TheSamba.com :: View topic - '79 2.0

Fri Jan 17, 2014 12:04 pm

I have a '79 Cali 2.0 Westy that's in dire need of a new muffler. Last year, I backdated my heater boxes to the earlier style ('72-'74) to eliminate the cat and associated – clogged – plumbing with good results.

At that time, I had an 02 bung welded into the muffler above the #4 inlet, which seems to be working fine. Now that the muffler is shot (it was old to begin with), I've seen some mufflers that have an EGR port in very near the same location as the existing O2 bung. Would there be any issues with relocating the 02 sensor to that location? Seems like an elegant solution to me... Am I missing anything?

Fri Jan 17, 2014 12:11 pm

O2 sensor has to be in the exhaust stream. If you can make that work go for it.

Fri Jan 17, 2014 12:23 pm

And an EGR sensor would also require placement in the exhaust stream, correct? Just trying make sure I'm thinking about this the right way. Thanks!

Fri Jan 17, 2014 12:29 pm

If you go in above the flange on the 3-4 side you are only reading those two cylinders. Don't know what you get if you use the position of the EGR port. I have welded in a bung for an O2 sensor on mine into the tail pipe right where it leaves the muffler. I haven't hooked it up to my analyser yet to know how it will work, I hope it is far enough up stream from the end of the pipe not to get any back flow.

Fri Jan 17, 2014 1:12 pm

The tailpipe is an interesting location, too. I think I was afraid of the same backflow issue you mentioned, but in thinking about it more it seems like there would be enough constant exhaust pressure to negate a false read. Sure would make the 02 sensor more accessible, too.

That said, my current O2 sensor is more accurately located above and off to the side of the 3/4 inlet; my thinking was that location would read more accurately than directly above the inlet.

Fri Jan 17, 2014 2:13 pm

What are you using the O2 sensor for currently? Is that connected to the stock computer, so it can automatically adjust your mixture for you - the way they intended for a 79CA bus?

If so id consider ditching it completely, unless you need to smog still (and then id just weld in the bung and connect it only when smogging it.) The stock 79CA AFM, if it hasn't been fiddled with, connected to the O2 sensor will make the engine run VERY lean.