I have an 95 Z A4 with a dual cat and OBD1 as well, or at least it used to.....

 

If you have an OBD1 scanner with the 12 pin connector, use this diagram to adapt it and it will work fine.

 

cali 95 z's (own j00)

 

My brother's 95z a4 has dual cats as well. So does my other brother's 94z a4 convertible

 

Stupid question, but what does a cat look like? Also I emailed tom at tbyrne motorsports about this and he said:


"Most '95s that we sold in CA have dual cats. If you have a large converter under the passenger's side floor that means you have a single cat. A small converter there and one up high on the driver's side will be for a dual cat car".

Hope this helps,
Tom


I have a large coverter under the passenger side floor so i guess i have a single cat. I have a m6 also.

kyzer soze

 

The one he refers to on the driver's side would be just after the flange at the exhaust manifold in a semi vertical position as the pipe is going down.

 

Could someone post a photo of the exhaust system of a 95 with dual cats?

 

Look at any 96 or 97 LT1. Same system, just installed a year early on California emissions A4 1995’s. Should be diagrams in the 96 factory service manual.

https://www.mediafire.com/?40mfgeoe4ctti

I was living in California at the time, bought my 1994 Formula brand new in August 1994. When the 95’s came out I was a pest at the dealers actually occasionally crawling under the new models, and very clearly remember the dual cats on a 95 A4 LT1. 95 M6’s kept the single cat because they were all 50-state emissions compliant. My car had the CA emissions RPO YF5 but at no cost. The A4 models in 94 and 95 had $100 added to the cost for YF5. It was never really clear to me why only the 95 A4 required the dual cats, when there do not appear to be any significant differences between 94 and 95.

 

I don't have a 96 or 97, which is why I asked if someone could post a photo. A picture is worth 1000 words.

 

Interesting. The 96 manual shows a cat just downstream of the left exhaust manifold. The other one appears to be on the right bank, just before the y-pipe junction. The diagram seems to mislabel the right one as a pipe. Is this how the dual cat system looks on the 95 A4 cars?

 

That's about it. Same as described above, e.g. Shoebox's post #21.

Sorry my response didn't meet your needs.

Part 2 points to an assembly that includes a 2 flanges, multiple pipes, expansion joint, and a catalytic converter. Apparently that's what you get if you order a catalytic converter from GM.

 

I know this is a super old thread but my car is the same way. Did you ever actually do anything with the cats as far as removing them? One of them is pre-o2 sensor so I'm not sure if it's going to cause any issues but the car is still OBD1.

 

“1msfyter” hasn’t signed in to this site since 2011 (14 years ago to the month).

OBD-1, including the 1995 A4 LT1 cars only use pre-cat O2 sensors. There are no after-cat sensors. So removing the single cat or those from a car with the dual cat setup will not set a code for the missing cat(s). There should also be a pre-cat sensor on the PASSENGER side. It's required to provide closed loop feedback to the PCM. Look higher up on the down pipe from the manifold.

Just to clarify…. does “my car is the same way” mean you have an A4 dual cat setup?

 

Yes, because it's originally a California car, it does have one cat just after the driver side exhaust manifold that is just upstream from an O2 sensor. Then, there is another cat in the exhaust about halfway back that is downstream from an O2 sensor.

 

I mis-typed my previous post. I thought you found the driver side pre-cat, but you appeared to indicate only one of them had a pre-cat. I was trying to tell you where to find the passenger side pre-cat. I'll edit/correct my error.