Runs fine for 15 seconds then dies and won’t start
 

97 Chevy with the vortec V6. Truck sat for few years and then got running again. Due to sitting for so long etc went ahead and put the MPI system on to replace the spider. Cleaned out old gas and everything. Now when it starts up it will run perfectly fine to 3000 rpms for about 15-30 seconds and then it dies. If u try to restart it immediately it will backfire and cough but will not start. Come back 15 minutes later and fires right up and runs good for another 15 seconds and then dies. Any ideas???
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Re: Runs fine for 15 seconds then dies and won’t start
 

Find out what the fuel pressure is doing. Sounds to me like your fuel sock could be partially or mostly blocked so the pump starves for fuel in a short period of time. After it sits for while under vacuum it eventually fills the fuel line up again.

If you don't have a fuel pressure gauge and don't want to buy one, see if you can borrow one from the tool loaner section of the local auto parts store.

Re: Runs fine for 15 seconds then dies and won’t start
 

Possible ignition module failure.

Re: Runs fine for 15 seconds then dies and won’t start
 

im betting its fuel related id check the pressure like the other guy said

Re: Runs fine for 15 seconds then dies and won’t start
 

Checked fuel pressure and as soon as truck is cranked it jumps up to right around 55 and hold solid even as truck dies. Then continues holding for minutes after dead. Thinking it probably is the ignition module, havent had a chance to test it yet but that is my next step.

Re: Runs fine for 15 seconds then dies and won’t start
 

some years ago I had a similar symptom. Not only was my ICM bad, but along with it was a bad coil. ...and both were not that old!!

Re: Runs fine for 15 seconds then dies and won’t start
 

When you start the truck does it not turn the fuel pump on with
a cranking relay then switch to a oil pressure switch to run the pump?
Or is that tbi only?

Re: Runs fine for 15 seconds then dies and won’t start
 

So I didn’t actually do the work on this truck but when I laid eyes on it within 3 minutes had problem fixed. The mechanic that redid spider neglected to put air intake tube back on and of course the mass airflow sensor was killing it. Put it back on and runs perfectly! Now my problems is with the brakes not wanting to be bled but that’s another thread
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