GeorgeC

I have a stock car now, and can't even keep it running right!

Lately my T/A has been intermittently falling on it's face during part throttle acceleration, and has also "hiccupped" a few times during normal part throttle cruising. Now it's gotten worse, and the SES light has come on. Since I no longer even have Autotap, I was forced to go to the local Autozone and have the code read. It's a MAF code (but I didn't get the entire DTC since I wasn't thinking clearly enough at the time), and a Bank1 and Bank2 lean codes. The car now feels totally flat at part throttle, and doesn't feel quite right at cruise either.

With the car running, I can remove the connector from the MAF and get zero change in the way the car is running (idling) at the time, so I'm almost positive that the MAF isn't functioning at all, and the car has defaulted to speed density mode. With the engine off, key on, I do have 12v at the pink wire on the MAF (like it should be), but I don't have a wiring diagram for a 2001 so I haven't checked for continuity between the MAF signal wire and the PCM. I'm really leaning towards a bad MAF at this point, though.

I've pulled the PCM BATT and PCM IGN fuses to clear the SES light for now, and will have another stock MAF to borrow shortly, but I will only have access to it for a short time.

Any advice at this time on how to tell for sure whether the MAF is bad? I sure wish I had kept my Autotap software now. I don't know any local folks that have any type of scantool I can borrow.

One last question... On a normally functioning car, should it not stumble some and try to stall (at least momentarily) when I unplug the MAF with the engine running?

SilverGhost

iTrader: (53)

gonna have to try that other MAF, get the codes cleared out and see if the problem returns..that would be the easiest/fastest way to know if the sensor is crap or not..

jimmyblue

iTrader: (11)

Read voltage at the MAF connector, one pin should be +12V,
one +5V (orange, pink I believe). If these are down, that's your
problem.

If voltages are up, the "+5V" wire should also have about 2500Hz
on it at idle.

GeorgeC

Well, now things get interesting (and confusing). We swapped MAFs, and both cars ran fine (obviously we weren't able to put too many miles on them, though). After swapping back, my car is still fine, and no SES yet.

I'm going to drive the car to work for the next couple of days and see what happens...

Another_User

Maybe you threw a MAF code and it took awhile to reset. That would be normal. It would run off the VE table (like poop), and then after awhile it will reset (x number of successful tests). Your MAF may be slightly out of spec, or it just needed a chance to reset. If the problem does not happen again you should be fine.

Louis

iTrader: (7)

The pins in the MAF are a little sensitive. They can appear to be connected, but further inspection may reveal otherwise.

Plug in ATAP, or what ever you have and see what the MAF is reading in Grams/sec. That will be the ultimate factor.

GeorgeC

I've had trouble with the pins before (on the '98), so I know that's a possibility.

Unfortuantely, I sold my Autotap stuff back when I decided to ditch the LS1 and put a carb on the '98... I never thought I'd go out and buy another stock LS1 car... You know what they say about hindsight...