Is this a bad WB02 on a Classic FAST?

[RonRed89]

All,

Still working to diagnose some no-start issues with my car. After more diagnosis, we've gotten down to the fact that there may be some IAC issues, but more importantly, it appears that the WB02 is heading south.

Here's a note from my mechanic showing our latest logs.
-----
I grabbed a data log this morning. The IAC motor & O2 sensor are looking like problems.

Today, the taget IAC was relatively high at start (90), car starts, idles for a little bit, then the IAC counts stabilize (60's to 80's) then they go
nuts and the car stalls.

Right before it stalls, the IAC count is at 180 (stuck IAC motor ??? or software glitch ?? not sure)

We also have an O2 sensor sitting at 3 volts the entire time, so in this test, if it's a heated O2 sensor, it's not sweeping.

Well, at least as far as this software is seeing it.

It's at 5 volts on start-up, then it flat-lines at 2.80 to 3.02 volts. Nothing is showing up in the Actual or Target A/F ratio's either......when the motor
dies, it goes back to 5 volts.

rpm iac

0 90
200 57
850 57
1100 57
450 57
650 50
700 35
1000 44
900 73 (IAC correction coming on-line)
700 91
1000 84
900 88
750 100
900 101
950 108
950 110
1000 111
850 112
950 118
900 132
1000 133
1000 125
1050 128
950 137 (IAC CORECTED)
1000 125-180 With no IAC Correction
800 180
450 180
500 180
550 180
500 174
350 180
800 159
------
Does anyone know the proper operation of the O2 sensor voltage wise? Does the above seem to indicate that this WB02 needs to be replaced?
Thanks for any tips.
Rony

 

[norbs]

This is not your normal o2 sensor your looking at the voltage the wrong way, and your IAC appears to just fine. You need to check the following voltages and make sure they are NOT and of the conditions below.


WBO2 not connected (UEGOR > 4.90V)-
WBO2 Shorted (UEGOR < 0.098V)
WBO2 not lit off (UEGOS > .07056V)
WBO2 malfunction (UEGOS < 0.196V)

Email me a datalog and your file,

I'll know right away whats going on.

norbz@sympatico.ca

 

[RonRed89]

Norbs,

Thanks a lot for your offer to help. The laptop and that data log is at the shop and I'll get you a copy of the GCT and log file as soon as I can. Thanks a bunch!

 

[norbs]

I would say your wideband is mis-wired as the voltage across the sensor is 0, which means its shorted, but it would be a rare case to have the resistor shorted, Check your harness. I have never seen a target af of zero either

 

[RonRed89]

Norbs,

Is this resistor something that I can replace on the sensor itself? From a wiring perspective, unless there is a short in this sensor back to the ECU, there shouldn't be anything mis-wired since this car has been running fine for several years. The tune was done as far back as 2007. Any suggested tests that I could perform? Thanks for the advice!

Rony

 

[norbs]

The resistor you can pull out of the WB sensor connector, but If you have another 02 try it, otherwise I would say the ecu is having internal problems.