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wjackson95
New User
Jun 30, 2009, 5:52 AM
Post #1 of 2
(2773 views)
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1999 GMC Sierra 1500 - 5.3
Truck suddenly stopped while going down the road. Waited a few minutes and it started back up. It will start right up at times and not at other times. Problem started last summer, 2008. Put in new fuel filter and plugs and wires; truck ran fine until this summer, 2009, changed fuel filter again. Runs good for a while, but turn it off and it might start and it might not. Put fuel pump in in 2007. Sometimes pops when trying to start and fuel smells.
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Hammer Time
Ultimate Carjunky
/ Moderator
Jun 30, 2009, 9:38 AM
Post #2 of 2
(2767 views)
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Re: 1999 GMC Sierra
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All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be test during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.
Every engine requires spark, fuel and compression to run. That's what we have to look for.
These are the basics that need to be tested and will give us the info required to isolate a cause.
1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.
2) Test for injecter pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.
3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.
Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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