Hey Guys,

I've got a quick question on the Wells MAF sensor. I recently purchased one (on ebay), and installed it in my car. It will throw a Code 33 (MAF) every 3 or 4 minutes. I have reset the codes and disconnected the battery several times. The code always comes back. I can feel the car stumble and hesitate momentarily, the car will set the code, then the car will run fine for the next 3 or 4 minutes. Has anyone experienced a problem like this? Any ideas? I have not put the Tech 1 on the car yet (it's loaned out right now). I have a modified Bosch unit that I am running now, and the car runs fine as soon as I switch back to the Bosch. I just picked up the Wells as a "spare." Maybe the Wells doesn't work with my mods (see my sig.)

Thanks for any help you can offer.

Mike..........

maybe it is the mods or something, mine works fine and ive been running it for 2 months now, no problems. i had a modified bosch before i ran my wells to but the wells runs great for me. i'm nearly bone stock though.

You could try to change the TPS a little.........I had similar problem before and I increased my TPS and it fixed it........have ,58 v now.....

Thanks Guys. GTA324, thanks for the tip. My TPS voltage is indeed very low at part throttle (but is 4.55 @ full throttle). It has been low since I put the new motor in. It hasn't been a problem - at least until now. I will see what I can do to increase it some, although I have tried to increase it in the past with no success. It has no more adjustment. I'll have to take a file to the TPS body (like the Regal & GN guys do) to see if I can increase the range of adjustment.

Later - Mike........

Hey Mike, it sounds like you got a bad Wells MAF sensor. If it is throwing a MAF DTC, then the ECM is recognizing a fault in the sensor itself especially if swapping in the bosch unit fixes it. The reason why your car runs better when the SES light comes on is because the ECM bypasses the MAF signal when a MAF DTC is set and uses a table from memory to compute airflow utilizing TPS and RPM signals.

Hey MadMax350,

Well...........since the guy I bought it from on ebay was very specific about "no warranty on electronic parts", I guess I'm stuck with the unit. Is there a way that I could check the unit to see if it is bad (with a voltmeter, etc.) ?? I don't want to believe that it's bad (yet), however, I now have no idea what else to do. Thanks for the reply. I moved my TPS voltage up at idle to .62 with no effect on the sensor. I'll just "play with it some more" when I get a chance (it's back in the box now).

Later - Mike...........

Well there is no accurate way to test it with a voltmeter other than hooking up the voltmeter to your bosch unit, on the car, while it is running and measuring the output voltage on the green wire and then snap the throttle and see what it jumps to. Install the wells unit and do the same and compare results. If the sensor is in fact bad, then I would take the matter up with Ebay officials. If you paid via PayPal, you might be able to stop payment. No warranty or refunds on electrical parts should not apply to you as long as the auction had literature stating the unit was in working condition. Good luck.

i've talked to the guy a number of times, he's very helpfull and friendly. whether or not he would swap you a sensor i do not know though.

if i remember correctly the wells and the bosch do not put out the same voltage. yeah i found it the hot wire bosch uses 0-5 volts but the film wells maf uses hz, 32-150 hz.

i would try simply testing the maf on a buddies car who is basicly as stock as i am. mine works great! drives around just like normal and even made 2 dyno pulls last sunday. even after the dyno runs i drove home just like normal no changes at all. i've also pulled the intake off 3 or 4 times since i installed it with no problems.

Thanks Guys,

I'll get in touch with the guy I bought it from, and also the guy that burns my chips. Maybe one of them can tell me what I'm doing wrong.

Thanks Again - Mike.........