14 replies to this topic

[neon1991]

had a strange one at the weekend.  I took the mini ive been rebuilding,  in for it's MOT.  it's had all sorts done.  pretty much every panel.  and a complete renew of the suspension,  new rear subframe,  inner and outer sills,  the lot.

 

The car failed on 2 items.  the first being a rough rear wheel bearing (annoyed with myself as the rear bearings are the only part of the running gear not to have been replaced! lol)

the 2nd item was emissions.  It's a 91 on a carb. no smoke on startup or when reved. used a colourtune to set the mix and it's an even light blue on tickover on all cylinders.

The tester said that the CO was "off the scale"  I asked him if he had a printout of the test result and he said no,  it was an immediate fail.  then he said that it could be the cat. 

 

the last comment got me as it doesn't have a cat.  I asked him what the reading was on the CO and he said "the machine didn't give me one and just said it was off the scale"

 

Ive just bought a gunson's gas tester and this gave a reading of 2.8% can anyone confirm what the limit is for 1991 998cc mini is?  I thought it was 3.5% which leaves me stumped in terms of why it failed their test....   if anything it could be a bit lean

[nicklouse]

i would challenge the emissions fail. after you have done the rear bearing.

 

yes 3.5% 

[unburntfuelinthemorning]

Yes 3.5% CO maximum at idle for MOT.  Specifications for a 1991 998cc Mini state 1.5 to 3.5% CO at idle.

 

It's a bit odd that he blamed the cat as he'd just tested the vehicle so should have seen that there isn't one!  Also if it was off the scale rich the exhaust fumes would have smelt terrible.

 

Maybe find another garage to test the emissions only for a small fee?

[neon1991]

Cheers guys,  that's what I thought.  very odd to mention the cat.  the car doesnt stink at all.  my old vw pickup properly hums but thats never had a problem although MOT exempt now

 

they have agreed to do a retest for free despite them not getting the work for the bearings... (they had a week wait list - no wonder with the fail happy chap on the test station).

I think he might have just put it in for a cat test and after failing,  couldn't be bothered with the basic one.

[unburntfuelinthemorning]

They enter your vehicle details into the almighty computer now before the test - that should have told him which test to perform.

[neon1991]

They enter your vehicle details into the almighty computer now before the test - that should have told him which test to perform.

yeah you'd think so wouldn't you... just thrown by the cat comment. we'll see what happens at the retest.  I haven't changed anything on the motor and know now that it's not running rich.  there's no oil being burnt either so something doesnt add up

[unburntfuelinthemorning]

Let us know what happens.  Are you staying with the car?  I always like to keep an eye on what they do.

[neon1991]

very odd,  stuck it on the tester and it sat there on tickover.. all was fine, hovering at 3% then all of a sudden it jumped to 4 and failed the first one.  there was a change in engine note so not sure of theres something a miss in my carb.  probably a bit worn and sucking some air in and the spike may have been a momentary point that the leak got restricted.  stuck it on the test for a second time and it passed at 3%.

 

bearing changed,  so a clean ticket :)

[Steve220]

I'd be inclined to give the carb a recondition.

[unburntfuelinthemorning]

Nice one - not off the scale this time then!

 

No harm in overhauling the carb as Steve220 says - might help avoid future problems.

[Retroman]

Good news...

 

What was he playing at before, clearly dodgy. Maybe find some where more competent and Mini freindly

 

I would say the carb is fine its more likely to be a misfire that caused the blip

 

Did you get a print out of the emissions this time round ?

[carbon]

Good to hear it has passed.

 

Do you have a fuel filter fitted just before the carb inlet?

 

Reason for asking is that a small bit of rust can stop the needle valve sealing, if this happens you typically get the carb flooding, but if it is only slightly passing then you could end up with rich mixture at idle.

[neon1991]

Good to hear it has passed.

 

Do you have a fuel filter fitted just before the carb inlet?

 

Reason for asking is that a small bit of rust can stop the needle valve sealing, if this happens you typically get the carb flooding, but if it is only slightly passing then you could end up with rich mixture at idle.

I don't but will do now!  got a reading of 3% which was a bit high towards the end of the test.  generally hovered around 2.5 - 2.8% Ive been on some fairly long drives and the plugs look an even brown. it does seem a bit lacking around the 60mph mark but if you nurse it through this then around the 70mph is normal in that you can push up to 80 if you wanted to get out of trouble (like pass that car that has decided that he doesnt want you overtaking him)

[Readers14]

I’ve always had problems getting mine passed on emissions as it has a decat (1994 1275).
Luckily it only does 300 miles each year so the tester passes it second time around.
I’ve been advised just to mention the decat before the test. Funnily enough I’ve got mine booked in tomorrow.
We’ll see what happens!

[Bat]

Hi,

I'm going to guess the tester just carried out a basic cat test going on the age of the car.

Obviously minis don't comply to that format and as said above he should have spotted there was no cat especially with the recent updates to the mot test.

Cheers