Hey guys, prior to my manual swap my S/C'ed 97 Limited ran great with the auto (both driveability and power wise) with a pro tune with the following power mods -

- 7th injector
- 2.2" pulley
- Walbro 190lph
- OEM Supra MAF
- URD MAF calibrator
- URD Injector/Timing calibrator

The 5 speed swap went in and it shifts great, but the AFR's are rich at idle and cruise (12-12.5) especially once WARMED UP.

I triple checked the wiring ('97 auto harness repinned for a '97 manual ecu) and did all the maintenance the forums suggested (cleaned MAF, IAC, TB, new plug wires, new o2 sensors, smoke test to check vacuum leak, checked the grounds etc etc) but the same problem persists. The CELs are p0135 and p0141 and here's what I've checked since -

- heater 1 wire = pin 3, pink/blue wire
- heater 2 wire = pin 9, red/white wire
- heater side gets 12v from white/blue wire from EFI
- both sensors see 0.9v on cold start
- ECU Voltage output is 3.3v for both heaters

You can see the lt/st fuel trims and oxygen sensor output voltage here -
YouTube

Any help is appreciated

OOOOO...I'm interested in this.

I have no help, as I'm going through the same thing now on my 96. I'm getting the P0141 even after replacing the sensor and verifying it gets hot when I run dedicated power and ground wires to it.

I've done some troubleshooting, and with key on and ECM connector unplugged I saw 4.2 volts at HT1 and HT2 coming right out of the ECM, which is different than your 3.3 volts.

I've taken both of my O2 sensors out of the exhaust pipe (but left them plugged in), turned the key on, waited a few minutes, but neither sensor heated up, but I'm only getting the rear code (P0141). This was done on a cold engine after sitting a few days so I was thinking they should heat up.

I've verified that I get 12V at the sensor with key on.

Maybe someone else may know something.

Hope someone can chime in and lead both of us in the right direction.

I don’t know. When I did my 5speed swap. I repinned my auto harness to accept a manual ecu. So I had 0 codes.

Maybe @TheDurk can help you

@onemanarmy my truck is fixed! Turns out there was a bit of corrosion in one of the plugs in the 5spd ECU i got from the junkyard. It's been 3 days with no codes and drives 100x better than before. Hope you get your truck sorted out too.

good news.

I'm still troubleshooting mine. I have yet to get confirmation on proper operation of the sensors.

Are they supposed to begin heating up with just the key 'on'? I took my sensors out and turned the key on (engine not running) and neither got warm.

Thanks

I didn't get a chance to see if they heat up with the key on, but can confirm they get power which you already know, sorry.