1991 r3500n 454 cfi, cold start issues.... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cag · Today, 06:35 PM

this cfi 454 on start up runs really rough and backfires sometimes, any idea what is going on???

**Bob B.** · Today, 11:06 PM

When you shut the engine off, is there fuel leaking from the injectors flooding the intake manifold? Also check to make sure the engine coolant temp. sensor (the one for the computer, not the gauge) is reading properly. You can check it with a scan tool. Sometimes they can be way off and cause hard start problems. Does in run O.K. once it warms up?

Today, 06:35 PM	#1
cag Registered User Join Date: Aug 2022 Location: winneconne, wisco Posts: 42	1991 r3500n 454 cfi, cold start issues.... this cfi 454 on start up runs really rough and backfires sometimes, any idea what is going on???

Today, 11:06 PM	#2
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,351	Re: 1991 r3500n 454 cfi, cold start issues.... When you shut the engine off, is there fuel leaking from the injectors flooding the intake manifold? Also check to make sure the engine coolant temp. sensor (the one for the computer, not the gauge) is reading properly. You can check it with a scan tool. Sometimes they can be way off and cause hard start problems. Does in run O.K. once it warms up? __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.



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