Need Some Help

[Dabear]

Okay.. So here are the basics, I have a 2001 2.4L with a WAI and pacestter header with the full 2.5in cat back system. I also put on a magnaflow high flow cat. Everything was fine until the rear O2 sensor went out. The car threw a code and started stumbling really bad. So I read the code and found out that the sensor went bad, so I replaced it. The code cleared, but the stumbling continued. I figured that it would hopefully smooth back out. Then about a week later it threw another code, this time for the cat. So i had it temp tested and it wasn't firing. I then pulled it off to find it full of carbon, really bad. It seems like I have been running really rich and it fouled the cat. So I need some help finding out why it is running so rich, and if this is what's causing the stumbling. Any suggestions would be greatly appreciated.

[spyhunter]

Okay.. So here are the basics, I have a 2001 2.4L with a WAI and pacestter header with the full 2.5in cat back system. I also put on a magnaflow high flow cat. Everything was fine until the rear O2 sensor went out. The car threw a code and started stumbling really bad. So I read the code and found out that the sensor went bad, so I replaced it. The code cleared, but the stumbling continued. I figured that it would hopefully smooth back out. Then about a week later it threw another code, this time for the cat. So i had it temp tested and it wasn't firing. I then pulled it off to find it full of carbon, really bad. It seems like I have been running really rich and it fouled the cat. So I need some help finding out why it is running so rich, and if this is what's causing the stumbling. Any suggestions would be greatly appreciated.

check your plugs to see what they look like...., could be fouled plug, bad coil pack, could be map sensor related, could be front o2 sensor related................make sure you don't have vacuum leaks.........

start w/ that.

[GA_turbo]

Okay.. So here are the basics, I have a 2001 2.4L with a WAI and pacestter header with the full 2.5in cat back system. I also put on a magnaflow high flow cat. Everything was fine until the rear O2 sensor went out. The car threw a code and started stumbling really bad. So I read the code and found out that the sensor went bad, so I replaced it. The code cleared, but the stumbling continued. I figured that it would hopefully smooth back out. Then about a week later it threw another code, this time for the cat. So i had it temp tested and it wasn't firing. I then pulled it off to find it full of carbon, really bad. It seems like I have been running really rich and it fouled the cat. So I need some help finding out why it is running so rich, and if this is what's causing the stumbling. Any suggestions would be greatly appreciated.



Well here is the thing now that you have the high flow cat your exhaust velocity increased and to top it all up, you went from a manifold that had the 02 sensor reading all cylinders to a header that only reads 1 cylinder. The sensor in the cat doesnt affect performance it just tells the computer that the cat is working, if your cat now is stright thru the o2 sensor in the cat is always goin to fry faster now cause now is reading higher temps that the sensor cant handel.
One thing you can do is wire your own heated o2 sensor for the o2 on the header and this will solve your running rich problem since the o2 sensor thats on your car right now is taking forever to heat up from only one cylinder, thats why you are running rich plus you are only reading one cylinder AFR.

[Dabear]

Well I replaced both of the O2 sensors at the same time, about 2 months ago, and the front O2 sensor is in the collector pipe so it should be getting all 4 cylinders, right? Also I just replaced the plug about 5 months ago with Bosc platinum 4's. And i just checked all the vac lines and it all looks good. And I didn't think the 2.4 had a MAP sensor only an IAT and that i think is okay..

[Cliff8928]

Also I just replaced the plug about 5 months ago with Bosc platinum 4's.

That's the first mistake. Waste-Spark ignition systems typically don't work good with bosch platinum series plugs.

[Dabear]

Really? What plugs should I change to?

[CBLOHM3400]

Ac Delcos

[nickbain]

ya man the stock ac delco are pretty good

[alerojack]

i like my NGK's personally... and they arent very expensive.

[GA_turbo]

That's the first mistake. Waste-Spark ignition systems typically don't work good with bosch platinum series plugs.



X 2 dont run bosch at alll........... never. Run some autolites youll be fine.

[Dabear]

Okay, I will change the plugs tomorrow.. Hopefully that will help.

[TheMeaningOfLife]

X 2 dont run bosch at alll........... never. Run some autolites youll be fine.

autolites all the way.:scpimp:

[CBLOHM3400]

i know that i said this before people buying nkg plugs are buying the samething as ac delcos
look at a ac delco and it has stamped on the metal part ngk
plus also has stamped the gm part number

[Cliff8928]

i know that i said this before people buying nkg plugs are buying the samething as ac delcos
look at a ac delco and it has stamped on the metal part ngk
plus also has stamped the gm part number

I think that's only the iridium plugs that are made by NGK for ACDelco.

[spyhunter]

NGK for the win.

[Dabear]

Okay.. So I went with the NGK Iridium IX.. It seems to be doing a little better, but I can still tell there is something wrong, still a slight trembling, and it just threw the Cat code again.

[spyhunter]

Okay.. So I went with the NGK Iridium IX.. It seems to be doing a little better, but I can still tell there is something wrong, still a slight trembling, and it just threw the Cat code again.

How many miles on car, have you had your injectors cleaned lately? Have you had your coil packs checked out at all?

[Spilner521]

What is the number that comes up when the code is read? That would help us help you.

[Dabear]

It's a 420 code, cat Inefficiency. It has 84000mi and I have run injector cleaner through it about every 5000mi or so. I haven't had the coils checked yet, I wanted to get some opinions before I spend $100 for a diagnostic.

[Dabear]

Okay.. So i got the diagnostic this morning. They said the main issue is that the upstream O2 sensor isn't heating up enough and that's causing it to run too rich. They said that the Bosch sensor that I just installed isn't good for the header and exhaust setup. They suggested that I go with a Delphi sensor and that should fix it. Also they said that the fan is turning on low sometimes when the car is cold. They said it shouldn't turn on until the operating temp, which is like 220, is reached. Its not always, but it might also be causing it to run to cold, which would cause it to run rich. I was wondering if any one has any input on this, or if any one has had similar issues? Any suggestions would be awesome.

[spyhunter]

Okay.. So i got the diagnostic this morning. They said the main issue is that the upstream O2 sensor isn't heating up enough and that's causing it to run too rich. They said that the Bosch sensor that I just installed isn't good for the header and exhaust setup. They suggested that I go with a Delphi sensor and that should fix it. Also they said that the fan is turning on low sometimes when the car is cold. They said it shouldn't turn on until the operating temp, which is like 220, is reached. Its not always, but it might also be causing it to run to cold, which would cause it to run rich. I was wondering if any one has any input on this, or if any one has had similar issues? Any suggestions would be awesome.

Bosch o2 sensors I have found suck. Go get the Delphi or AC Delco stock replacement. Or even find a Delphi or AC Delco heated o2 sensor from a GTP or whatever, and splice that into your harness so that once the ignition is on the o2 sensor is heating itself up before you even start the car.

[Dabear]

I couldn't find any places around here that could get in Deplhi or AC Delco, so I ordered one from GM parts direct. I was thinking about going the heated rout but I wasn't sure how much of a pain it would be. What other cars could I get one off of?

[GA_turbo]

Okay.. So i got the diagnostic this morning. They said the main issue is that the upstream O2 sensor isn't heating up enough and that's causing it to run too rich. They said that the Bosch sensor that I just installed isn't good for the header and exhaust setup. They suggested that I go with a Delphi sensor and that should fix it. Also they said that the fan is turning on low sometimes when the car is cold. They said it shouldn't turn on until the operating temp, which is like 220, is reached. Its not always, but it might also be causing it to run to cold, which would cause it to run rich. I was wondering if any one has any input on this, or if any one has had similar issues? Any suggestions would be awesome.


ok here is my question? how good are you with wireing or electronics?

here is the deal, the 02 sensor you had before the header used to work good cause the runners on the stock manifold were shorter and all the cylinders were able heat up the sensor faster and the manifold keept the sensor hott cause it was made of cast iron.
Now you have a header with longer runners so the sensor sits farther away from were it just to be, plus the header is made from a different material wich makes it runs alot cooler then stock.

Like i said above run a heated 02 sensor for the up streem and your problems are solved, its easy to do your self or if you cant here is what you can buy so that it would be even easier. Plus dont run iridiums they dont do anything for you but cost you alot of money, stick with standar oem style spark plugs.
http://www.casperselectronics.com/mm5/merchant.mvc?Screen=PROD&Store_Code=CEI&Product_Code=103025&Category_Code=

well this is the best i can do for you, the other choice would be put the stock manifold back on, problem solved.

[Vinalero]

GA_turbo, you should write some books like those XXXXXX for Dummies. Was reading all the tread and couldnt really understand right, I red yours and bingo.

So basically, a heated sensor tells the car that it is hot before it is (if that makes sense)

I found this interresting as I plan on putting a full headers to muffler setup in spring

[Dabear]

Thanks GATurbo.. I'm pretty good with electronic work, but I just spent $65 for the new OEM sensor. I'm hoping that it will work, but if I have to go heated I would probably go with caspers, that a good price considering the sensor is included. Do you have any input on my electric fan issues?
Again, thanks a lot for your help..