OBDII question

[vwmann1]

I'm been looking for my car for sometime now and I have been only looking at 93-95. The reason is they are OBDI so there is no O2 sensor after the cat. My question: Is there a way to fool the after-cat sensor so you can pull the cat.If there is I can open my search to OBDII cars.

[Knestis]

I'd love some informed input on this subject as well. In hindsight, I wish that I had an OBDI car, too - they are easier to license in NC. http://Forum.ImprovedTouring.com/it/smile.gif

K

[Dave Zaslow]

There are devices meant to fool the system into thinking the cat is there. They send a regulated signal (voltage) to the ECU. Look at the bottom of this page: http://lt1f-body.racenet.net/headers.php for such a device. Then start googling for more.

Dave Z

(who decided an obdI was going to be easier to deal with)

[vwmann1]

Thanks for the info.
I think the OBDI will be easier because it does not monitor as many points. Things like the evap system, second O2, leak detection system, things that OBDII does monitor. This is all stuff typically taken off the car in the build up. I don't know maybe I am thinking too much. I sure there will be many cars running around with the MIL on.

[JOESELLSVW]

" a lot of cars will be running around with the MIL light on" well yeah, it is a VW afterall. Aren't Check Engine Lights normal? HAHA! Seriously though, I like this thread..... especially since I have a 96 GTI ITB car. Although this is a little farther down the development pathway for me as I still have my AC and spare tire in the car! Anyone going to MARRS 9? Joe

[Bill Miller]

Hey Joe,

Can you get in touch w/ me re: getting those parts to/from VIR.

------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608

[Knestis]

Doing the sunroof Sunday, Bill but I'm having concerns about the exhaust. Since we last talked, I ran an HPDE and the exhaust is getting that raspy VW blown-out muffler sound...

K

[Eric Parham]

Interestingly, it has been suggested that I convert my OBD1 95 ITB project over to OBD2 due to a better intake manifold. I won't do it unless I can see/evaluate the difference for myself. I'd also have to carefully think through the "engine assembly" rule before proceeding.

I was going to try to avoid the computer issues for at least the first year. I have already tried one of those o2 simulators for the second o2 sensor out on a 97 VW, and it didn't cut the mustard (although it was later reported to have worked fine on a 96 by a subsequent owner).

I think that the o2 simulators mostly use a timing circuit to simulate what a downstream o2 would report *if the upstream o2 was keeping the engine at stoch*. As soon as that assumption goes away, at least the later computers may notice the deception.

I think a slightly better method might be to match the min/max readings of the downstream o2 to those of the upstream unit, but maintain the downstream signals for longer durations.

Of course, if we could figure out how to patch the computer's flash memory, none of that would even be necessary...