TurboKH

91 22RE, I recently replaced all the bulbs in the dash and founf there's a CEL on.. the truck didn't run "bad" before, but I checked the code and found it to be pointing to a bad O2 sensor. It does idle a little off (not usually an O2 sensor problem) and occasionally, lately, it would crank a little longer than usual before firing, so I figured what the hell.. put in a new sensor..

After installing the new sensor, it won't start at all. I rechecked the plug, put a little electrical cleaner on it, and reconnected. Still, no start. I put the old sensor back on and still nothing.

Any ideas? I'm pulling the wiring all the way back to the ECU to start OHMing out the stuff and try to find a bad one... Help?

-Karl

Elton

wich kind of sensor did you get also check the efi fuse

TurboKH

Bosch OEM, pre-wired plug so there was no guessing. Already checked the 15a. fuse for EFI when I pulled it to reset the CEL. Thanks....

Elton

umm is it to late to take it back ?

YotaFun

why do you say that?
My Bosch OEM replacement works perfectly, maybe even better....
It's all connectled right?
Did you unplug anything else liek the AFM or anything like that...
When I went to clean my MAF i forgot to plug it back so the Runner would turn over then die....
Just givin my .02....

TurboKH

I put the old one back in and it still doesn't start (it ran "okay" with the old one before I boiught the new one, other than the slight miss and the CEL). I've got the wiring harness pulled from the sensor to where it goes up the intake side of the engine. I figure I'll test all 4 wires from the sensor as far as I can go, eventually to their ECU connections. This is really weird. I had a different 91 a few years ago that had burned wires to the sensor, and that caused the ECU to fail.. I hope that's not the case this time.

Any more ideas... let me know! Thanks!

mt_goat

I doubt your O2 sensor is the reason for it not starting. I drove my truck to the exhaust shop with no O2 sensors connected at all and it ran fine.

TurboKH

Apparently, mine had to be connected. I found a bad wire in the truck-side of the harness right at the plug, so I replaced the plug and all 4 wires from the union near the engine down to the sensor. It's starting and running fine now. No more missing at idle. Thanks for your suggestions...

Elton

good to hear

mt_goat

That's good. Maybe a bad wire is worse than no wires?

TurboKH

Could be.. I didn't take the time to figure out what that wire's function was. Just happy to find the cause and get it going again.