Hey, all. I'm having a quite crippling problem with my catalytic converter. I cannot seem to find one that properly fits. Autozone offers two direct fit converters. The one I ordered is too short in overall length and the inlet ports are a few inches too short, so they'll never reach the exhaust manifolds. The second model offered looks more correct upon inspection but it has one catch: there are two ports for my oxygen sensor, but my cat only has ONE on it. There is only one O2 sensor, which is downstream. The other two sensors are located on the exhaust manifolds, NOT part of the catalytic converter piping. Summit Racing offers the same two models, and every where else I check. I cannot seem to find the proper size direct fit application. Does anyone have any ideas? Perhaps I'm looking in the wrong spot, or perhaps GM put a few oddball converters in their 1998 model 3.8s?

 

is it a cali emmisions car? just did my cat and it was in the end after trying 3 diff cats here in nj

 

how short was the first one ? maybe you can cut some pipe to lengthen it

 

If the second cat fits, try to find a bolt that you can use to plug the forward oxygen sensor hole. That's probably what I would do.

 

OBDI,1995 and older,cars have one set ofO2 sensors installed ahead of the cat (could be one or two sensors depending on model), these are the upstream sensors which control the A/F ratio.
OBDII cars, 1996 and newer, have 2 sets of sensors, a set of sensors before the cats (upstream) to control the A/F ratio, and one set after the cats (downstream) to check on the upstream cats.
If the second cat you got fits, but has 2 sensor bungs, insert your sensor in the bung on the inlet side of the cat, and plug off the one on the outlet side of the cat.

 

Hmm, if it does indeed fit, without being hostile, why would I plug the one after the cat? The system on my car has a post cat sensor now, so shouldn't I keep it the same?

 

I understood that you only had upstream sensors, didn't pick up on the car year, my bad. If it fits , then just do as BryantD described.