when i turn the key im getting 61 pounds of pressure, my question is how long should it hold?? also if someone could tell me what the ground wires on the back of the head are for?

 

The Pressure should hold for a long time......you shouldnt loose more than 5 psi in an hour. IF you do...you got problems. The ground wires on the back of the head are for a number of things....They all go somewhere and are all nesseciary.

 

ok cool, im dropping like 5 psi every minute or so, i pulled the upper intake and hooked fuel lines back up. i didnt see any leaks from the FPR but it was a little wet in there.
the reason i asked about the grounds was beacause i just put new heads on it and had to splice two together, would that cause any issues?

 

it shouldnt if you spliced the wires together good (solder), if the upper intake is wet then you have a leak rather it be a O-ring, FPR, line or injector.

 

ok thanks for the help, guess ill be doing the spider assy.

 

are you getting a random misfire code(P0300) or engine surging/bucking?

 

yes its missing very bad, i havent had it running long enough to throw a code yet. thats kinda what is making it so hard to diagnose. just put new heads on and didnt take the upper off then. i took the upper off last night and hooked the gas lines back up. then i turned the ignition switch on and looked for leaks, i didnt notice any but the dropping fuel pressure means its going somewhere. i really dont wanna turn this into a parts changing job. im probally gonna change the regulator tommorow unless you have other ideas.

 

well their are only two spots where fuel pressure drops without an actual break in the line. the intake (spider assembly/FPR) and the gas tank (Fuel Pump). if its running bad then i would say its an injector assembly... gust wondering waht year your truck is....becasue if its 96 or newer then their is a fuel injector upgrade kit from SCPI to MFI which eliminates the poppet nozzels and gives a more reliable injector assembly...

http://www.gmpartsdirect.com/results...ber=pk19210688

 

I take it the engine is NOT running when you are watching the fuel pressure drop. If that's the case, then the fuel pump brings pressure UP when you first turn the switch on, but without the oil pressure switch function and the motor NOT running, the fuel pump will not run again.

There is a check valve in the fuel pump which keeps fuel from leaking backward when the pump is off. Also, the pressure regulator can bleed pressure off if the seat is not perfect. Thirdly, as already mentioned, one of the injectors may bleed pressure by leaking fuel into the intake.

You mention 5 psi per hour drop. Because of the small volume of the fuel lines, this might be less than a tea-spoon of fuel getting past a valve seat in one hour. Do you consider that a problem?

Just asking.

 

its an 02 model, thats what i was planning on doing, upgrading the assembly. i found it at orielly's for 299, didnt seem bad to me. anyone recomend that one,lol. i do body and paint for a living so i know about cheap aftermarket parts! just curious?
oh and to billbo, its 5 psi every 5 min. if it was 5 every hour do you think i would be up here asking why its missing so bad?