A while back I had the 14x3 AC mod before I got the Magna-Flow cat. Other than the sucking noise (on initial startup that I hate) and loss of bottom end, I had no probs.(CEL etc..) But, I put the OEM intake back on anyway(no noise and bottom end a lot better). Then I got the MF cat.(direct fit, y pipe and all) a few months ago. Again, no problems(meaning CEL) with 02 sensors. For anyone that might remember (in a previous thread), last week or the week before I decided to give the 14x3 another chance. Well since then, I keep getting a CEL code PO138(downstream 02 sensor shorted or whatever).

So for anyone interested, I will be putting the stock air intake back on, to see if there is any change.(and yes, both 02 sensors are new).

I guess I'd like to know if anyone thinks there is a direct correlation between having both these mods and some kind of A/F ratio problem.

Sorry so long and Thanks for reading, John

 

you reset the computer ????

 

I have both on my 5.2 and have never had any codes like that.

 

Same here. and then eventually changed my o2's anyway because they had 100,000 on em.

 

Yes I reset the PCM. And 2 minutes ago I plugged in my OTC Genysis to check the code for the heck of it, and now I'm getting the codes for both 02's. I cleared the codes and ran it for a few minutes and nothing. I have to use the truck tomorrow so we'll see. And both 02's are new as of a couple months ago when I installed the Magna-Flow cat. I'm hoping that this is not a side effect from using MMO in the gas.

 

Zman,

I've had no problems running the magnaflow cat and muffler with that round TB. I can't imagine you're having an issue with A/F due to those two items.

How much MMO you been putting in and for how often? Does it say anything about potential damage to cats on the bottle?

You might have coated the O2's with some crud. You can pull them and try to clean them with CRC electric parts cleaner. What O2's did you go with? I've heard of guys having bad luck with bosch O2 sensors.

 

what o2 sensor you put it ???

 

I use 4 oz. per 10 gals fuel every other time I get gas.

And the 02 sensors are SMP.

 

how long you been running the MMO and how often do you fill up?

The official Mopar fuel injector states to only run it once every 2500 miles maximum. MMO works pretty much the same way as fuel injector cleaner IIRC. If you've been using it once every 275 or so miles, and frequently depending on how far you drive, there's a possibility you have damaged the cat.

I'm a fan of the OEM NTK O2's at rockauto.com. That place is cheap if you've got a big order and the patience to wait on it.

 

Thanks for your honesty.