Hello all, my 98 1500 stock 5.7L vortec (185k miles) started having long crank issues. Put a fuel pressure gage on it and when the key is turned on, the pressure jumps to 62-64. But as soon as the relay clicks the pressure drops to 0 within 15 seconds. Pulled the plenum top expecting to see the regulator leaking but see nothing coming from the vacuum port. Pulled each injector, pressurized the system and no leaks noted.
Can the regulator leak internally? Can it Bypass to the return without a visible leak? Im pretty sure the pump doesnt have a one-way for the return, or am i wrong? I just dont know where that 62 psi is going so quick.
thanks in advance!
Dave
You can have long crank issues for several reasons besides fuel pump issues. While I have heard people lament that fuel pressure should hold for some period of time when the pump stops running, as a 40+ year ASE Master L1 tech specializing in Domestic vehicles I have NEVER found pressure fall off to be any sort of reliable indicator of fuel supply system function. How LONG is it cranking? Do you have the equipment to read sensor data?
Rush to judgements are RARELY = succesful repairs. YESTERDAY, my brother called me about the '99 K2500 he is fixing up to sell. Out of the blue it wouldn't start after just driving it. Just cranked over. Everyone around him assumed it wasn't getting fuel. I got on the phone and after a few questions told him to hold the pedal to the floor, and it started. It was flooded. Then everyone around him told him his pressure regulator or spider assembly was leaking.
He brought it to me, and the coolant sensor was reading 5* on a warm engine because the sensor terminals and those in the pigtail were corroded. The incorrect temp reading caused the flooding and long cranking. There was NO coolant sensor code and no check engine light, because 5* is a plausible reading. A new sensor and pigtail fixed his flooding/fuel supply issues.
So bottom line, don't jump to conclusions, or follow other people's jump to conclusions.
If the engine is being over fueled for any reason, it should start quicker with a fullly depressed throttle. With the repeat of this simple test you should be able to conclude whether the motor is flooding from a leak or not without taking anything apart.
Is it always slow to crank, or just sometimes? And under what conditions?
Tom