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Dave Nova
Dave Nova, GMC Technician
Category: GM
Satisfied Customers: 19451
Experience:  ASE Master Certification. GM World Class Certification
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2001 GMC: 4X4..It cranks over but wont start...getting fuel

Customer Question

I have a 2001 GMC Jimmy 4.3L 4X4. It cranks over but won't start. It is getting fuel and is getting spark but behaves like its badly out of time. I have changed the ignition module and checked position sensor (compared resistance readings to a new one and everything was identical). Could you tell me if anything else affects timing or could cause this condition?
I tried spraying fuel in the intake while it was cranking and it made no difference.
The truck ran perfect the last time we used it, then a day later won't start.
Submitted: 6 years ago.
Category: GM
Expert:  Dave Nova replied 6 years ago.
The timing is set by the crank position sensor, cam position sensor (in distributor), and the computer. Have you taken a fuel pressure reading?
Customer: replied 6 years ago.
yes, guage showed 55 psi
Expert:  Dave Nova replied 6 years ago.
Does fuel pressure hold, or drop off right away?
Customer: replied 6 years ago.
It holds
Expert:  Dave Nova replied 6 years ago.
Remove the air intake tube from the engine and spray starting fluid into the intake while cranking the engine. Does the engine start?
Customer: replied 6 years ago.
I tried spraying fuel in the intake while it was cranking and it made no difference, plugs had fuel on them before I tried that, but I tried it anyway.
Expert:  Dave Nova replied 6 years ago.
If the plugs are fuel soaked, the problem is most likely a leaking fuel pressure regulator or cracked feed line inside the intake manifold. This is flooding the engine and not allowing it to start. Remove the upper intake plenum and inspect the internal fuel lines and the fuel pressure regulator for fuel leaks.
Customer: replied 6 years ago.
What you are talking about could this cause it to occasionally back fire through the intake
or fire out of time to stop the starter from turning?
Expert:  Dave Nova replied 6 years ago.
Yes, the overabundance of fuel present can cause a backfire, which would come through the intake manifold or abruptly stop the engine from turning over.
Customer: replied 6 years ago.
Is there a way of letting you know if thats what the problem is and being able to say Thank-you or do I just click on the accept button, my husband is just checking.
Expert:  Dave Nova replied 6 years ago.
You can still reply to me after accepting the answer. I will continue to follow up with you as needed.
Dave Nova and other GM Specialists are ready to help you
Customer: replied 6 years ago.
Hello Dave,
I removed the fuel meter body it does not seem to have any cracks and the lines look ok internally but there is fuel in the plenum, should the bracket that holds the metering body be loose even though bolt is tight?
Expert:  Dave Nova replied 6 years ago.
Yes, this is normal, it allows the metering body to align with the upper plenum. Try connecting the fuel lines without the upper plenum in place. Then cycle the key afew times to build fuel pressure. This will help to determine where the fuel is coming from. It will most likely be coming from the port on the fuel pressure regulator.
Customer: replied 6 years ago.
I hooked up fuel metering body as you suggested cycled key several times and no leaks anywhere and injectors appeared to squirt normally. Maybe fuel that was in intake came from disasembling.
From the beginning codes read p0155, p0442 and p0446.
Expert:  Dave Nova replied 6 years ago.

The P0155 code is for an O2 sensor that is unresponsive. This code will not set until the engine is running, so it is not the cause of the no start condition. P0442 and P0446 codes are for leaks in the evaporative emisssion system, possibly a loose gas cap, again not the cause of the no start. I would suggest clearing these codes and see if they reappear after the engine has been run.

 

I know you said you have good spark, try removing the distributor cap and inspect the inside of the cap for moisture and corrosion buildup. This is somewhat common on these engines. Let me know what you find.

Customer: replied 6 years ago.
There is some corrosion in there but no moisture, corrosion is no worse than in any running engine that I have seen. This is stumping me.
Expert:  Dave Nova replied 6 years ago.
Since plugs were wet with fuel, you may wnat to remove all the plugs and dry them. Crank the engine over with the plugs out to clear the cylinders. Put everything back together and try starting the engine again to see what happens.
Customer: replied 6 years ago.
Well I got it running although I checked the rotor and cap, I decided to give it closer inspection and found it needed changing now it runs.
Thank-you so much for the help, I really learned alot from all of this, it was'nt the greatest week-end especially when it was such a simple problem.
Thank-you
Expert:  Dave Nova replied 6 years ago.
You are welcome. Thanks for using Just answer. I am sorry I didn't suggest it sooner, but assumed since you had been into the distributor that this was something you had checked out.
Customer: replied 6 years ago.
I did check it out but apparently I did not inspect it close enough.
Thank-you
Expert:  Dave Nova replied 6 years ago.
You are welcome.