The tester connects to the service port located at the rear of the engine toward the driver side of the distributor. It looks similar to a valve stem on a tire with a valve inside of it, may have a black plastic cap on it. On 1998 and newer, in the underhood fuse panel there is a vacant terminal next to the fuel pump relay. This is the "fuel pump prime terminal" and it goes directly to the fuel pump. Connect a jumper wire from battery positive to the terminal. After the fuel pressure stabilizes, it must be 60psi to 66psi. Then remove the jumper wire and the fuel pressure must remain above 55psi for at least 10 minutes. If it fails either or both parts of the test, there is a problem with fuel delivery and further testing is required to pinpoint the problem. Post your results.

 

The fuel pump is good im thinking its the injectors my mechanic says its probably the injectors to. is there any way i can clean them to see if it helps ?

 

By "the fuel pump is good" do you mean that you ran the pressure test and got results within the specification or did you just hear the fuel pump come on and assume it was producing proper pressure and holding it? A lot of people make the mistake to assume the pump is fine just because it turns on and makes some noise.

Before you can determine the problem is definitely the injectors you have to do some more testing. If the fuel pressure is low or drops off right away then you could have a problem with the injectors, the lines, the regulator, the pump, or some combination thereof. Make sure you've got actual hard numbers. That will help in finding exactly where the problem is and save you a lot of money in the process.

 

If you want to keep guessing at what's causing the problem, that's fine. If you want to know what the problem is, I agree with Toby, you need to post the fuel pressure while the pump is running, (engine off) and the pressure 10 minutes after the pump shuts off. The results will tell us what the next diagnostic step is.

 

my Mechanic did the pressure test its the injectors that are going in it the pump is fine he said it looked new i guess the previous owner did it. hes had blazers before he was telling me to not get one but i needed a vehicle quick Thanks for your guys help.

 

Pump looked new...huh.

 

I have a couple of fuel pumps in my garage that "look" new. One develops a whopping 3 PSI and holds it for almost 10 seconds. The other does nothing at all...But they both "look" good.

 

he did the test for the pump and the injector spider. The pump is a delpi pump so it has obviously been replaced. Its a clogged cat that's causing it the hesitation. Out of the driveway she goes nothing but problems.