thecobaltguy

How about my check engine light keeps coming on and i get P0420 wich is catalyst inefficiency....so i took it to the dealer for diagnostics and they told me that something is dumping too much fuel and is clogging my cat up....which in turn is popping this code....has anybody had this happen to them and if so how did they fix it....im thinking the tune should regulate the amount of fuel unless this is a crap tune i got from cobalt addiction...any help would be greatly appreciated.

ClearImageAuto Dan

A rich condition, too much fuel, can result from:

1. the tune
2. a bad O2 sensor
3. a problem with the MAF sensor
4. an intake leak
5. an exhaust leak (depending on where it's at)

You have some trouble shooting to do.

I hope this helps.

thecobaltguy

the dealer told me that something is dumping too much fuel and they told me there was nothing wrong with the 02 sensor... i haven't heard any leaks. im thinking it might be the tune

hackeragent061

i have the same problem my ignition control module was shorting out last month and was causin misfirin and dumping to much fuel through the engine and it just burned through the dp and most of the cat so i hav to replace the whole exhaust system now, until i do that i just keep during the code off and it usually stays off for a week or so b4 it comes bac on doesnt after performance or anythin, so u probably need a new dp or whole exhaust

elecblue06

iTrader: (1)

how long have you had the downpipe
?

thecobaltguy

i would say a year and a half maybe.

could the gapping of the spark plugs be too small so the spark isnt hot enought to burn the fuel..

MikeyB

P0420 is not because you cats cloged i dont think.

If you have a high flow cat, that would be whats causing the P0420

Its normal, many cars have that code when running a high flow. including mine.

thecobaltguy

i do have a high flow cat..i took it to the dealer and that is what the tech said after they put it on the diagnostic...the light keeps coming on and going off after a few days. is there a way to fix it so it wont come on i hate to see it on..drives me crazy cuz i think there is something wrong with the car.

383_Stroker

iTrader: (3)

Have that code set to not turn on the CEL in your tune.

thecobaltguy

so i would have to go into the tune to do that?

MikeyB

Thats just how it is with a high flow, dont listen to the "techs" there useless

Your car throws a P0420 Catalyst System Efficiency Below Threshold (Bank 1) Because the cat is not as restrictive as the cat that came on the car, the PCM is expecting a certain number that the stock cat produces.

The best way to fix this is get your tuner to turn off that code.

second best. Get one of the products that angle the o2 sensor OR (cant remember what there called) but they make the rear o2 think its in range

What i use, Interceptor. I just clear the code every other day or so