#1: Dreaded Emissions Author: shaun88, Posted: Tue Oct 09, 2012 2:28 pm ---- hiya all,
i have an mot fail on,
exhaust emissions carbon monoxide content after 2nd fast idle
exhaust emissions lambda reading after 2nd fast idle outside specified limits.
now i have noticed it failed on the same thing last year and then passed previous owner says he fitted new cat and lambda sensor, now the main question i have is the new lambda sensor is a spliced unit i.e the cables are joined from original plug to new lambda sensor, are these any good and what would reccomendations be for cures as i am unsure about what second fast idle is.
one thing to point out is that at the time of testing the exhaust had come apart before the cat and was blowing at the joint could this affect the second fast idle????
thanks in advance guys..
#2: Re: Dreaded Emissions Author: pug206lx, Location: Taking a gearbox off somewherePosted: Tue Oct 09, 2012 5:44 pm ---- Yes if the exhaust is leaking gas before or near any of the sensors then it can affect the lambda sensor readings and this can lead to MOT failure.
The connection between the lambda sensor and the plug should be ok as long as the connections are in good condition.
#3: Re: Dreaded Emissions Author: shaun88, Posted: Wed Oct 10, 2012 9:03 am ---- That sounds good, just worried as the sensor is before the break in the system, do you still think it could affect emmisions or should i replace lambda and repair the joint on exhaust?
#4: Re: Dreaded Emissions Author: Gavin28, Location: BlackpoolPosted: Thu Oct 11, 2012 3:18 pm ---- I would fix the exhaust, and take it for an Italian tune-up (rag it!) just before the retest.
But that's just me.
#5: Re: Dreaded Emissions Author: mickpig1953, Posted: Sun Aug 11, 2013 6:04 am ---- can anyone help which lambda sensor does secund fast idle relate to, post cat or pre cat?
#6: Re: Dreaded Emissions Author: mickpig1953, Posted: Sun Aug 11, 2013 6:04 am ---- can anyone help which lambda sensor does second fast idle relate to, post cat or pre cat?
#7: Re: Dreaded Emissions Author: kandlbarrett, Location: SwindonPosted: Sun Aug 11, 2013 7:30 am ---- Both. The reading for the MOT is taken at the tail pipe. Any defective lambda or leak will cause a fail. Fix the exhaust leak first. Was the reading high or low. It should be on your fail certificate.
High reading (excess 02) is usually an exhaust leak post lambda and often post cat.
Low reading is usually leak pre lambda.
Get all of the readings from your fail certificate and we will have a better idea what we are looking for.
We are not responsible for comments posted by our users, as they are the property of the poster
Interactive software released under GNU GPL,
Code Credits,
Privacy Policy
Membership:
Latest: 
New Today: 0
New Yesterday: 1
Overall: 17127
Online Now [61]:
Visitors: 60
Members: 0
Staff Online Now:
Page Views:
General
