Skip the auto shop - Our mechanics make house calls

Q: Fuel pump will not kick on.

asked by on

OK So I have replaced the fuel pump, fuel pump relay, and the fuel pump fuse. Installed everything and the fuel pump will not kick on. So I dropped the tank again. First through the pump wiring harness, I check the voltage. At the Purple wire and the black/white wire I got 10v (level gauge). Then I checked the gray wire and black wire while someone turned the key to run, I got 12.98v for about 5 seconds and then had them crank the engine and got anywhere from 10-12.5v while cranking. So I then thought it might be a faulty pump, Autozone gave me a new pump to try and still same issue. So i then thought it could be a ground. I checked the ground and it came out to be .3 ohms, which i believe is ok. Then i check the continuity of all the wires on the pump harness and they were fine. I read something online about the passlock system, although the security litght was not flashing i tried the 10 and 30 min relearn still nothing. BTW checked every fuse and relay. No engine codes w/ obdII

My car has 238000 miles.
My car has an automatic transmission.

With fuel issues such as these, there are a few things to consider first. If the fuel pump and all of that has already been replaced, then it is likely the issue is not with the fuel pump itself. The fuel system is controlled by the cars ECU and relies on the input from various sensors such as the oil sending unit and engine coolant temperature.

If any fault is found in the system, the ECU may not allow the fuel pump to run. The low voltage when cranking is a little strange, the most common cause of that would be that the battery is weak. If the battery is weak it may show 12 volts but will not have enough power to run any of the systems. A qualified technician will have little trouble diagnosing this battery fault firsthand and perform any repairs required to get your pump working again.

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: Ignition cylinder locked.

Hello, it sounds like you have a broken ignition key tumbler. A new tumbler will have to installed since the old one will get destroyed while being removed. Have a qualified mechanic replace your ignition lock assembly to fix the...

Q: My Car Won't Turn Over. What Is The Problem?

Hello. Thank you for writing in. To start, have you tried jump starting the vehicle? The clicking you are hearing is the starter trying to engage, but not being able to. This is either because the starter has failed, is...

Q: Sputtering, misfiring, power loss and gain

Hey there: There are usually two different mechanical problems that cause the symptoms you're describing with your Pontiac Firebird. The first and most common is a problem with the ignition coil, (especially in mid-90's GM V-6 engines) or due to...

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...