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2001 GMC Sonoma 4.3 starting problem


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ealexander
New User

Nov 16, 2014, 6:23 PM

Post #1 of 2 (1153 views)
2001 GMC Sonoma 4.3 starting problem Sign In

For the past year my truck has had a starting problem. First thing in the morning it will start right up but after driving somewhere and sitting any amount of time it takes up to 20+ times to start. First I thought it was a fuel problem. Replaced fuel pump twice also had several fuel filters since. Fuel pressure is fine. Started thinking it might be electrical. Replaced plugs, wires, rotor button, cap and module. While doing so notice what ever round thing under button is called was wobbly in distributor shaft so replaced distributor too. Still same problem. Noticed few days later that pig tail on crank shaft position sensor had exposed wires but didn't seem to be touching. Went ahead and got new pig tail from parts store and will be wiring it in when I get a chance. Don't really think it will be my problem. Truck runs great once it starts. Just takes time to start it. Apreciate any help given.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 16, 2014, 7:02 PM

Post #2 of 2 (1142 views)
Re: 2001 GMC Sonoma 4.3 starting problem Sign In

 
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 tested 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 injector 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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