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2001 Buick Lesabre almost starts but won't


slyestdog
02-14-2013, 09:49 AM
I had this issue a month or so ago and after the car sat for a couple of days it started up and has ran fine until yesterday. My 2001 Buick Lesabre cranks over and catches for a second and almost starts, but doesn't. Someone suggested the fuel pump relay fuse, which I replaced and that isn't the issue.

I am assuming it is fuel related. I pulled the vacuum hose off the fuel pump regulator and don't see any gas in the line. How do I check the fuel pressure?

Tech II
02-14-2013, 10:02 AM
You attach a fuel pressure gage to the schraeder valve(under the black cap) on the fuel rail......

Or, you can spray carb cleaner into the throttle body while someone cranks the car.....ambient air should be over 32 F.....if it starts, you know you have a fuel problem....

Can also try disconnecting the MAF sensor and trying to start the vehicle....

slyestdog
02-14-2013, 10:35 AM
Thanks. I will have to go pick up a fuel pressure gauge. So I hook up the gauge, crank over the motor, and the pressure should read what? If it is low, I do I discern if the problem is the fuel pump or regulator? Could it be something besides those two?

I also have a 2002 Lesabre which I did swap out the MAF on to see if that was the issue, and it wasn't. On a side note, you said I could disconnect it. Based on that, I got the impression that if it was faulty and was disconnected, it should start. I did replace it a little while back. Before getting replaced, I almost got stranded because the car wouldn't stay running. If it is bad and gets disconnected, will the car be operable?

Tech II
02-15-2013, 12:42 PM
Fuel pressure should be 40-50 psi.....turn key to on....then shut off...wait 5 seconds, and repeat several times to get max pressure....and observe if it holds.....

I was just responding to your initial question.....the first place I would start would be checking for spark on all 6 cylinders......when removing boots from coil towers(one at a time), check for corrosion/black carbonning....if present, wires need replacement, and terminal(s) may just need to be sanded/cleaned, otherwise you need a new coil....

By disconnecting the MAF, the PCM goes into a backup type mode, and will attempt to start vehicle based on info from ECT, MAP, etc.

If the MAF is bad and hasn't fouled the plugs, and you have good spark on all 6 cylinders, it should start when disconnnected if fuel pressure is ok and the injectors are properly firing.....can be driven a short distance.....aftermarket MAF's are known for problems.....

If no spark at all, then it could be crank sensor or ICM.....

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