01 lesabre MAF causing no-start

[eljefino]

mother in law's 3.8 lesabre MAF went crummy a couple times... code was IIRC p0107, MAF reading low. Cleaned it a couple times over the years then replaced it with an advance auto rebuilt a couple days ago. Not our first choice but we could get it ASAP last weekend. Worked for a couple days, in fact the car ran better than it had in a while.

Just now this new MAF sensor wouldn't let the car start. Unplugged it; started the car, plugged it in, kept running.

Am trying to diagnose this thing over the telephone as I'm stuck at work, LOL.

Seems real odd to me that it relies on MAF readings for cranking... think they should just look at throttle position and coolant temp... but there you go, it blocked the car from starting.

Wiring looks 100%, anyone know if the MAF sensor communicates digitally (eg pulse width, frequency etc) or via an old-school variable voltage to the PCM?

I have a scan tool that shows grams per second of air going by but of course it's not with the car at the moment. Besides, we all know the MAF/PCM is seeing little/no air, just trying to figure out why...

 

[brianl703]

Try disconnecting the battery to reset any bad fuel trims it may have learned from the old MAF.

GM MAFs normally use a frequency.

 

[MrCritical]

Now go get a REAL MAF.

 

[artificialist]

Pull the plug out of the MAF, and the engine will use the MAP instead.

That usually works.

 

[globey]

Originally Posted By: MrCritical
Now go get a REAL MAF.


What's wrong with the MAF he purchased and how do you know OEM isn't purchased from the same manufacturer?

 

[MrCritical]

Autozone/Advance electronic parts are not known for their reliability.

He already said the MAF wouldn't let the car start.

 

[globey]

Well, AutoZone carries the Cardone remanufactured MAFs and I can tell you I haven't had a single return on them.

Wells makes most of their electronic parts and they also supply a lot of OEM parts to various manufacturers.

He may have gotten a bad part but to say he doesn't have "a real MAF" might be stretching it a bit.

 

[MrCritical]

I don't think Cardone builds fuel/emission parts for AC/Delco. I could be mistaken.

If they do/did, they would be to a much tighter spec/tolerance than what they build for AutoZone.

The Zone has many good parts, however reputation wise that doesn't include alternators, starters, ac compressors or electronics.

 

[rationull]

Years ago my dad had a problem w/ the MAF or MAP on his '88 LeSabre w/ the 3.8 engine. I can't remember whether it was the MAP or MAF, and I can't remember what the symptoms were, either. He went through 2 or 3 sensors that all worked for a while and then seemed to stop working again.

IIRC it turned out that the problem was actually some wiring that had rubbed bare or something similar that was contacting metal parts of the body or engine and shorting out.

I'm sorry I can't provide more detail but I just wanted to throw that out there.

 

[artificialist]

My dad's Lexus ES300 once had the MAF sensor die. When he stepped on the accelerator, the engine would stumble for 1 second, and then accelerate. That was at 37,000 miles. The replacement was covered under the longer emission control warranty, and was done for free. The replacement MAF lasted to 160,000 miles when dad sold the car, and for all I know it is still going.