Quote:
Originally Posted by jthomp23777
2001 Tahoe,130,000. Having starting hesitation problem on start up. Does not fire as quickly as used to.Fuel pump is original. I did a fuel pressure test. I get 58 psi on ignition turn on,55 psi when running.The pressure test gauge will not maintain pressure on just turning the key in the on position, it leaks down quite quickly.Should'nt the fuel pump maintain pressure on the fuel system with the key just in the ON position?The gauge maintains pressure hovering at 55 when the engine is running.All other coponents are well maintain,plugs at 88,000,fuel filter every 10,000,throttle body cleaned regularly,battery holding load and at 14 volt,starter appears to be turning engine over other than it engages longer due to this start up problem. I guess my question is with the pressure test gauge leaking down quickly is this normal or not?? Thanks
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the fuel pressure must hold for 15 min at the pressure when the engine is running within a few psi...if it rapidly drops this is usually a bad fuel pump....
check the fuel regulator for fuel in the vac line going to it...the injectors ,,,may be leaking down but if that where the case with the drop off very rapid I would think this would cause engine issues/dtc..
when you start,, turn key to ignition ,,,wait two seconds engage starter..
the 55psi is on the low side,,,but your gauge may be off a little..
when you install a new pump only use the DELPHI PUMP...THEN measure the fuel pressure and test for holding of pressure....you may also for insurance replace the fuel pump relay as well...