2000 LeSabre starts very rough, then dies. Intermittent.

[GWBridge]

My wife got stuck with the 3800 Buick while I was out of town. Said it would start and run for a couple of seconds and die. I had replaced the fuel filter with a new one very recently. Got home, and the car started right up and drove to a better position in the parking lot. Towed it home, got it off trailer running pretty well. Within about 30 seconds it was barely running and just made it into the driveway. I shotgunned the problem and installed a new fuel pump. Engine started right up, ran reliably and strong. Went out next day, and we were back to not wanting to start and run. When it does barely start, it runs very rough and seems more like an ignition timing issue than a fuel issue, so I've been thinking crank sensor.

The engine isn't throwing ANY obd2 codes at all. At the moment, I am thinking crank sensor and/or maybe fuel pressure regulator.

Any advice on what might be the cause or how to troubleshoot this would be greatly appreciated. I tried searching but haven't found similar symptoms.

- Cleaned throttle body a few months ago. Has been running well up until now.
- Installed new fuel filter a few weeks ago. Ran fine after that.
- Just installed new fuel pump as described above.
- Zero OBD2 codes showing. Maybe hasn't run long enough to be saved?
- Will look at and clean MAF, but it doesn't seem as if that's the cause.
- Spray starting fluid into the intake to see if it's lack of fuel or no spark?

 

[02LTD2.0]

How many miles are on the car?

 

[02LTD2.0]

Possible flaky ICM.

 

[GWBridge]

119k miles. Hoping it's not an ICM. Intermittent nature seems consistent with bad electronics, though.

Actually, after reading up, I think the ICM would be the logical place to start, but it will have to be an aftermarket one at that price for OEM.

Thanks very much for your valuable input.

 

[02LTD2.0]

119k miles. Hoping it's not an ICM. Intermittent nature seems consistent with bad electronics, though.

If you are near a pick-n-pull junkyard you could swap one in and see if anything changes. A 5.5 mm nut driver is all that you need to remove the coils.
7/32 will also work.

 

[Homer Jay]

If there's no spark the ICM is likely bad.
If there's spark, the MAF sensor may be bad, especially if it's a poor quality replacement. Next time you have a no start or poor running, disconnect the MAF sensor.
If there's an improvement, replace MAF sensor with an OE equivalent (Hitachi)

 

[Chris01]

Came to say this. I’ve had two Lesabres with similar symptoms. Neither threw a code. Both were faulty MAF sensors. I carry a spare in my glovebox now.

 

[02LTD2.0]

Came to say this. I’ve had two Lesabres with similar symptoms. Neither threw a code. Both were faulty MAF sensors. I carry a spare in my glovebox now.

Just curious, what brand of MAF?

 

[Chris01]

Just curious, what brand of MAF?

I replaced one with a Delphi and one with a Hitachi.

 

[GWBridge]

Just a quick follow up. It was the MAF sensor in the end, though I'm not sure I didn't have multiple issues since the symptoms change to only running for two seconds to running steadily but rough. Started with the ICM. Ohmed out the coils and they seemed good. One was really rusty where the plug wire attached. Weird. Cleaned that and the wire up. This seemed to not have any effect on the main problem. Moved on to the crank sensor. Pulled the harmonic balancer and replaced the sensor and also replaced the crank seal (major pain to pull the old one and get the new one in properly). Put it back together realized that I had forgotten to replace the plastic shield behind the pulley. At this point, the engine continued running but was very rough. Pulled the harmonic balancer again (amazing how much easier things are the second time you do a job). Pulled the plug on the MAF sensor, and the engine smoothed out. All seems to be running well, now. Perhaps better than before.

Ordered valve cover gaskets, grommets, plugs and wires.

 

[02LTD2.0]

I hope you're going with an OEM sensor, in other words HITACHI.

 

[GWBridge]

I hope you're going with an OEM sensor, in other words HITACHI.

Hitachi MAF0047 Mass Air Flow Sensor $72 on Amazon​

Live and learn. I should have unplugged the MAF sensor first, but I was sold on it being the crank sensor because it would run for a couple of seconds and then die. When I checked the MAF, it was running steadily but roughly. So, I spent money on parts I didn't EXACTLY need, but maybe there's some sort of preventive maintenance benefit there. It certainly was a learning experience.

 

[02LTD2.0]

I bought my Buick 5 years ago with a P0102 code on it. I ordered my HITACHI MAF from Amazon and haven't had any issues since then. Money well spent.👌