Replaced MAF sensor and converter overheated.

[spemb]

I have a 2001 Grand Prix GT 3.8L 3800 2nd Gen. I scanned the codes and it said "Mass Air Flow Sensor Low Input", this was the only fault code so I bought a new MAF sensor and installed it. I then erased the fault code and started the engine and drove about 1/2 mile and the car started to loose power and would barley move so I turned around and got it home. I got out and smelled the converter. I looked under the car and it was glowing red.

I took out the new MAF sensor and replaced it with the old one and was able to drive just like it was before, only problem is that sometimes on start-up the revs go up and down and then finally smooth out but never any overheating of the converter.

My question is, can a faulty new MAF sensor cause the converter to overheat like that? I know the MAF tells the PCM how much the air to fuel ratio should be. Seems like it was dumping way too much fuel into the cylinders.
Also I forgot to disconnect the battery cable before installing new MAF, could this cause the problem and it did not recognize the new sensor and did I damage it or my converter?

Any help will be greatly appreciated.

 

[Scottydoggs]

your cat was clogged up already. time to replace it.

 

[spemb]

Will I still need to replace with a new MAF sensor or just replace the cat?

 

[Scottydoggs]

just the cat.

if you got a aftermarket maf that maybe a issue down the road. these cars are no fans of aftermarket sensors.

 

[spemb]

Problem solved. The new MAF sensor was the problem. Had the exhaust checked and it was fine, also the converter was fine. The new MAF sensor caused the PCM to think it was getting more air than it was causing huge amounts of fuel to be injected which caused the converter to overheat. After buying another new MAF sensor the problem was solved. Now enjoying a 5 mpg increase in fuel economy and it runs and shifts so much better. No catalytic converter overheat.