1997 GMC Sierra Repair Question
Intermittent failure to start
Randomly, the truck will fail to start. When it does start, it runs a little rough, but it accelerates and idles without significant issue. There doesn't seem to be any consistent set of conditions when it fails to start - it could be morning, noon, night, wet, dry, hot or cold (weather) or hot or cold (engine).
When this occurs, I do notice that I can't hear the fuel pump "priming" when the key is turned to the start position, but before attempting to crank the engine. I thought it might be a short or bad connection to the fuel pump, but haven't been able to trace it down.
Also, without any understanding of why, the truck will frequently start and run OK again for awhile after it sits for a few hours after trying to start it. To reiterate again though, it doesn't seem to be tied to the engine temperature.
Any thoughts/troubleshooting tips?
Get a spark tester ST-125 and a fuel pressure gauge-hook it-don't wait for nothing-attempt to start -this will tell you something what's missing make sure you have a helper to observe
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I think I discovered the issue (and a new problem?). Before I dropped the tank to replace the fuel pump last year, I replaced the fuel relay (in the fuse box under the hood). On a hunch, I pulled it out to reseat it and noticed some "scorching" on one of the terminals (#30 pin). One I cleaned it off, the fuel pump kicked in on the first try and the engine fired up.
When I got the truck home, I pulled the relay again to clean it up better and noticed that it was very warm and smelled of ozone. I plan to get another replacement, but am now concerned that something else may be going on to cause this relay to fail so quickly (probably ran less than 20-40 hours with this relay).
1 question asked
Relay getting hot to the touch-could be short circuit somewhere
68 questions asked