High CO emissions! Why!?
Thread Starter
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
High CO emissions! Why!? Ok, stock engine with free flow intake, 4 into 1 long tubes and 100 cell cats.
Lambda (AFR) Is 1.027 So slightly lean of stoich.
At idle and fast idle, 3000rpm I exceed CO emissions (Well not me, a friend)
He still runs closed loop. O2 sensors have previously had errors and were located post cat. Now running pre cat. No recent errors.
Im thinking o2 switching is slow due to futher back location and they get cold. Means engine runs rich and switches to lean slowly, when rich CO gets dumped triggering emissions failure.
The rules say stoich and leaner = no CO. Im going to try open loop and see if that helps.
But Id like to hear from anyone who has any more ideas on why its got so much CO. It exceeds 300ppm (the limit) HC is low and lambda is on the lean side of stoich so it doesnt make much sence.
Ive also raised idle speed and engine temp (raise fan temps) seemed to not make any difference.
HELP!
Lambda (AFR) Is 1.027 So slightly lean of stoich.
At idle and fast idle, 3000rpm I exceed CO emissions (Well not me, a friend)
He still runs closed loop. O2 sensors have previously had errors and were located post cat. Now running pre cat. No recent errors.
Im thinking o2 switching is slow due to futher back location and they get cold. Means engine runs rich and switches to lean slowly, when rich CO gets dumped triggering emissions failure.
The rules say stoich and leaner = no CO. Im going to try open loop and see if that helps.
But Id like to hear from anyone who has any more ideas on why its got so much CO. It exceeds 300ppm (the limit) HC is low and lambda is on the lean side of stoich so it doesnt make much sence.
Ive also raised idle speed and engine temp (raise fan temps) seemed to not make any difference.
HELP!
