How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask carguyjosh Your Own Question
carguyjosh, ASE Certified Technician
Category: Buick
Satisfied Customers: 2172
Experience:  ASE certified, 16yrs working with buick
Type Your Buick Question Here...
carguyjosh is online now
A new question is answered every 9 seconds

2002 Buick LeSabre will not start. It cranks but doesnt even

This answer was rated:

2002 Buick LeSabre will not start. It cranks but doesn't even sound like it wants to start. Was running fine, then next time later that day went to go somewhere from being parked and it won't start. No trouble codes. Thought it might be the fuel pump. Fuel pump fuse good...swapped out relay with another the same...getting 5v power to the pump but not sure if 5v is correct or if it should be 12v. Not even sure if fuel pump is even a problem other than I don't seem to hear it kick on when the ignition is switched to "On" position.
The fuel pump wire is a gray wire, it should get 12+ volts so I would recheck that wire to see if there is voltage, this wire only gets power when the key is cycled on for 3 seconds. You should be able to hear the pump come on in those 3 seconds if it is working. Let me know the results and maybe I can help further.
Customer: replied 4 years ago.

The gray wire receives 12v when ignition is first turned on, then drops off within about one second or so. Never heard the fuel pump kick on. I had someone else turn ignition on while I watched from the trunk. Tried two more times with same results each time.

Customer: replied 4 years ago.
Relist: Other.
Expert is offline and I am currently working on my car and need help.

Good evening.

I see the tech is offline, what can I help with?

Thanks, Josh

Customer: replied 4 years ago.

Are you able to see the previous information I sent? My LeSabre will not start.


Yup, got it now.

So have you verified if it is indeed a fuel supply issue?

Have you checked for fuel pressure at the engine?

Thanks, josh

Customer: replied 4 years ago.

I haven't checked for fuel pressure yet - I will need to go down and get a loaner pressre gauge from AutoZone, but I thought I would try to verify power to the pump first. When the ignition is turned to the on position, I get 12v on the gray wire for about a second or so, then it drops back down. I never heard the pump come. Is thisd drop off supposed to happen?

I'll tell you what. If you remove the plastic cover over the engine and look at the fuel injection rail you'll find the fuel service port.

You can use a small screwdriver and depress the valve. If fuel sprays out, chances are the pump is fine..

Just let me know..Thanks, Josh

Customer: replied 4 years ago.

Okay, I think the port you are refering to is the one just to the left of where to fuel line goes into the from fuel rail (has a cap and looks liek the vlave on a tire). I depressed the valve stem and nothing at all came out.

Thats the one.

If no fuel is coming out and you have 12volts on the gray wire and ground on the blck wire to your pump, the pump is no good.

Please ask me anything that you need..

Thanks, Josh

Customer: replied 4 years ago.

Okay but just clarify one thing - the gray wire only had 12v for about one second, even though the ignition was still in the "On" position. Is that normal?

No problem.

The 1 second 12v. that you saw was the computer's command to prime the fuel system. The reason that it only primes for a second is that if the computer held the pump on, if you were sitting in your car with the key in the on position the fuel pump would kill your battery quickly.

This is completely normal..

Thanks, Josh

Customer: replied 4 years ago.

Thanks - the fuel pump (an aftermarket brand) was brand new 300 miles ago so it sounds like I got a bad pump. So I have one other question for you related to this problem... Is it possible that the problem with the fuel pump could be responsible for causing the two P0101 (MAF circuit) trouble codes I received earlier? Still not quite positive if that problem was actually solved or not.

Yeah, sound like the aftermarket strikes again.I've had it happen plenty of times.

As far as the MAF code. It likely has nothing to do with the pump. Because it is a circuit code its most likely a wiring problem.

Be sure to inspect the wiring connector and harness very carefully. I've seen many chafed wires on these cars..

Thanks, Josh

carguyjosh, ASE Certified Technician
Category: Buick
Satisfied Customers: 2172
Experience: ASE certified, 16yrs working with buick
carguyjosh and 3 other Buick Specialists are ready to help you

Related Buick Questions