I think one of my O2 sensors is dead. The car started running shitty today at part throttle acceleration and cruising. Very boggy and it shakes. When I give it more gas, it takes off like a bat outta hell. I haven't gotten an SES light or any DTCs yet, already checked with Autotap. The B1S1 O2 sensor shows 1.105V all the time even when the car is off. I'm getting like -10% LTerm Fuel trims on that side. Sometimes at idle, I see a -30% to -43% next to the 1.105V on the B1S1 O2 sensor line. Is it safe to say that sensor is dead or could it be something else?

 

Swap the sensor with B2S1 and if the problem switches sides then its the O2, if the problem remains on the same side as before, then you have an issue!

 

TTT

Still need help with this. I bought 2 new GM sensors. Before I opened them up, I switched the B1 and B2 sensors. I saw the 1.105V go over to B2 so I figured it was the sensor. I plugged in the new ones and checked on Autotap. They both looked normal and didn't go to 1.105V right away.

Took the car out for a drive and it felt a lot better. Much better throttle response than before and WOT seemed better. I waited until it got above 180* to beat on it. About 10 minutes into the drive it started idling bad like before and Autotap showed 1.105V on B1 again. ****!! I brought it back and switched the sensors with each other. Once again, the 1.105V showed up on B2 after the switch. I switched them back, and see 1.105V on B1. What gives? I still have no DTCs and no SES light.

Does this full rich condition on B1 indicate a vacuum leak? Is something happening that smokes my O2 sensor right away? This wasn't a gradual thing. Happened all of a sudden on Thursday.

I have no misifires showing up. If it's not one thing it's another with this ******' car.

 

Yeah, it could be a leak letting clean air into the exhaust, causing the PCM to dump more fuel.

 

Well I think I found the problem. I pulled the valvecover and saw I'd broken the #3 exhaust spring. If that spring is hanging open at all, raw fuel would just go right on through and hit the O2 sensor. I just wonder how long it's actually been broken and I never noticed until it screwed up the O2 sensor. It's a 941 so it didn't let the valve drop and it's broken right at the top coil.

With a new spring and new O2 sensors I should be running better than ever. For future reference, what valvesprings are a good alternative to 941s? I want to use the same titanium retainers and the same locks as with the 941s. I'd really prefer a dual spring or at least a single spring with a damper like the 941s. So even if one does break, I haven't trashed a brand new short block.

 

Back up to the top. I replaced the valvespring tonight and took 'er for a drive. After a few minutes of idling, it started running funny again. No throttle response, shaky, and the B1 O2 is back at full rich. I shut it down and restarted it. The bad throttle response seemed to go away a little bit. I beat on it a LOT and it's never pulled this hard before. Seems like it's spinning the clutch or the tires at the top of every gear through 3rd. Sounds great too, not like it's breaking up or anything.

I logged some of the WOT runs to see what happens when I punch it. When just cruising I could see the B1 O2 was still reading full rich much of the time, with it switching lower every now and then. It did read normally for a little while but always seems to go back to 1.105.

What else could it be? Stuck injector? My injector pulse widths are in the mid to upper 3 range, sometimes going a little over 4. That's at idle. I noticed my MAP pressure seemed higher when the engine is idling badly. Normally it's 14.5-15 in/Hg. It got up to 17-18 in/Hg when it runs bad. Still no DTCs either. The MAF appears clean. I'm resetting the PCM right now. I have to go out later so I'll check things again. F*cking frustation!!

 

Resetting the PCM must've jogged something. Now I get P0132 High voltage on B1 O2 sensor. No **** sherlock!

EDIT: remember, this is a brand new O2 sensor.

 

Mods: Would this get more attention in another forum? I fixed the spring but still having problems. It runs a little better but still stumbles. I've noticed my O2 sensor now read 0.000mV a lot instead of full rich.

 

Check the ground for the O2 sensor on the back of the drivers side head. If loose or broken it will give you these types of issues.

 

Sounds like a sensor is off, making the car run phat.

 

I checked the grounds. It feels like there are three wires that are grounded at the back of the head. Sound right? There's also a ground strap running from the connector that the B1 O2 sensor plugs into up to the frame rail behind the radiator on the drivers side. Is this ground strap supposed to be exposed or should there be some of the corrugated tubing around it? What are the blue and light blue wires at the back of the intake? I just wanna make sure none of the insulation on the wires have been exposed.

I pulled the plugs. Every plug on B1 is all carboned up and dry. Every plug on the passenger side looks perfect.

 

The grounds sound correct. Are you having a spark problem on B1? have you tried swapping the O2s from side to side? Do you have O2 extensions for long tubes?

 

Ok, I just changed the plugs and the car runs great. Great throttle response and power. It doesn't chug like it had before. I think I had it out about 15 minutes. I may drive it tomorrow to see if it comes back with some traffic duty. I logged a WOT run from 2nd to 4th. My B1 O2 readings scare the **** out of me. But no KR at those low voltages?

O2 - B1S1 O2 - B2S1 LTFT - B1 LTFT - B2 Timing Adv RPM ECT Ign Volt TPS Knock Retard MAP MAF Rate
0.000 0.170 0.0 0.0 32.0 2400 187 13.7 Volts 1.7 0.0 21.6 8.77
0.650 0.735 0.8 0.0 32.0 2714 187 13.7 Volts 1.7 0.0 20.4 10.08
0.645 0.100 0.8 0.0 31.5 3054 185 13.6 Volts 3.4 0.0 28.3 18.57
0.520 0.855 7.8 8.6 28.0 3698 187 13.7 Volts 4.3 0.0 28.3 22.38
0.370 0.900 7.8 8.6 24.5 4309 187 13.6 Volts 4.3 0.0 28.1 29.13
0.300 0.895 7.8 8.6 23.5 4910 185 13.6 Volts 4.3 0.0 28.1 31.85
0.535 0.905 7.8 8.6 27.0 5489 185 13.6 Volts 4.3 0.0 27.5 36.24
0.495 0.915 7.8 7.8 37.5 5458 185 13.8 Volts 0.6 0.0 3.2 1.43
0.000 0.085 0.0 0.8 24.0 4386 185 13.6 Volts 4.3 0.0 28.3 28.68
0.535 0.890 7.8 8.6 23.0 4751 185 13.6 Volts 4.3 0.0 28.1 29.00
0.505 0.900 7.8 8.6 24.5 5048 185 13.6 Volts 4.3 0.0 27.8 30.38
0.485 0.910 7.8 8.6 26.5 5346 185 13.6 Volts 4.3 0.0 28.1 33.10
0.485 0.900 7.8 8.6 27.5 5625 185 13.6 Volts 4.3 0.0 27.2 30.94
0.510 0.810 5.5 5.5 38.0 5048 185 13.7 Volts 1.6 0.0 27.8 29.54
0.510 0.880 7.8 8.6 24.0 4586 185 13.7 Volts 4.3 0.0 28.3 29.51
0.520 0.885 7.8 8.6 23.0 4765 185 13.6 Volts 4.3 0.0 28.1 30.85
0.500 0.885 7.8 8.6 24.0 4954 185 13.7 Volts 4.3 0.0 28.1 30.85
0.480 0.880 7.8 8.6 25.0 5124 185 13.6 Volts 4.3 0.0 28.3 33.99
0.495 0.905 7.8 8.6 26.0 5302 185 13.5 Volts 4.3 0.0 27.8 34.75
0.480 0.900 7.8 8.6 27.0 5470 185 13.6 Volts 4.3 0.0 27.8 31.46
0.475 0.885 7.8 8.6 27.5 5612 185 13.6 Volts 4.3 0.0 28.1 33.10
0.470 0.885 7.8 8.6 27.5 5764 185 13.6 Volts 4.2 0.0 27.8 33.84
0.455 0.890 7.8 8.6 27.5 5894 187 13.6 Volts 0.6 0.0 3.5 1.35
0.085 0.065 2.3 2.3 38.0 4910 185 13.7 Volts 0.6 0.0 3.2 1.34
0.000 0.030 0.0 0.0 38.5 3841 185 13.7 Volts 0.6 0.0 4.1 1.18
0.000 0.030 0.0 0.0 39.5 2991 185 13.7 Volts 0.6 0.0 5.3 1.29

 

After driving the car for about 35-40 minutes today it started stumbling again. I can hear and feel it if I hold a gear anywhere from 1600-2500 rpm. I'm afraid to beat on the car given the low O2 readings from above. Have to check the plugs when the car cools down.

 

I really can't read those numbers they give me a headache, what is standing out?

Give me the highlights.

 

At WOT in 4th gear I'm seeing .470-.520mv on my B1 O2 sensor. But there's no knock retard and the engine doesn't rattle. Also, my LTFT on B1 are lower than B2. If I was running that lean on B1 wouldn't my LTFT be up around 25% trying to compensate?

EDIT: I just check plugs again. After driving 10 minutes to work and another 40 or so at lunch today, every B1 plug is all covered in black soot. B2 looks fine.

 

I finally got an SES. When I tell Autotap to look up the DTC, it floods the screen with different versions of the P1133 code and either reboots my laptop or shuts down Autotap. With the car running, B1 O2 and B1 LTFT are both stuck at 0.

 

The trace is too short and hard to read but the left 02 averages at 456 mVolts
where right 02 is 776 mVolts ( about 12.9:1 AFR).
Both banks fuel trims about 7% lean.

Being what the RPMs were and guessing the MAP was in lbs/min ?
if so and pushing about 32 lbs/min you were in PE mode thus that would say left head is not getting enough fuel or the PCM's bias voltage of 450 mVolts is what is being seen and something wrong with PCM wiring to that O2 or left head problem.

 

.475 or something like that, if it stays constant could indicate a bad 02.

But if you changed it, and it still does it, then maybe the 02 harness is burned or messed up. If this is the front o2 for the passenger side, it runs in a foilwrapped bundle down the fender by the #4 and #6 header primaries. If you burned thru one wire I'm sure the 02 won't function. In that bundle are the passenger front 02, starter (to the bcm), and crank wires.

 

Have you checked for header leaks? I had a major one in the back on cylinder 7 that you couldn't see unless you pulled the motor. This header leak caused me to go through four 02 sensors on bank 1.