Anyone out there still running w/SPFI ea81? Im wondering if there would be any real benefits (worth the time and $$$) to try a 3 or 4 wire o2 sensor. I was watching my O2 lamp and I started to get the feeling I *might* see some MPG increase with this mod.

I tried a 2 wire on mine and the added ground alone helped. Someone else reported back that they were running a heated one and it works even better. I can't remember who but it has been done. I say go for it!

I dont care for the bosch O2S's but I have an extra 3 wire that should fit... Anyone say ya or nay for bosch on these cars. Still like to hear some more results on this befor I play...

In this thread someone mentions trying a heated o2. Perhaps try and contact them?

 

SPFI O2 Ground

Yea I did see this thread. I always search befor I post. I may PM him and see what his gains are. I might just do it its not that big of a deal to wire up.

i added a 3 wire heated O2 sensor on my MPFI turbo GL. i took the cat out of the down pipe and my O2 went flat at idle and would not pass WA emissions.

 

i put a heated sensor in and it passes emissions without any issues.

 

-=Suberdave=-

www.suberdave.com

It will have NO benefit on mileage or performance. The heater is there strictly to bring the system into closed loop mode faster on startup and reduce emissions. As Dave pointed out, if you have an emissions issue, it'll help. Basicly, if you reduce the back pressure too much, the O2 sensor won't be heated properly by the exhaust gas and thus will not read correctly. Add the heater and all is well and happy.

I have a Bosch 3-wire in my '94 EA82 SPFI, and a potentiometer across the coolant temp sensor to tell the computer the car is warmer than it is, all to get it into closed-loop sooner for better mileage.

 

Before I did this, hitting my injector kill switch the car would keep running for 2-3 seconds when cold (uber-rich). Now, it dies within 0.5-1 second, without losing driveability in open-loop. I think it was too rich in open-loop warmup anyway.

It will have NO benefit on mileage or performance.

What Im noticing is that it takes a bit to go into closed loop, and if you set at a idle for a bit sometimes it kicks back into open loop. This should have very little impact on driveability, but I get the feeling it does shave off MPGs.

Honestly my biggest debate with this is spending money/time and making a headache when there is nothing wrong with the car. I have a newer NGK sensor single wire in there now, I could throw in a Bosch 3 wire I have lying around, I just hate the Bosch units. I let you guys in on my results after I get it done and run a few tanks through.