Skip the auto shop - Our mechanics make house calls

Q: Truck won't start unless I remove the fuel pump relay

asked by on

I just did a head job on my 90 nissan d21 with a 2.4 now the truck won't start unless you unhook the fuel pump relay then as soon as it cranks hurry and hook it back up. When it does crank it runs really rough and idle up and down. Once you shut it off you have to go through the whole process over again. I've changed the fuel pressure regulator and still no change.

My car has 165000 miles.
My car has a manual transmission.

A: Hey there. This is a sign of a failing fuel...

Hey there. This is a sign of a failing fuel pump or potentially a faulty power connection to the fuel pump. As you know, if the fuel pump fails to supply adequate fuel pressure to the motor, this will cause an imbalanced fuel load to be supplied to the motor resulting in the erratic idle you have experienced. I would recommend replacing the fuel pump.

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・Save up to 30%

Get a quote

What others are asking

Q: Car is overheating quick

Hello. If the gauge goes hot instantly when first started in the morning, then you may have a faulty gauge or coolant temperature sensor. For this car in particular the sensor is usually problem. If the temperature shows cold at...

Q: Driver's side door won't open

If the driver side door will not open then most of the time this is caused by a broken door latch that should be repalaced. If neither handle works then the latch is broken inside of the door or the...

Q: Inertia switch/Fuel pump

The inertia switch is supposed to totally disable the fuel pump power supply when the vehicle is in an accident or rolls over. You will need to check the power connector into and out of the inertia switch to make...

Related articles

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.