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Discussion Starter · #1 ·
I have a quick question about my 1JZ and the stock O2 sensor. I have a '89 Turbo with a JZA70 1JZ swap about to be completed. I'm going single from the get-go and using a MAP-ECU2 for tuning. On the MAP-ECU forum most users say to leave the O2 sensor unplugged so that the stock ecu won't continually fight the MAP-ECU2. I'm afraid this will cause the car to go into "limp" mode and I don't want that. I'm thinking I might try leaving the O2 sensor plugged in but securing it in the engine bay outside of the exhaust. I'm thinking this may cause the engine to read "stoich" which will cause it not to try adding or subtracting fuel and make tuning easier. The only thing I'm worried about is whether the engine will think something is wrong when it's still "stoich" under boost. I don't know enough about open and closed loop I guess. That's where I'm hoping somebody can chime in. Any suggestions would be nice. I've tried searching but haven't come up with anything yet. Will this work?????
 

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Discussion Starter · #3 ·
I know, that's why I'm contemplating leaving it hooked up but outside the exhaust. Theoretically, it would read atmosphere (I'm pretty sure 14.7) all the time causing it to throw no codes, no "limp" mode, and also causing it not to try changing the fuel map once I tune it with the MAP-ECU2. I should also mention that I am using an AEM Uego to monitor AFR's and also hooking it up to the MAP-ECU2 for logging and tuning.
 

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one question / suggestion.

Will mapecu read wideband signal from uego? If so, can you program an output from mapecu for narrowband to stock ecu? If so problem solved.

Im going through this now as well, damn uego with no narrowband output!!! FUKKERS over at aem... i know just what they were thinking (those suckers have to get aem now to get their narrowband output) ass-masters.
 

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Discussion Starter · #6 ·
I know the MAP-ECU2 will read the UEGO. It also has a O2 adjust feature that I believe does what you describe but I'm trying to avoid having to tie into or cut any shielded wires. It's looking like I'm going to have to just try it and see what happens.
 

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I definately would not just leave it out of the exhaust because there is a hell of a lot more o2 in the atmosphere than in the exhaust so it would be reading all of the o2 in the atmosphere making the computer to think its lean and therefore the computer would try to richen it up.
You need to do a lot more research before you do this yourself, If you just want it to be done and done right take it to a good shop.
 

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Discussion Starter · #8 ·
Ok, this is where I must have been clearly mis-informed. I always thought that atmosphere was stoich. That if you took an O2 sensor and let it read the atmosphere that it would be 14.7. If that's not the case then my idea is dead on arrival. It's looking like I'm gonna just have to put it in the exhaust and start cutting and splicing shielded wires. Thanks for the input guys!!!
 
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