need your help

[turbohawk]

i have a 1997 grand prix gtp,i was getting a rough running problem and a p0102 dtc(maf circut low voltage).

now on the scanner it wasn't reading anything on the maf reference,so i tested the wires, it has ground,it has its 12v reference,but on the yellow wire it was only reading 2.70 volts.

when it would drop to nothing on the scanner the yellow would got to 11.25 volts,i replaced the maf and just for giggles i ran a new yellow wire and pin from the maf to the pcm,worked for about 10 mins and did the same thing.

i tried another new sensor,again 10 mins and the same,if you drive it good it works ok,as soon as it see's any boost or more or less anything over 10 lbs it does it real bad. a

the pcm is another one from another 97 that was flashed by intense racing for my mods.i cant figgure this out please help!!!

[BNaylor]

Welcome to AF.

Whatever generic code description you are using is misleading. The PCM module looks for a certain frequency not voltage that the MAF sensor generates based on airflow and throttle position. 1500 Hz to 10500 Hz. Your MAF sensor is putting out less than 1200 Hz. In GM talk P0102 is "MAF sensor circuit low input".

The yellow wire pin A at MAF electrical connector is the output of the MAF going back to the PCM module as "MAF sensor input". However, the PCM has detected a frequency of less than 1200 Hz triggering the P0102 DTC.

The ignition circuits provide a 12 volt reference signal at the pink wire pin B that the MAF uses. The black/white wire pin B is ground. But from what you are saying those are good.

From my experiences a P0102 DTC is caused by a flaky MAF sensor. I suggest you get a known good MAF sensor. What brand replacement MAFs did you use?

[turbohawk]

i used a standard,and a cardone,and a factory one that was working fine when it came out of the car

[BNaylor]

Originally Posted by turbohawk

i used a standard,and a cardone,and a factory one that was working fine when it came out of the car

I see two problems off the bat. The Standard and A1 Cardone MAFs leave a lot to be desired. Especially the Cardone since they are remanufactured. As far as the original one it sounds like it went South for whatever reason. It is not uncommon to go through several MAF sensors until you get a good one. Also, make sure it is for your year model and engine. For example a MAF from '99 and up will not work on a '97 - '98 model and vice versa.

In most cases what will resolve the DTC is a new GM MAF sensor. It is a simple circuit. 12 volt reference signal, airflow detected at hot wire element sent to the processor within the MAF and MAF then generates the proper frequency signal based on throttle position to the PCM module.

The only other possibility I see is the MAF may be generating the right frequency but the PCM does not see it and not accepting it switching to the pre-programmed MAF/VAF tables.

Also, do you have a CAI/FWI installed?

[richtazz]

Welcome to AF

I agree with bnaylor that the Cardone brand MAF's are questionable at best. I would avoid them. The Standards are better, but still not as good as OEM. Anything but GM/Delco, and you're asking for trouble. If you have a K&N style air filter installed, you have to be VERY careful when oiling them, as excess oil will muck up the MAF (I believe that is why bnaylor asked about the CAI/FWI).

[turbohawk]

yes its a fenderwell intake,and all 3 mafs did the same exact thing so im stumped

[BNaylor]

Originally Posted by turbohawk

yes its a fenderwell intake,and all 3 mafs did the same exact thing so im stumped

What brand FWI?

However, I doubt any filter oil caused the subsequent MAF sensors to go bad. From what I can see you are probably looking at your problem. It looks 50/50 between the MAF sensor or the PCM module.

When you reset the DTC with the scanner how soon does the P0102 code set?

[turbohawk]

Originally Posted by bnaylor

What brand FWI?

However, I doubt any filter oil caused the subsequent MAF sensors to go bad. From what I can see you are probably looking at your problem. It looks 50/50 between the MAF sensor or the PCM module.

When you reset the DTC with the scanner how soon does the P0102 code set?

as soon as it warms up a lil and sees boost

[BNaylor]

Originally Posted by turbohawk

as soon as it warms up a lil and sees boost

Some more questions. Do you have the throttle body screen installed or removed? Also, what brand FWI is it? Name brand or whatever?

[turbohawk]

Originally Posted by bnaylor

Some more questions. Do you have the throttle body screen installed or removed? Also, what brand FWI is it? Name brand or whatever?

the screen is installed,and im not too sure what brand it is,there is no markings,its dark grey though with black silicone connectors

[BNaylor]

Originally Posted by turbohawk

the screen is installed,and im not too sure what brand it is,there is no markings,its dark grey though with black silicone connectors

Ok. Try this. With your scanner clear the DTC and SES light, if any.

Unless you have already done this, remove the electrical connector to the MAF sensor and take it out for a test drive. See if you still have the rough running. The idle will be erratic until the engine warms up.

[O.I.F.Veteran]

Originally Posted by bnaylor

Ok. Try this. With your scanner clear the DTC and SES light, if any.

Unless you have already done this, remove the electrical connector to the MAF sensor and take it out for a test drive. See if you still have the rough running. The idle will be erratic until the engine warms up.

Hey men, I have the same exact problem with my 97 GTP and I've try everything like the others even replacing the MAF sensor. Now, on this instructions you gave, should i remove the throttle body screen as well as the MAF electrical connector??? Thanks.

[O.I.F.Veteran]

Originally Posted by bnaylor

Ok. Try this. With your scanner clear the DTC and SES light, if any.

Unless you have already done this, remove the electrical connector to the MAF sensor and take it out for a test drive. See if you still have the rough running. The idle will be erratic until the engine warms up.

Besides removing the MAF connector, Do I need to remove also the throttle body screen??? Thanks.

[BNaylor]

Originally Posted by O.I.F.Veteran

Besides removing the MAF connector, Do I need to remove also the throttle body screen??? Thanks.

No. Leave the TB screen in place.

[O.I.F.Veteran]

Originally Posted by bnaylor

No. Leave the TB screen in place.

Thanks. Anyway I've try it as you said so but nothing happen, the car still doing the same . Just so that you know I've also replace every gasket all the way from the lower intake manifold and up to include new PCV Valve, throttle body, supercharger to lower intake manifold, and every single gasket in the way. I know it has nothing to do with the problem but i also replace the supercharger and installed a smaller pulley (3.4"), right now the only probable thing left is the ECU, ECM or however you want to call it, because i've done everything. But anyway, beside everything i've change, is there anything else that i'm missing??? The only thing left is to light the car on fire lol . Thanks again very much for your support.