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Anyone ever try Heated O2S on SPFI


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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.

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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.

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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.

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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.

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