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Discussion Starter #1
finally finished up the exhaust on the 20v. prior to this however i was using the 20v b-pipe with its o2 sensor. now i am using a pipe with a 16v o2 sensor in it, and it would be very difficult to remove it. i am thinking it would be simpler to just rewire the 16v one for the 20v plug? anyone done this that can remember how to match the 4wires together?
 

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Run the 20v one
cut the 20v flange off the pipe and
weld it to the new pipe
its stainless steel
so tig or mig it
 

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I don't know that using the 1 wire 16v o2 with the 20v will work since the 20v uses a 4 wire. They both use the same voltages 0-1v, but you would be missing the heated part of it that does run to the 20v computer. I would think using the 1 wire could cause an error code, but maybe not.

If you want to try it, wire the black 16v o2 wire to the black OX wire (I think its black) on the 20v o2 connector. If it seems to run right, and doesn't throw a code, and doesn't drop into limp mode, then maybe you have found a cheaper alternative to using a toyota 4 wire harness.

If you do this, let me know how it goes.
 

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Discussion Starter #4
well unfortunately i can't help solve the mystery, my 88 16v sensor is a 4-wire heated one. and, unfortunately, the 16v has two solid black wires among the 4. i have an 88 BGB, so i know what the 16v wires are. one for signal to the ecu, one for signal from the ecu to turn on and off the heater, one power, and one ground. but i don't know that the ones on the 20v are entirely. i know which is the heater signal, but then it shows two more of them going through the ecu?

oh, and i think you can use a 1 wire with a 4 wire setup. you just forego the benefits of a heated sensor. thats all. the ecu still gets its signal just fine. i think some mk2 guys do this when dropping turbo motors (4wire) into n/a cars (1wire).

and unfortunately i can't weld, so just putting another bung on isn't as easy as it sounds. (wish i could tho. buying a welder and learning how is right at the top of my list for things to do in the next few months.)
 

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Yeah, and the muffler shop would rip you a new one for this type of work.

Try matching up just the signal wires (ox to ox) and see if that works.
 

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Look at the bottom here for an explanation of all wire colors:

http://www.boschusa.com/images/OxygenSensorInstall.pdf

The 2 black ones you have are the heater wires. If the 16V one has a green wire then the signal wire is the white one. If it doesn't have a green wire then blue is the signal, and white is the ground.
 

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It will throw code w/out the heater connected. How much it affects the cars running, not positive, but I want to say my car wasn't too happy with me for it.

I believe the thing Eric posted is what I would have sent you. Post again if you still have problems and I can walk you through it.
 

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Discussion Starter #8
in fact i know the 16v side of it, i have a BGB. it has a white and a black, which are power and ground. and a blue/white with is actually the heater signal wire, and another black which is the ox signal wire (think thats written out right...).
however the 20v has a pink/blue for the heater signal, and also a black/red, a red/black, and a str8 black, whihc is the shielded wire for signal i think. but i'm confused why three of the above wire all go to the ecu? only two should i would have thought.
 

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Discussion Starter #10
read it, and that helps explain a bit..but i haven't yet been able to wrap my mind around it all. (i usually have to think through where all wires go and do until i have the whole layout in my head, then just wire it up, but its not goin quickly :p )
i sent sclay115 an e-mail
 

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Discussion Starter #12
i try to avoid that....

once, in a moment of brainlessness, hooked the battery up backwards in our roadster.
turned the car to ON, and burnt the sheath off the main ignition wire from the inside of the dash to the next conenction in the engine bay. fortunately thats all. gotta love old cars with little or no wiring. only took me about 5min to fix that little screw-up.
 

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Discussion Starter #14
so its got a power and ground like the 88 one, the ground just happens to go through the ecu. and its got a heater control wire form the ecu, and a OX sensor wire back to the ecu?
i can identify the three coming form the cu, so this should be more str8 forward. i'll give it a shot this weekend when i crawl under there to fix my oil leak on the filter adapter.
 
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