Code 91, O2's again??? WTF???

Hozer 88GTConv · 12-08-2006, 12:07 PM

Update:
As I'm driving around today between work sites, the car is running fine. Perfect idle, good acceleration, etc. The 02's register voltage right away after startup. Typically, .02 -.06 volts within a few seconds and then they begin switching high to low (like .72, .68 back to .22, .34 etc)...
but what happens is out of the blue, while at a stoplight or something similar the 02's stop sending voltage. Or at least it shows up on my PMS as .00 on both 02's.
The car immediately runs like crap, the timing goes all over the place, the rpms drop to 630-ish at idle and it will backfire through the exhaust.
I've noticed the tachometer jitters erratically when this happens. So I'm leaning towards an electrical prob, not an exhaust leak.
Thanks for your input...

Hozer 88GTConv · 12-08-2006, 06:02 PM

Update:
I added some fuel on the PT table with my PMS and the 02's seem to be working better than ever.
By that I mean that around idle to 3k the voltages are hovering right around .46 vdc which is ideal.
It still looks to be lean up higher.
I'll finish installing the wideband tomorrow. That should tell the real story.

12-08-2006, 12:07 PM	#1
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	Re: Code 91, O2's again??? WTF??? Update: As I'm driving around today between work sites, the car is running fine. Perfect idle, good acceleration, etc. The 02's register voltage right away after startup. Typically, .02 -.06 volts within a few seconds and then they begin switching high to low (like .72, .68 back to .22, .34 etc)... but what happens is out of the blue, while at a stoplight or something similar the 02's stop sending voltage. Or at least it shows up on my PMS as .00 on both 02's. The car immediately runs like crap, the timing goes all over the place, the rpms drop to 630-ish at idle and it will backfire through the exhaust. I've noticed the tachometer jitters erratically when this happens. So I'm leaning towards an electrical prob, not an exhaust leak. Thanks for your input... __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

12-08-2006, 06:02 PM	#2
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	Re: Code 91, O2's again??? WTF??? Update: I added some fuel on the PT table with my PMS and the 02's seem to be working better than ever. By that I mean that around idle to 3k the voltages are hovering right around .46 vdc which is ideal. It still looks to be lean up higher. I'll finish installing the wideband tomorrow. That should tell the real story. __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Code 81?? Code 51. HELP!!	blk88lx	Windsor Power	0	03-31-2004 08:22 PM
1972 Mach 1 "H" code but a 351CJ under hood?	757Driver	Classic Mustangs	1	09-16-2003 08:16 AM
code 15	tomazzzo	Windsor Power	1	06-06-2003 11:15 PM
Code 85...see if anyone can interpret	silver_pilate	Windsor Power	1	12-31-2001 06:24 PM
Code 81????	Chevyguy	Windsor Power	0	04-27-2001 10:44 AM