MOT absorption coefficient (how to pass emissions)

[saskak]

Hi All,

My car (Pug Partner, 2007, 1.6HDi, M59, 90bhp, no dpf) a badge diff. to the Berlingo just passed the MOT, but I might have to look into the emissions next time. The absorption coefficient that was measured was 2.64 l/m (3550l/min), 2.65l/m (2801l/min) and 3.00l/min (4449l/min). Mean abs. coef. 2.76l/m (zero drift 0). Engine temp was 61C, so a bit on the cold side. As it is 2007 the limit that applies is <3.00l/m.

The way I understand it, it is an opacity test, so it does not test specific parameters, just the colour. As mine is fairly close to the 3l/min limit, there is a bit of smoke there. The car puffs some smoke (blue-ish) on cold start up (morning), but it clears within 20sec and it does not smoke after. Well, looking at the abs. coeff. numbers it does smoke a bit, but not entirely visible in the rear view mirror.

Now, before anyone starts the usual, "italian tune-up", "block EGR", "Millers", etc., I would like to now what I can do to reduce the emissions without these.

New oil (total quartz eno ecs 5W30) new fuel, oil and air filters, EGR cleaned. This was done ~1month ago, i.e. before MOT. Intercooler cleaned ~1 year ago. As far as I can see, the only thing I can relatively easily do is check the turbo cartridge if it is passing oil and injector leak-off.

If anyone has recent MOT absorption coefficients in hand to share, it will be much appreciated.

One last thing, would it be permissible to have my oil catch can during the MOT? I know it is a modification that will reduce smoke, but is it legal in the eyes of the law.

Cheers,
saskak

[cancunia]

It does look a little high. IIRC from last Dec, my '08 1.6Hdi with 135k miles had an emissions sticker with 1.8 on it. I had painted over that by mistake, so the garage applied a limit of 1.5, which I think was too low for the registration date. In any case, it tested with a level of 0.5, again IIRC. Your catch can is a 'mod' but not to the emissions system, it might fail an MOT, or at least get an advisory, depending on the testing station.
A few weeks ago I was looking at Toyota Hiaces, from checking their MOT history, a few of them had failed the smoke test, then without any more than a couple of miles added had passed the same day. The general feeling on here was the fabled 'Italian Tuneup', so the engine & exhaust temperature will almost certainly make a difference.

[saskak]

It does look a little high. IIRC from last Dec, my '08 1.6Hdi with 135k miles had an emissions sticker with 1.8 on it. I had painted over that by mistake, so the garage applied a limit of 1.5, which I think was too low for the registration date. In any case, it tested with a level of 0.5, again IIRC. Your catch can is a 'mod' but not to the emissions system, it might fail an MOT, or at least get an advisory, depending on the testing station.
A few weeks ago I was looking at Toyota Hiaces, from checking their MOT history, a few of them had failed the smoke test, then without any more than a couple of miles added had passed the same day. The general feeling on here was the fabled 'Italian Tuneup', so the engine & exhaust temperature will almost certainly make a difference.

Thanks for that.
I guess the "Italian tuneup" will blow carbon particles from the exhaust, etc., so these will not interfere/block the light during the opacity test (basically light absorption coefficient from a calibrated source). What I was wondering if an injector is passing too much fuel, this will probably result in more soot and higher smoke.

[RJBingham]

Hello, I've got a 2007 Berlingo 1.6hdi 90hp, no dpf passed it's MOT in September @ Mean abs. coef. 1.86l/m it had about 130000 on the clock at the time.

[saskak]

Seems that mine was pretty high. I went through the old MOTs and all of them were ~<1 (one was even 0.2), but for most the measurement was taken almost straight after I brought the car in the garage. So, the car was really warm. This time, I brought the car in the morning and went through at ~16:15, so whole day and the oil temp reported was 60C. Shouldn't the mot centre do the measurements when the car is in operating temperature?
Maybe it is nothing to worry about.

Cheers,
saskak

[RJBingham]

I took mine first thing in the morning, but took it for a 20 minute drive first.

[cancunia]

Seems that mine was pretty high. I went through the old MOTs and all of them were ~<1 (one was even 0.2), but for most the measurement was taken almost straight after I brought the car in the garage. So, the car was really warm. This time, I brought the car in the morning and went through at ~16:15, so whole day and the oil temp reported was 60C. Shouldn't the mot centre do the measurements when the car is in operating temperature?
Maybe it is nothing to worry about.

Cheers,
saskak

There is something in the test procedure about the engine being at normal temperature when doing the test, but the testing stations probably work on a pass / no pass basis to save time & money (yours & theirs). If it fails there's always the opportunity to get things warmed up and try again, which is what I think happened with the Hiaces I was checking.

[saskak]

Seems that mine was pretty high. I went through the old MOTs and all of them were ~<1 (one was even 0.2), but for most the measurement was taken almost straight after I brought the car in the garage. So, the car was really warm. This time, I brought the car in the morning and went through at ~16:15, so whole day and the oil temp reported was 60C. Shouldn't the mot centre do the measurements when the car is in operating temperature?
Maybe it is nothing to worry about.

Cheers,
saskak

There is something in the test procedure about the engine being at normal temperature when doing the test, but the testing stations probably work on a pass / no pass basis to save time & money (yours & theirs). If it fails there's always the opportunity to get things warmed up and try again, which is what I think happened with the Hiaces I was checking.

Yes, that makes sense in terms of saving time. Next time I am booking my own MOT, kind of wait while your car is checked.

[cancunia]

Yes, that makes sense in terms of saving time. Next time I am booking my own MOT, kind of wait while your car is checked.

Yeah, book an MOT 'while you wait' & turn up 5 mins before it's due.

[saskak]

Yes, that makes sense in terms of saving time. Next time I am booking my own MOT, kind of wait while your car is checked.

Yeah, book an MOT 'while you wait' & turn up 5 mins before it's due.

I was thinking of constructing my own diy emissions sensor, of course not really calibrated and accurate, but kind of relative.
I was wondering if I can do whatever I do to my car, e.g. block EGR, oil catch can, etc., and go to an MOT centre and ask them to only test the emissions (no MOT), so I can test my sensor and car changes. I suspect they are a bussiness and at quieter times and some payment they would be willing to do it?