you state maybe they looked at the PCM only.

I also had passlock error a year back as my remote starter bypass of the passlock system failed twice when I used the remote starter, but I have not used the remote starter during this problem phase. When the remote started failed in the past it would reset and clear in 10 minutes, and then start via the key.

Oh, the fun continues...

- Large

Reply to
Large

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