MOT Failure on Emissions
Discussion
I put my S1 Elise in for an MOT today and it failed on emissions. The garage have suggested the catalytic converter could be the problem. When I bought the car, there was no cat fitted so I bought one brand new. It has been on the car for about 10,000 miles.
This is the printout I received from the garage.
As you can see, there are no recorded readings. The story from the garage is the car began overheating so they had to abandon the test. The emissions tester did not record a reading but they observed a reading on the screen, which is written in biro. The first reading is the fast idle and the second is the natural idle.
They spotted fluid coming from the coolant expansion tank and it turns out there is a very small hairline crack down the front. When the coolant gets hot, it leaks very slightly. I drove home 5 miles in stop-start traffic, getting out to check now and again, and there was no sign of overheating.
The thing that looks fishy is the oil temperature shows as 18 degrees C, but the MOT manual says the test should be done with the engine warm. Could a cold engine cause the readings to be high?
This is the printout I received from the garage.
As you can see, there are no recorded readings. The story from the garage is the car began overheating so they had to abandon the test. The emissions tester did not record a reading but they observed a reading on the screen, which is written in biro. The first reading is the fast idle and the second is the natural idle.
They spotted fluid coming from the coolant expansion tank and it turns out there is a very small hairline crack down the front. When the coolant gets hot, it leaks very slightly. I drove home 5 miles in stop-start traffic, getting out to check now and again, and there was no sign of overheating.
The thing that looks fishy is the oil temperature shows as 18 degrees C, but the MOT manual says the test should be done with the engine warm. Could a cold engine cause the readings to be high?
I would be asking in strong language why the test was carried out with the oil temp at only 18 degrees. If they then say that they had to abandon the test due to overheating, surely this would have been found BEFORE connecting the car to the test equipment? I cannot believe that an MOT would be commenced before a vehicle's engine was up to NORMAL operating temp. Please correct me if I am wrong, as I did MOTs a very long time ago before all this emission crap came in. (sorry for that last remark, I know that the testing prevents some smoke-emitting horrors from being on the road)
Special K said:
I would get in touch with an Elise friendly MOT station. PM me if you need any help finding one locally 
Thanks for that. I would like to get to the bottom of the problem really - it breezed through its last MOT on the emissions test. I have made no changes to the engine, exhaust or induction since then so I would like to get it sorted. I will send you a PM shortly anyway for future reference. Someone on the Elise forum PM'ed me with a name - perhaps it's the same one! Ganglandboss said:
Thanks for that. I would like to get to the bottom of the problem really - it breezed through its last MOT on the emissions test. I have made no changes to the engine, exhaust or induction since then so I would like to get it sorted. I will send you a PM shortly anyway for future reference. Someone on the Elise forum PM'ed me with a name - perhaps it's the same one!
I pm'd you through here but not sure if that is what you're referring to ?StevelKinevil said:
Looks like the tester saw a potential problem and decided to cut it short in case there was costly damage or an exploding header tank.
Get it fixed and take it back. Should be a free retest within 10 days surely?
They are my thoughts but the bloke at the garage when I collected it was suggesting the cat was knackered. The part is ordered and will be on the car next Friday, ready for a retest next Saturday. I would understand if they said they abandoned the test because of the risk of damage but I'm confused why they did the emissions test at all if the engine wasn't warm.Get it fixed and take it back. Should be a free retest within 10 days surely?
Ganglandboss said:
StevelKinevil said:
Looks like the tester saw a potential problem and decided to cut it short in case there was costly damage or an exploding header tank.
Get it fixed and take it back. Should be a free retest within 10 days surely?
They are my thoughts but the bloke at the garage when I collected it was suggesting the cat was knackered. The part is ordered and will be on the car next Friday, ready for a retest next Saturday. I would understand if they said they abandoned the test because of the risk of damage but I'm confused why they did the emissions test at all if the engine wasn't warm.Get it fixed and take it back. Should be a free retest within 10 days surely?
AndrewW-G said:
I'd suggest fixing the tank, cancelling the cat and giving the car an Italian tune up on the way to next weeks retest. . . . . . . from your posts, the car failed as they were unable to test, no emissions figures = dont waste your money on a new cat until it has been fully tested and you know 100% that it does need a new one
At the risk of further confusion, Andrew, i think the part that is mentioned on order is the header tank and not the cat. That is the way i read it.cheers
StevelKinevil said:
AndrewW-G said:
I'd suggest fixing the tank, cancelling the cat and giving the car an Italian tune up on the way to next weeks retest. . . . . . . from your posts, the car failed as they were unable to test, no emissions figures = dont waste your money on a new cat until it has been fully tested and you know 100% that it does need a new one
At the risk of further confusion, Andrew, i think the part that is mentioned on order is the header tank and not the cat. That is the way i read it.cheers
t out of the car on the way to next weeks MOT to get it nice and warmed up 
If everything is fine then you shouldn't in theory need a catalyst anyway. My old (pre cat) Sierra passed with emissions levels lower than requite for catalyst cars. If that really was the oil temperature then something is wrong somewhere. It may be that they didn't even insert (ooer) the probes, and gor paranoid when it started to apparently overheat. The temperature you are seeing is air temperature.
Quite why they are telling you about emissions with no actual proof is another matter. Unless they cocked up and forgot to print it out, and just printed a random blank sheet later.
My dad's motor was in for MoT today, and while he was there one of the cars being tested broke a cam drive belt. Ouch.
Quite why they are telling you about emissions with no actual proof is another matter. Unless they cocked up and forgot to print it out, and just printed a random blank sheet later.
My dad's motor was in for MoT today, and while he was there one of the cars being tested broke a cam drive belt. Ouch.
It seems that it failed the Basic Emissions Test (BET), for which they noted the readings manually and didn't want to to do a cat test on it due to the coolant loss problem, so they pushed the buttons on the computer with the aim of producing the print out. Regarding the oil temperature on the sheet, it is required to be checked when doing the cat test, as they didn't do the cat test they didn't measure the oil temperature, so the reading recorded is the ambient air temperature in the test bay.
The BET would have been done first and the engine would have been warm, gauge showed correct coolant temperature, coolant pipes were hot or cooling fan kicked in, are the criteria for assessing engine temperature on the BET.
It seems a sensible course of action, the alternative is to abandon the test, charge for it and when the coolant loss problem is fixed, to test it and charge for a full test. Looks like they have saved you a test fee by doing it this way.
The BET would have been done first and the engine would have been warm, gauge showed correct coolant temperature, coolant pipes were hot or cooling fan kicked in, are the criteria for assessing engine temperature on the BET.
It seems a sensible course of action, the alternative is to abandon the test, charge for it and when the coolant loss problem is fixed, to test it and charge for a full test. Looks like they have saved you a test fee by doing it this way.
Edited by mcford on Friday 14th October 07:42
As already stated oil temp is not requred on the inital Bet test only if it fails this & requires a full test, i would not think an itailian tune up or replacement cat convertor would cure emissions that are that high as without a cat it should be much lower than that.
I would be looking for a faulty sensor possibly lambda or coolant temp sensor both can cause excessive co best to get a diagnostic computer plugged in & check the live reading assuming the engine light isnt on??
I would be looking for a faulty sensor possibly lambda or coolant temp sensor both can cause excessive co best to get a diagnostic computer plugged in & check the live reading assuming the engine light isnt on??
As above, to be fair to the station, if you are getting 2.5+ on the CO (I assume those figures are the % of CO?) there's no way you are going to pass anyway. For reference, my (non cat, non fuel injection) V8 Stag recorded 1.09% the other day. Your car should do much better then that, even without a cat.
If the cat is damaged I wouldn't be surprised if it's been poisoned by your engine running rich.
It's always a good idea to present your car to the MOT station hot and after a drive. That way it can be tested fairly.
If the cat is damaged I wouldn't be surprised if it's been poisoned by your engine running rich.
It's always a good idea to present your car to the MOT station hot and after a drive. That way it can be tested fairly.
AndrewW-G said:
StevelKinevil said:
AndrewW-G said:
I'd suggest fixing the tank, cancelling the cat and giving the car an Italian tune up on the way to next weeks retest. . . . . . . from your posts, the car failed as they were unable to test, no emissions figures = dont waste your money on a new cat until it has been fully tested and you know 100% that it does need a new one
At the risk of further confusion, Andrew, i think the part that is mentioned on order is the header tank and not the cat. That is the way i read it.cheers
t out of the car on the way to next weeks MOT to get it nice and warmed up One thing they said when I picked it up re. the lambda sensor. I asked if that could cause a high reading and he said it could, but generally the readings are erratic if that is the problem. On the printout, I gather the reading should be between 0.95 an 1.09 - what units are these?
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