MOT failure CO
Discussion
My runabout Rav4 (96) failed its MOT today on CO at idle /after 2nd fast idle.
Kept well serviced, had plugs and a new cat 3000 miles ago.
Just filled it up with Shell Vmax and a drop of Millers and given it an Italian tune up (wish I'd done it before MOT). Any other possible culprits?
Kept well serviced, had plugs and a new cat 3000 miles ago.
Just filled it up with Shell Vmax and a drop of Millers and given it an Italian tune up (wish I'd done it before MOT). Any other possible culprits?
dfen5 said:
My runabout Rav4 (96) failed its MOT today on CO at idle /after 2nd fast idle.
Kept well serviced, had plugs and a new cat 3000 miles ago.
Just filled it up with Shell Vmax and a drop of Millers and given it an Italian tune up (wish I'd done it before MOT). Any other possible culprits?
Given the vagueness of the description, a vague answerKept well serviced, had plugs and a new cat 3000 miles ago.
Just filled it up with Shell Vmax and a drop of Millers and given it an Italian tune up (wish I'd done it before MOT). Any other possible culprits?
The culprit could be a fault somewhere.
So in order to get a better response. What exactly were the emissions that led to a fail ? otherwise an attempt at diagnosis is impossible.
stevieturbo said:
Given the vagueness of the description, a vague answer
The culprit could be a fault somewhere.
So in order to get a better response. What exactly were the emissions that led to a fail ? otherwise an attempt at diagnosis is impossible.
CO - carbon monoxide, 0.352%. HC and Lambda ok. The culprit could be a fault somewhere.
So in order to get a better response. What exactly were the emissions that led to a fail ? otherwise an attempt at diagnosis is impossible.
dfen5 said:
CO - carbon monoxide, 0.352%. HC and Lambda ok.
Such a borderline fail really.It could be a cat temperature issue, or the cat itself. A lot of aftermarket cats just never perform as well as an OEM cat does, and certainly never for as long.
A good blast before having it tested might make the difference needed to make sure the cat is nice and warm.
stevieturbo said:
Such a borderline fail really.
It could be a cat temperature issue, or the cat itself. A lot of aftermarket cats just never perform as well as an OEM cat does, and certainly never for as long.
A good blast before having it tested might make the difference needed to make sure the cat is nice and warm.
^This you could reach those limits you posted without a cat on one of these engines all things being as they should, I would get that pattern cat checked out personally It could be a cat temperature issue, or the cat itself. A lot of aftermarket cats just never perform as well as an OEM cat does, and certainly never for as long.
A good blast before having it tested might make the difference needed to make sure the cat is nice and warm.
pattern cats I dislike 
short lived and poor quality IMO'fraid it is as they say, sounds like a s**t cat.
Can depend on how hard the garage try to warm it up, if they don't give a s**t they'll just leave it sit for an hour or two, let it idle for a couple minutes then test it. It can take a long time to get a car properly properly warmed up without moving it, believe me I've been sat in a car blipping the throttle watching the oil temp climb and it can take 30 mins to get oil up to temp, no garage is going to put that effort in.
You can always try arranging to get the emissions test done the minute you drive in to the garage and give it a good long, hard drive first. No guarantees but it'll give you the best chance of getting the cat saturated with heat.
Can depend on how hard the garage try to warm it up, if they don't give a s**t they'll just leave it sit for an hour or two, let it idle for a couple minutes then test it. It can take a long time to get a car properly properly warmed up without moving it, believe me I've been sat in a car blipping the throttle watching the oil temp climb and it can take 30 mins to get oil up to temp, no garage is going to put that effort in.
You can always try arranging to get the emissions test done the minute you drive in to the garage and give it a good long, hard drive first. No guarantees but it'll give you the best chance of getting the cat saturated with heat.
Bit of an update - I was looking at last year's figures.
This year, FI test (0.3) 0.549 fail, 2nd FI (0.3) 0.530 fail, Idle (0.50) 0.356 Pass.
Garage said new cat I'd had fitted at another garage was rubbish and to take it back.
I fitted a new Denso O2 sensor and cleaned out the throttle body (carefully), checked the IAC was operating & coolant temp' sensor. Took it back, had another cat fitted (looks a different make).
Had it checked, FI 0.58 (on a different machine, another garage). Guy's advice was thrape it for a good run to get the cat "glowing" then bring it in and it'll probably scrape through
Pulled plugs that were new 3k ago, all lovely tan colour, practically no soot. HC ppm (200) 18. Lambda (1.030) 1.020 Pass.
Back to the garage tomorrow. See what happens, still think the new pattern cat's useless.
This year, FI test (0.3) 0.549 fail, 2nd FI (0.3) 0.530 fail, Idle (0.50) 0.356 Pass.
Garage said new cat I'd had fitted at another garage was rubbish and to take it back.
I fitted a new Denso O2 sensor and cleaned out the throttle body (carefully), checked the IAC was operating & coolant temp' sensor. Took it back, had another cat fitted (looks a different make).
Had it checked, FI 0.58 (on a different machine, another garage). Guy's advice was thrape it for a good run to get the cat "glowing" then bring it in and it'll probably scrape through
Pulled plugs that were new 3k ago, all lovely tan colour, practically no soot. HC ppm (200) 18. Lambda (1.030) 1.020 Pass.
Back to the garage tomorrow. See what happens, still think the new pattern cat's useless.
dfen5 said:
Bit of an update - I was looking at last year's figures.
This year, FI test (0.3) 0.549 fail, 2nd FI (0.3) 0.530 fail, Idle (0.50) 0.356 Pass.
Garage said new cat I'd had fitted at another garage was rubbish and to take it back.
I fitted a new Denso O2 sensor and cleaned out the throttle body (carefully), checked the IAC was operating & coolant temp' sensor. Took it back, had another cat fitted (looks a different make).
Had it checked, FI 0.58 (on a different machine, another garage). Guy's advice was thrape it for a good run to get the cat "glowing" then bring it in and it'll probably scrape through
Pulled plugs that were new 3k ago, all lovely tan colour, practically no soot. HC ppm (200) 18. Lambda (1.030) 1.020 Pass.
Back to the garage tomorrow. See what happens, still think the new pattern cat's useless.
Again, quoting only partial results is pointless. All results go hand in hand with each other.This year, FI test (0.3) 0.549 fail, 2nd FI (0.3) 0.530 fail, Idle (0.50) 0.356 Pass.
Garage said new cat I'd had fitted at another garage was rubbish and to take it back.
I fitted a new Denso O2 sensor and cleaned out the throttle body (carefully), checked the IAC was operating & coolant temp' sensor. Took it back, had another cat fitted (looks a different make).
Had it checked, FI 0.58 (on a different machine, another garage). Guy's advice was thrape it for a good run to get the cat "glowing" then bring it in and it'll probably scrape through
Pulled plugs that were new 3k ago, all lovely tan colour, practically no soot. HC ppm (200) 18. Lambda (1.030) 1.020 Pass.
Back to the garage tomorrow. See what happens, still think the new pattern cat's useless.
Your statement after pulling the plugs, under what conditions are those and what CO at that same time ?
You mention looking at least years figures, but didnt actually mention what they were ?
And plugs should be pretty spotless, especially at idle and stioch running.
dfen5 said:
Had to laugh at the re-test figures -> CO 0.039 fast idle and 0.001 idle. Think, judging by the fuel that was gone, it was warm enough this time.
Still, passed so all done.
Amazing the difference a warm up can make Still, passed so all done.
You know for next time now, spank it on the way to the test centre and make them do emissions right away.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff