89 GMC 3500 TBI flooding

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Sep 8, 2019
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#1
Make
GMC
Model
3500
Year
1989
Miles
?
Engine
454
I have a 89 GMC 3500 with a 454 TBI. Runs ok when cold and as soon as it warms up or running in warm weather floods out. You can smell the fuel. Any ideas what could be causing it?
 

billr

wrench
Staff member
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#3
Live-data may be tough to get on this old beast, but that ECT sensor can be checked with a voltmeter. Let us know if you need instructions on testing.
 

grcauto

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#4
GM should have live data. If that old girl uses the EFE system make sure the valves are opening correctly when they warm.
 
Joined
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#5
remove the air cleaner - inspect the injector harness as it passes under the airfilter-prone to wires grounding out.

Next with filter assembly removed - turn key to RUN engine off - are the injectors spraying?