fuel pressure
jmarling
07-15-2007, 07:24 PM
whenever i let my 91 sonoma set for a half hour or longer it loses its fuel pressure and it takes forever to get it to run,but if i dump a little gas in throttle body it fires right up. any idea why it wont hold pressure in the line?
MT-2500
07-16-2007, 09:57 AM
Weak fuel pump or fuel filter stopped up.
Run a fuel pressure test on fuel pump.
Make sure it is up to specs and putting out full pressure.
MT
Run a fuel pressure test on fuel pump.
Make sure it is up to specs and putting out full pressure.
MT
jmarling
07-16-2007, 11:45 AM
it runs fine once i have it started,and i just put a new filter on it,i thought fuel stayed in the line for the next start up,and its bleeding out somehow. will a weak pump let it bleed back to tank?
MT-2500
07-16-2007, 01:16 PM
No on weak fuel pump bleeding back.
But You have to have pressure before it can bleed off.
Check you fuel pressure and watch for a fast leak down after shut off.
A fuel pressure regulator or leaking injector or a fuel line leaking can leak off pressure.
The fuel pump check can leak off pressure after pump is off but not when running.
Check direct fuel pump pressure.
You fuel pummp should put out 16-20 lbs direct pressure and should hold 9-13 lbs running pressure.
MT
But You have to have pressure before it can bleed off.
Check you fuel pressure and watch for a fast leak down after shut off.
A fuel pressure regulator or leaking injector or a fuel line leaking can leak off pressure.
The fuel pump check can leak off pressure after pump is off but not when running.
Check direct fuel pump pressure.
You fuel pummp should put out 16-20 lbs direct pressure and should hold 9-13 lbs running pressure.
MT
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