Skip the auto shop - Our mechanics make house calls

Q: No fuel pressure at the rail. Changed the pump, filter and pressure regulator. Could this be electronic or the cpi unit?

asked by on

Drove to the store, no issues. In and out in less than 5 min, it would not start. Had it towed home. Tried there and it fired up. Drove it to work and back, no issues. Following day, no start. Changed the fuel pump, filter and regulator, still will not start. Checked pressure at the rail, only getting 20 lbs then dropping to 18 and holding. Could this be electrical or the cpi unit?

My car has 278 miles.
My car has an automatic transmission.

A: Hi! I’d suggest performing a voltage drop t...

Hi! I’d suggest performing a voltage drop test at the fuel pump connector. That will verify that you have good power and ground at the pump. You could also put a new fuel pump relay in it, or swap it out with one of the others to see if it makes a difference. You should have at least 60 psi while cranking. If you block the return while cranking and pressure goes up, it’s a bad regulator. If not, and power and ground to the pump are good, its a bad pump. If you need assistance in this process, a certified mobile mechanic from YourMechanic can come to your home or office to inspect the issue and provide any necessary repairs.

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

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: car won't start and no fuel pressure at rail but great at the filter

If the pressure drop exists "through" the fuel filter, then the fuel filter should be replaced. If the pressure at the exit side of the fuel filter is normal and yet the pressure on the fuel rail is essentially zero,...

Q: Welding the harmonic balancer to crank shaft? 1991 Chevrolet S10

Hello - No, welding the harmonic balancer to the crankshaft is not a good idea for at least 2 reasons. Welding the balancer hub to the crankshaft will damage or reverse the benefits of heat-treatment to the crankshaft itself -...

Q: I wanted to know how much it would cost for the entire exhaust system to be fixed

Hey there. For an entire exhaust system replacement, I would suggest getting in touch with a local exhaust shop to quote you for the repairs since your exhaust system is no longer sold by the dealers due to its age....

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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...