Grand Prix Question

[SSpdDmon]

Any chance the scanner will work on a 99 Grand Prix? I know the tuning support isn't there. Is logging an OBDII car any different from model to model?

[joecar]

Jeff,

The scantool will be able to read the DTC's and all the OBD-II info; bidirectional mode may also work.

For logging pids, you may have to change Edit->Properties->Logging->Scan Mode (Stream Fast/Slow, Dynamic, Generic).

[SSpdDmon]

Cool - thanks Joe! I'll give it a shot. :)

[joecar]

Oh, if you do try bidi mode, do it with key on engine off... some of the commands may be interpreted differently.

[SSpdDmon]

Just did a simple log and it seemed to do some of the standard pids just fine. Didn't have to change anything.

The symptom reported was it felt like the converter was unlocking at abnormal times (while cruising along with traffic). But, we couldn't get it to do it again in the log. TC duty cycle appeared normal at 50%. I suggested replacing the O2 sensors and cleaning the MAF based on the knock sensor and fuel trim feedback. Plugs, wires and fuel filter recently changed. Car is a bone stock '02 Grand Prix GT (no blower).

[joecar]

Jeff,

That looks good...

I agree, clean MAF and replace air filter...

O2 sensor voltage is switching but seems to be shifted down a little...
first may want to check for air leaks before/after engine,
but may need to replace O2S anyway if it has 70K+ miles on it.

Also check that PCV valve is free (rattles ok)...
if it's oily, then it's sucking oil and that could induce knock.

Could also see if it logs TCCMODE (this says explicitly when lock is commanded).

The GP only has 1 cat, so HO2S21 and LONGFT2 can be ignored.

I'm impressed it logged CYLAIR_DMA... :cheers:

Cheers,
Joe
:cheers: