I'm new bare with me please... Big fan of yota tech I research all the time for different problems I have with my truck!! Okay so I recently changed the clutch on my pickup and when I was dropping the tranny (by myself) I ended up snagging the o2 sensor wiring! After I got the clutch installed and the tranny back in I assessed the damage to the o2 wiring and I found one broken wire to I crimped it back together and started the truck, now I have a CEL and it reads code 21 which is o2 sensor fault/sort... Ect.... So I just ended up throwing a new o2 sensor in and that didn't change anything, I have done tons of research and can't find anything, Is it possible to rewire the four sensor wires all the way back to the ecm? I traced all the wires into the engine compartment and I didn't find any broken wires, but I think the wires stretched and broke internally when they got snagged? Also does anyone know the exact location the wires plug into at the ecm?
Any fixes/suggestions greatly appreciated!!

 

All I've got is the 88 ECU wiring diagram. It probably has a similar pinout to, if not the same as, 89. But it might not. Worth a shot at least.

 

thanks MudHippy I'm going to do some digging tomorrow and see if I can find anything.

 

Does anyone know what the resistances would be? I could probably find out if the wires are good or not like that.

 

And one more thing I have the dreaded idle surge when I start the truck up my idles at about 1200 RPM and then once the truck warms up if I step on the break the idle will jump up-and-down from 1000 to 2000 RPM does anyone think that could be caused by an O2 sensor I've checked for vacuum leaks with no luck. I also replaced the tps, and I have burped the coolant so there is no air in the system, could that be o2 sensor related?

 

Make sure the warm idle is set at 800 ± 50 rpm.

I'll see what I can do about the resistances.

BTW, from what I can decipher from the 90 3VZ-E wiring diagram I forgot I had, the pinout is different than 88. Which makes sense...since almost everything electrical is wired different for 88. Same number of pins on the ECU though. Anyway, can't be too much different than 89 I wouldn't imagine. Since everything electrical is identical.

I'll try and find the thread where I downloaded that. Or post up some pics.

 

Thank you much! I will be checking that tomorrow!

 

Here's that thread. https://www.yotatech.com/forums/f116...agrams-291305/

 

Awesome! And I checked the idle screw this morning and it was all the way turned in and my idle gets worse if I turn it out, I even saw on another post putting Teflon tape on the treads would help, but that made no change either, is there another way to adjust the warm idle?

One more thing, I was messing with the ac idle up valve (ac is currently not working) and I removed the hoses from the valve and the idle went down, but the ac wasn't even on, could that valve be my problem?

 

The idle speed adjustment screw should have an o-ring on it. If it doesn't, or it's dried up and needs replaced, that's probably the cause of your high idle problem.

I'm not sure about ac idle up. Maybe. I've never messed with one.

 

Okay I'll look it to that, thank you

 

Found the reason for my high idle and idle surge, turned out it was the clogged coolant hose that goes into the front of the throttle body. Couldn't believe the fix was something so simple!