Skip the auto shop - Our mechanics make house calls

Q: Fuel pressure test leaks

asked by on

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.

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Damage to rear Differential? 1994 Chevrolet K2500

Hello - while you are correct that this is not an ideal scenario, I doubt that packing the bearings with a lithium grease like "Red & Tacky" is a long-term issue. Not sure where R&T gets a bad rap as...

Q: Where is the fuel pump shut-off switch located?

Your car may have a fuel pump shut-off switch. This switch turns off the pump that sends gasoline from the fuel tank to the engine. It’s designed to activate during certain situations, such as during an accident. If you’ve been...

Q: Around 2000 rpm, car shifts erratically from 4 to 3 gear, code comes up as Bad Shift Solenoid C

Hi there, thanks for writing in. Based off your details, you could possibly have a problem with the transmission front pump seal that will not let the lock up torque converter go into overdrive, and may set codes for overdrive....

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...