ok the first thing is when its hot out and ive been driving around the city if i shut it off and go to start it, it takes a few cranks to start and then it wants to die if i dont press the gas a bit , it has a new fuel pump and new filter.

second, i bought a a/c/ recharge kit because my a/c blows slightly cool air , i hooked up the hose to the low side and the guage goes from 120 with the a/c clutch off to 25 when the clutch is engaged, should the add the recharge can or what should i do i want my a/c to work??


thanks

 

Check fuel pressure and leakdown. Key ON, engine OFF, fuel pump running: pressure must be 60psi to 66psi. It must remain above 55psi for at least 10 minutes after the pump shuts off. Post your results.

A/C: With the engine running at ~1500 RPM, A/C set to MAX, windows and doors closed, ambient temperature ~70F, low side pressure should cycle. The clutch should turn on at 42psi and shut off at 22psi. If ambient temp is above ~80F, the clutch may remain on constantly. Checking pressures alone will not determine the amount of charge. The only way to know how much refrigerant is in the system, is to drain, evacuate to 29.4"Hg for at least one hour and recharge with the proper amount of refrigerant.

 

ok thanks, i think i got the a/c working , ill have to buy or borrow a fuel pressure gauage.

 

ok i finally got a fuel pressure guage and when its running its at 50 psi and when i turn it off it goes down to 0 . it has a new fuel pump and filter

 

On 1998 and newer, you can activate the fuel pump continuously to test fuel pressure. Apply battery voltage to the pump prime terminal in the underhood fuse panel. After you obtain a steady pressure reading, remove voltage from the terminal. Fuel pressure must remain above 55psi for at least 10 minutes after you remove the voltage. These two tests check the overall condition of the entire fuel delivery system, (fuel pump, pressure lines, injectors for leakage, and both functions of the fuel pressure regulator). If it fails one or both tests, it does not tell what the problem is, it only tells that a problem exists. Further testing is necessary to pinpoint the problem. GM does not publish any "engine running" fuel pressure specs for this engine, there are far too many variables involved.


We need to know what fuel pressure is with the pump activated and the engine OFF. From the results that you posted, there is a problem with excessive leakdown. To determine where the leak is, you'll need to do some "creative plumbing" with the pressure tester. It needs to connect to the outlet of the fuel filter so all fuel pressure and flow ends at the tester. While the pump is activated, pressure must be 73psi to 108psi and it must remain above 55psi for at least 10 minutes after the pump is deactivated. Post the results and we'll continue with diagnosis.

 

ok thanks ill try what you have suggested

 

ok so i finally got around to hooking it up to the fuel filter, with the jumper wire i got the pressure up to 100 psi and as soon as turn it off the pressure drops to 0 , it is a new pump, could it be faulty??

 

Maximum output is good, but leakdown fails miserably. Must remain above 55psi for at least 10 minutes. The pump is bad.

 

ok great , its only a few months old , so the pump should be holding the pressure but it isnt , it must be leaking it back thurough the pump in to the tank.

 

That sounds right to me. Is the pump an AC Delco or a Delphi? If not, then be sure and replace it with one of those. They are the factory pumps and hold up best to the long-term needs of the high-pressure fuel systems in our trucks.