Failed MOT - Emissions

[Fredjohn]

As posted elsewhere I've failed the MOT on emissions: 4.3% ilo 3.5%. (UK SE non cat)

I cleaned the K&N filter and fitted new spark plugs and the reading dropped to about 4%.

I have yet to check the base timing and yet to adjust the "pot": Monday's job.

But I did run an Elanscan and the resultant file is attached. Can someone please help by interpreting the results compared to a previous scan done when the car was "OK".

To me as an untrained observer everything looks the same except for the coolant temp. In the old scan it goes to 75 then levels off as the fans cut in. In the most recent scan it goes to 110 before it levels off and the fans cut in (I heard them both come on at this point).

Is the fault with the CTS or with the fan sensor? I know that a faulty CTS can cause rich running. It only runs rich on tick-over: at 2500rpm the emissions drop below the required level.

Thoughts interpretation of scans help assistance gratefully received.

Elanscan set1.zip

motcheck2.zip

Thanks.

[GeoffSmith]

Can't see anything obvious John. The first scan from cold shows the thermostat operating at ~75°C when you've got a bit of airflow through the radiator. You stopped at ~320s and the temperature is starting to increase and would eventually hit 110°C when the fans kick in. You second scan shows the fans doping their stuff.
Best bet is to check base timing then adjust pot when they're doing the emissions test.

[Rambo]

Surely they won't allow you to do that in the middle of an MOT test will they ?? Unless you know a dodgy tester

[Fredjohn]

Surely they won't allow you to do that in the middle of an MOT test will they ?? Unless you know a dodgy tester

They let me back in and checked the emissions before actually doing the test. It had improved to 3.9-4% from 4.3%, but not enough clearly.

I have now checked base timing: it appears to be about right: I say appears as the sun is very bright, the timing light weak, my neck is cricked and the marking only just visible! The pulley groove (now marked in white paint) is about half way between the 10 and 20 marks. The car starts very easily in all conditions and the old plugs were all a good buff colour.

I have adjusted the CO pot (in service mode), 5 turns clockwise, but none of the wikiLEC references actually tell you which way to turn it to increase/decrease readings!!!!


I have also put in some injector cleaning fluid in the hope this will help. Next gas test 5pm Tuesday 16th Aug.

[maz_r]

Hi John,

Somewhere hidden away in my garage is a CO tester; I will dig it out and bring it on Thursday (all things being equal).

Then you will at least have a fighting chance of turning the pot the right way! Previous posts would indicate that the tester I have is pretty accurate, so fingers crossed you an get it close before the next test.

[John_W]

FredJohn,

Base timing should be 16 deg BTDC, and a good spark is needed (31 thou gap). Assuming your car is an SE, then the chip makes a difference too.

As to the pot, anti-clockwise leans it off, clockwise richens it. If you turned it 5 turns clockwise, the emissions should be higher, but 5 turns is way too much. Beware that the potentiometer has no end stops so you can turn away to your heart's content and nothing appears to happen. Although the pot can be turned forever, the actual adjustment effect occurs over about half a turn from the fully anti-clockwise position. If you were to remove the pot and measure it with a meter, it reads 270 ohms at the anti-clockwise extreme and >10kohm at the other extreme (I counted 21 turns clockwise).

The CO pot adjustment doesn't show on ElanScan, but you can use ElanScan to check which chip you have.

What chip are you running? To meet lower emissions targets, Lotus brought out a replacement chip (9930) to allow lower CO levels. If you still have the old chip (9929), you may not be able to achieve the necessary CO level, even with the CO pot on minimum adjustment (270 ohms, fully anticlockwise). See the service bulletin on http://ealanach.co.uk/elanchips/index.p ... &Itemid=11 . If you've got a Mountain chip, they're all based on the latest version of the Lotus chip.

John

[Fredjohn]

Martin, many thanks, will take you up on your offer, but my free retest limit expires Wednesday!

John: I have a UK SE with prom id 9929, according to elanscan. However I have an Everest chip. Does this modify it to a 9930, or do I need to acquire an upgrade 9929 to 9930 from elanchips?

Edit: Notice that a 9930 memcal is available from SJ Sportscars for £55+VAT + delivery. Part no A100E0097S

The garage did a quick gas test and sure enough 5 turns clockwise has made the reading 5% I have now turned it back the 5 turns plus another 7. Maybe overkill, but it's the right direction. I was aware of the max 20/21 turns. I have a multimeter so could take some resistance readings, but my 6ft frame refuses to fit behind the glovebox!
Try again tomorrow.

[dapinky]

John,

At the price for the lotus chip from SJ's, I would be going for an O2 sensor to make it closed loop, together with an appropriate everest map on a 1499 (S2) chip..... or for the time being, someone on here *may* have a 'standard' S2 chip that you could borrow (or even buy) until you could aquire the one you would prefer

Not sure of current prices for the sensor, but IIRC it's in the region of 30 quid.

[lotusflasherman]

Martin, many thanks, will take you up on your offer, but my free retest limit expires Wednesday!

John: I have a UK SE with prom id 9929, according to elanscan. However I have an Everest chip. Does this modify it to a 9930, or do I need to acquire an upgrade 9929 to 9930 from elanchips?

Edit: Notice that a 9930 memcal is available from SJ Sportscars for £55+VAT + delivery. Part no A100E0097S

The garage did a quick gas test and sure enough 5 turns clockwise has made the reading 5% I have now turned it back the 5 turns plus another 7. Maybe overkill, but it's the right direction. I was aware of the max 20/21 turns. I have a multimeter so could take some resistance readings, but my 6ft frame refuses to fit behind the glovebox!
Try again tomorrow.

I always remove the glovebox completely - only takes 10 seconds to get it out..

[John_W]

FredJohn,
If Elanscan says you still have a 9929 chip fitted, then that's your problem. You will likely never get the emissions low enough by turning the CO pot or anything else. As I said, that's why Lotus brought out the 9930 chip.

You say that you have a Mountain chip, so the easiest thing to do is fit it and, as it's based on the 9930 chip and not the 9929 chip, you should be able to pass the emissions test. I wouldn't buy a standard chip from SJ when you already have an Everest available, as that would be a backward step for performance.

John

[Fredjohn]

Many thanks for all the advice guys. The Everest chip is already fitted and has been throughout. If I understand correctly the fact it is fitted will allow greater pot adjustment despite the 9929 prom id shown by elanscan? So I should get the reading down below 3.5%.

I already have an O2 sensor in the garage . So all I need do is send my 9929/9930 Everest chip back and have it upgraded to a 1499 Everest. Or do I need a 1499 chip too? A bit confused on this point.

Short term adjust to get thru mot, long term fit O2 sensor and upgrade Everest chip.

[Tyger]

Just curious... do ALL cars have to pass these emissions tests over there? Here in NY state cars as old as ours are exempt from emissions testing.

[Saltire]

Just curious... do ALL cars have to pass these emissions tests over there? Here in NY state cars as old as ours are exempt from emissions testing.

It depends (as do so many other things) on the age of the car. When I had my 1972 Alfa Spider (twin Weber carburettors), the MoT station used to say that as long as they could see the back wall of the garage through the cloud of exhaust smoke, I'd passed

However, newer cars have stricter limits, and since catalytic converters became mandatory (1992, IIRC), they are even tighter. If you want a really riveting bedtime read, take a look at the official UK government guidance.

[HJ2]

My S2 needs emission testing. CO is max. 0.5 %
Somehow is was always 0.4% and then a sudden step over the years to 0.5% (so FAIL)
Then i detected a loophole in the system and took the blue pill...
In the Dutch MOT regulations there is a statement that IF the car is before december 2005 AND has a cat, than CO should be 0.5%
Since my cat is gone and it is not written on my car's paperwork, i state that i don't have a CAT so at the MOT station I pull the O2 sensor and it is tested open loop with the 3.5% limit and passes flawless!

OK, back on topic now
John, make sure that the car is HOT before testing CO levels.

[Fredjohn]

Henk.....yes always thoroughly warm it up.

Twiddled the CO pot a bit more anti-clockwise whilst I was at the garage with probe inserted (in the exhaust, not me!!), and lo and behold down to about 2.5%.

Removed probe, out of service mode, re-insert, fresh reading still 2.5%

happy days MOT for another 12 months.

Many thanks to LEC once again it shows how good it is. Particularly John-w for advising which way to adjust the pot!! When WikiLEC is fully back on line it needs to be edited to include this vital bit of info!!!

[lotusflasherman]

Just back from a successful MOT. Arrived few minutes early and switched lights & hazards on for last minute check and N/S repeater wasn't working, it was last night
Opened passenger door pulled out bulb holder and wiggled capless amber bulb and hey presto! Flashing light again and sorted.

MOT guy had arrived behind me as I put holder back in and he then drove it into the bay without delay.

I'm running an ECU with Everest chip from my SE on SORN and the CO was showing 3.54 in Red so a FAIL
I said I could adjust the pot or fit the other ECU that was in the boot but MOT guy suggested try removing the air filter, which I did, and it was then clocking between 3.49 in black and 3.51 in red ... until he made a minor adjustment to the wand position ... and we stayed in the black, just. Good man, I owe him a drink .

Brake balance was spot on 50/50 so re-greasing the sliders was worthwhile and figures for front, rear and handbrake were all OK so I got a Pass.

Just looked on the check-MOT website and see he's entered it as initially Failed on the N/S repeater before a Pass ... wonder whether that was to cover the time messing around with emissions
It was working when the test started.

[Rambo]

A pass is a pass is a pass

Still think you need to investigate that 3.5% CO level Phil. It seems excessively high and probably worth checking the base timing ? Or did I miss something ?

Personally, I always think it's worth doing a brakes service prior to an MOT. It doesn't do any harm anyway