O2 sensor readings with engine not running?
Thread Starter
Teching In
Joined: Apr 2006
Posts: 31
Likes: 0
O2 sensor readings with engine not running? I have been having the random cyl misfire code showing on and off the past week. Alot of rough idle and hesitation. So I changed the plugs from the tr6's to tr7ix iridiums(getting ready for nitrous) and it was the same.
So i changed the plug wires to see if it would fix it. Still the same.
I did some searching on here about misfire and came up with the o2 sensor readings, and the problems with mass/maf sensors, vaccum leak/pcv.
And the codes its is throwing is
p0137 o2 circuit bank 1 sensor 2 low voltage
p0300 random multiple cyl misfire detected
So i plugged in my diablo to see what it was showing on voltage on the O2 sensors and this is what i came up with.
Switch on/engine not running
Bank1 Sensor 1- 45mvolts < ?
Bank1 sensor 2- 785 mvolts
Bank 2 sensor 1- 820 mvolts
Bank 2 sensor 2- 935mvolts
Running at idle the voltage jumps around alot but mostly is running at 600-900 mvolts. But jumps down as low as 40-100 and then jumps back up to 600 +
From 20%-100% throttle positition is stays 700+mvolts consistantly. Most of the time at that full throttle it runs high 800 mvolts
Any ideas on where to start on this problem? Without breaking the bank trying to fix it.
Car is a 2002 Z28 A4, engine is stock with k&n fipk, descreened mass/maf and diablo predator. All other mods are driveline related.
Any help is appreciated thanks, Billy
So i changed the plug wires to see if it would fix it. Still the same.
I did some searching on here about misfire and came up with the o2 sensor readings, and the problems with mass/maf sensors, vaccum leak/pcv.
And the codes its is throwing is
p0137 o2 circuit bank 1 sensor 2 low voltage
p0300 random multiple cyl misfire detected
So i plugged in my diablo to see what it was showing on voltage on the O2 sensors and this is what i came up with.
Switch on/engine not running
Bank1 Sensor 1- 45mvolts < ?
Bank1 sensor 2- 785 mvolts
Bank 2 sensor 1- 820 mvolts
Bank 2 sensor 2- 935mvolts
Running at idle the voltage jumps around alot but mostly is running at 600-900 mvolts. But jumps down as low as 40-100 and then jumps back up to 600 +
From 20%-100% throttle positition is stays 700+mvolts consistantly. Most of the time at that full throttle it runs high 800 mvolts
Any ideas on where to start on this problem? Without breaking the bank trying to fix it.
Car is a 2002 Z28 A4, engine is stock with k&n fipk, descreened mass/maf and diablo predator. All other mods are driveline related.
Any help is appreciated thanks, Billy
Thread Starter
Teching In
Joined: Apr 2006
Posts: 31
Likes: 0
Thanks for the help. Ill check it cold this morning to see if idles smooth at first before the open/closed loop takes effect.
I have double checked the coil/plug connections over and over again and all looks good.
As for the grounds what ground locations would I check? The only ground connection I can think of is the one on the pass side front block/intake area near the throttle linkage, and the two fender well grounds, are there more?
The only ground that matters for spark would be the block grounds correct ?
Thanks for any help in this matter, Billy
I have double checked the coil/plug connections over and over again and all looks good.
As for the grounds what ground locations would I check? The only ground connection I can think of is the one on the pass side front block/intake area near the throttle linkage, and the two fender well grounds, are there more?
The only ground that matters for spark would be the block grounds correct ?
Thanks for any help in this matter, Billy
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
Not sure on Camaro as I have a Holden. But yeah, I think I recall some dude saying a little ground near the rear of the block was bust at one stage causing him issues. Maybe some other Camaro owner can confirm what grounds to check.
