Hard to start when warm 2001 4.3l 4wd

[boborc]

Hello, i have a 2001 sonoma v6 4wd. It is hard to start only when warm takes about 5 to 10 seconds of cranking before it starts. On a chilly morning starts right up. If you stop at D&D for coffee and come out within 5 minutes starts right up. if you let it sit 10 to 60 minutes where the engine is warm or now even if the temp is above 60 degrees its hard to start.Replaced the IAC already and cleaned the intake. Also ran 2 cans fuel injector cleaner thru it.25k on full tune-up and just replaced the cap and rotor again.Runs great when its running.No engine light. any idea's???

[MT-2500]

Originally Posted by boborc

Hello, i have a 2001 sonoma v6 4wd. It is hard to start only when warm takes about 5 to 10 seconds of cranking before it starts. On a chilly morning starts right up. If you stop at D&D for coffee and come out within 5 minutes starts right up. if you let it sit 10 to 60 minutes where the engine is warm or now even if the temp is above 60 degrees its hard to start.Replaced the IAC already and cleaned the intake. Also ran 2 cans fuel injector cleaner thru it.25k on full tune-up and just replaced the cap and rotor again.Runs great when its running.No engine light. any idea's???

Any codes?

I would run a full fuel pressure test and watch the fuel pressure when hard to start.
And watch for fast leak down.
Get it on a good engine capable scanner and check fuel trims and engine tempt and air tempt readings in scanner.
Make sure they match engine tempt.

[boborc]

No Codes I think,If there is one won't the service light come -on or do I have to hook it up to the scanner anyway?I was thinking of the relief valve in the gas tank but why does it only happen when the engine is warm? and works fine after sitting for a long period of time.I'am going to check pressure I quess I'am feeling maybe an injector or something is hanging up and actually flooding it out in that time and if it sits long enough it evaporates or a temp sensor on the fritz???

[djd99]

Originally Posted by boborc

No Codes I think,If there is one won't the service light come -on or do I have to hook it up to the scanner anyway?I was thinking of the relief valve in the gas tank but why does it only happen when the engine is warm? and works fine after sitting for a long period of time.I'am going to check pressure I quess I'am feeling maybe an injector or something is hanging up and actually flooding it out in that time and if it sits long enough it evaporates or a temp sensor on the fritz???

Listen to mt and check your fuel pressure, it sounds like you could be experiencing a fuel pump going bad. What I would do is hook up your fuel pressure gauge and tape it to your windshield for a week or so and see what your pump is doing. That's how I found out mine was bad. You should have 60 plus at prime. Mine needed 62 for a cold start.

[duke350]

A halfway decent scantool or codereader will tell you of any active or pending codes. If a code is pending, or not currently active the light will not come on.

[bowtiekidd]

Did you figure out what the problem was because I have a 01 that is doing the exact sameting