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Q: Fuel pressure test leaks

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My GMC had leaking gaskets, so I replaced them by removing the upper and lower intake manifolds. I had some fuel pressure bleed down, so I replaced the injectors, fuel pressure regulator and fuel rail. Now I have the lower intake manifold bolted in and the new pressure regulator rail and injectors installed. I attached the connectors to the injectors, but I didn't connect the droves of other connectors, because I'm only half done with this job. Before I do any more assembly and fixing, I want to do a fuel pressure test to check for leaks. I will have to do this test without the fuel pump as the manual directs. My fuel pump isn't working right now because so many things are disassembled. Do you know which connectors need to be attached to make this build pressure? I need to check for leaks first.

A: Hello there. It sounds like you have a few ...

Hello there. It sounds like you have a few things going on with your 1996 GMC C2500. While I commend you on wanting to check for leaks in the fuel system, this is a little tougher than you would think. With the vehicle in its half-put-together state, you cannot start the vehicle. The fuel pump is powered when the key is cycled from off to run. The intake manifold contains sensors such as the knock sensors, a MAP sensor, a coolant temperature sensor, and various others. Without the readings from those sensors the car will not activate the fuel pump and allow you to test fuel pressure. If you need help pinpointing the leaks, an expert from YourMechanic can come to your car’s location to have this addressed accordingly.

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