View Full Version : MoT test question (emissions)
My VVTi has failed it's MoT test on emissions. The printout from the "Johnson Controls Ultima Gas analyser" shows the following :
Fast Idle Test : ...FAIL
Engine speed: ......NOT CHECKED
2350-2650rpm .......----rpm
CO: <0.30%vol
.....0.77%vol ......FAIL
HC: < 2000ppm vol
......45ppm.........PASS
λ : 0.970-1.0303
....0.998 ..........PASS
The car has had the front cat removed but still has the second cat fitted. I don't have the front cat, it snapped.
I've seen post on here where folks were saying these imported Supras shouldn't have a cat test but the MoT guys say it says on their computer that it does have to have a cat test. Are they correct?
At the moment I'm waiting for the car to cool down enough for me to take the Lamda sensor out for cleaning. What can I do to get it through the test?
Thanks
geoffvalenti
28-10-05, 11:20
Hi Jake
That's a bit of a bastard :(
Personally, I'd change the lamda sensor and try it again.
Make sure that the car is really hot before you stick it on the meter.
If that doesn't work, maybe try to borrow a 2nd cat from someone on here, there's got to be a few floating about :D
It should pass OK with just one (2nd) cat. Maybe yours is a bit weak, but as I say, stick a new lambda sensor on first, for £50-60 it's got to be worth a try ;)
Hi Geoff, thanks for that.
My other car passed the MoT last week with the same cat, so I don't think it's that. I reckon I'd have trouble finding a VVTi front cat to borrow 'cos they're different to the non-VVTi ones.
I may be wrong but lambda is spot on isnt it? So what is cleaning / changing the lambda sensor going to achieve?
The car was at operating temprature? I always make sure the car is hot before it goes in for an MOT.
Yeah, your lambda is fine, it's the CO levels that caused the failure, and I can't recall what causes carbon monoxide to go up or down... :help:
-Ian
Did you wam up the cat for a liong time?
Did you wam up the cat for a liong time?Well I didn't but the MoT tester said he had it so hot it melted his probe thing. :shrug:
Just out of interest Jake where did you take your cars for MOT? I used to use a garage in Southsea for my gf's old banger, but a bit of a back street operation and it's changed hands since... can you recommend your place..?
Do they know what their talking about with Supra's? not going to 'create a problem' to get some business....?
Hope you get the emissions sorted... don't know how you run two of these things! ;)
OK so if the Lamda is OK what else can I do?
Would a new air filter and spark plugs help maybe?
mine went through ok last week with just the front cat in, aftermarket system from that,
check your air filter, plugs and run good petrol
Just out of interest Jake where did you take your cars for MOT? I used to use a garage in Southsea for my gf's old banger, but a bit of a back street operation and it's changed hands since... can you recommend your place..? Hi mate,
I always take our cars to Sycamore Cars in Emsworth. (The first Texaco petrol station on the road from Havant to Emsworth) Their number is 01243 377755
Do they know what their talking about with Supra's? Nope! :p
I only use them for MoT tests. They're good for those because they don't get silly over things. They've never failed a car of ours for anything I didn't agree with.
Brilliant, cheers... I'll look them up... it's just a bit of a case of trail and (expensive) error finding a trustworthy garage when your not from round these parts... much appreciated.. :respekt:
Mine got through with no cats, but I dialed out the safc to -30% (>19 afr) while he was doing the test.
Mine got through with no cats, but I dialed out the safc to -30% (>19 afr) while he was doing the test.
Am I wasting everybody's time by saying what the hell does that mean? :looney:
Faye's Brother
28-10-05, 12:04
Jake,
Although it was on my Subaru, that CO figure is roughly what I saw when it failed its MOT on emissions grounds.
The car had a high flow sports cat in the centre section, but nothing in the downpipe. At the time of the MOT, it was suggested to me that the cat may not be performing to its full efficiency either through a manufacturing defect or simply because it wasn't getting hot enough being further away from the turbo than the downpipe cat would be.
Given that a Supra normally seems to pass on the centre cat alone, it may be that perhaps yours is not performing as it should in the light of that CO reading? However, having said that, I would have thought that a cat of that age would still be up to the job.
But he said the same cat worked fine on his other car last week if I'm reading what he put correctly :confused:
Its a bummer, my pug has a screw I can turn to adjust the idle co2 mixture, shame the supe dosn't have it!
But he said the same cat worked fine on his other car last week if I'm reading what he put correctly Spot on Neil mate
Faye's Brother
28-10-05, 12:17
Sorry about that. :)
Typed the reply after the initial post (so as not to forget to respond) and then saved it for posting during my 'legitimate' lunch break.
I still think its a heat issue.
My VVTI failed the first MOT as the result of a faulty Lambda sensor.
But the emissions were way out.
CO was 8.6 , HC 294 and Lambda 0.749 (very rich)
It passed the re-test with a new Lambda sensor.
The HC and Lamda values were very close to what you got.
For the CO value I got 0.073 compared to your 0.77.
I had both catalysts in place.
Looks like your Lambda sensor is working okay, if it's faulty it would make the mixture richer to prevent damage to the engine.
The catalysts will convert poisonous CO to less harmful C02 .
Right, I've cleaned the Lamda sensor, changed the air filter and fitted new plugs.
I'm going back down there now to see if they'll retest it for me.
Fingers crossed.
Nope. Failed again. Readings about the same or worse than before I changed the plugs, air filter and cleaned the Lamda sensor. I get the engine really hot before the test. Even tried resetting the ECU
I don't know what else to do now.
Doh! Good luck with it dude
geoffvalenti
28-10-05, 17:15
Jake, can you try the lambda/oxygen sensor from your other Supra, or is it different on the VVT-i?
The oxygen Sensor detects the relative amount of oxygen that remains after combustion in an engine. The oxygen sensor is electrically connected to the on-board computer, which interprets the signal and adjusts the air-fuel ratio as necessary. If it's faulty it can allow the engine to run rich with too high CO levels.
Sometimes, when testing, increasing the engine speed up to the maximum allowed, (for the test, not redline :D) about 3000rpm IIRC, can bring the CO levels down enough to get a Pass.
This depends on whether the tester is friendly enough to fcuk about in order to massage it through ;)
IME emissions test failures are nearly always oxygen sensor (prime candidate) or the CAT.
If the cat worked OK last week, the chances are it's still OK now.
Unless the car is running like a pig, it's unlikely to be ECU/injectors or the like.
Gutted for you over the wheel mate, it's just not your day :(
Jake, can you try the lambda/oxygen sensor from your other Supra, or is it different on the VVT-i?
:(
Different one on the VVTI, I checked the part numbers when I got mine.
Are they? Bugger.
If you've got the part number and price it would be handy.
cheers
Not cheap!
89465-19725 ..... £134.26 including VAT without any discount :(
It's a lot of money to pay out if it's not the oxygen sensor.
Whitesupraboy2
28-10-05, 20:25
i failed on this last MOT just like u Jake.....search for my MOT thread mate. I got away with cleaning my Lamba Sensor in petrol in end. Soaked it for 30mins!!!
But i think ill need a new one before next MOT. I am a NA not that will make any difference.
geoffvalenti
28-10-05, 20:30
Have a word with CW, I'm sure he sells pattern parts for half the Toyota price.
What about the place where you got your engine, they may still have the lambda sensor from Robs old car.
hi the limit for a cat test on a 1994/5 on car is 0.200 c.o so i am guessing that your print out should show this? not 0.30 as you have shown? there are some ways around the prob as the engine speed is not able to be tested so if you M.O.T tester is a normal bloke and not an asshole he can test the car on tickover, this can get the emissions down to a pass {sometimes} or he can run the car well over th 3k max to bring the temp right up to stabilise the second cat then all should be fine?
Timwildman
28-10-05, 20:45
My old car, now IVAN's passed with the front cat out, and he had the front cat off me when he took the car. It might be worth a pm to see if he still has it?
Jake, it wont solve the fault but it might be worth be worth another 30 odd quid to try another garage.
Jake, it wont solve the fault but it might be worth be worth another 30 odd quid to try another garage.
30 quid for an MOT, tell all, where do you go???
Jake i happen to know a friendly MOT tester!
30 quid for an MOT, tell all, where do you go???
Jake i happen to know a friendly MOT tester!
£38 Last time, its grim up north
hi the limit for a cat test on a 1994/5 on car is 0.200 c.o so i am guessing that your print out should show this? not 0.30 as you have shown? there are some ways around the prob as the engine speed is not able to be tested so if you M.O.T tester is a normal bloke and not an asshole he can test the car on tickover, this can get the emissions down to a pass {sometimes} or he can run the car well over th 3k max to bring the temp right up to stabilise the second cat then all should be fine? Thanks Sly but this car is a '98 VVTi. My printout definetly says 0.30.
He told me to hold the car at about 3000rpm for the test.
We did hold the car at 3000rpm for a couple of mins immediately before the test to get the cat good and hot but it still didn't pass.
Jake, it wont solve the fault but it might be worth be worth another 30 odd quid to try another garage.Aye, worth a shot I suppose mate
Cheers
Jake i happen to know a friendly MOT tester!
That's a coincidence! I was just thinking about you today mate. It was on my way home from my second failed MoT as it happens.
Odd that. :D
Jake,
My offer definitely falls into the category of less than ideal as I'm a little way from you but in case you don't sort this out another way the offer's there anyway...
Am planning to decat in the near future but could speed things up a bit and book in at Phoneix, Watford (if they're free) week after next as working in Watford for a couple days that week. If you cannot solve your problem another way my car would be there all day and you could nip up there, borrow the 1st cat and get your MOT done there.
Nick
Cheers Nick, borrowing a VVTi front cat would surely solve my problem. If I can't get it sorted out more easily I'll give you a shout mate.
Thanks a lot
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