MOT failure on emissions

[bluespeed]

I would appreciate some advice from the forum members.

 

My 2002/3 1800cc K series R300 on throttle bodies has just failed its MOT on idle emissions. The car does not have a distributor and has an ECU black plastic MBE type? ☹️

 

I am not sure if it is a faulty sensor some where is the system as I cannot, and the garage cannot get into the ECU to diagnose the problem. They have sent me away to sort it out but I am a bit of a loss as where to start. It certainly is running rich at tick over as you can smell the unburnt fuel.

 

Passed last year but injectors cleaned since then.

 

I now have 10 working days to get it sorted before a complete retest!

Simon N

 

 

 

 

 

[Stationary M25 Traveller]

Assuming the throttle bodies are balanced, sounds like you need to take it somewhere with suitable diagnostic/tuning equipment. Do I recall Northampton Motorsport as a local name for Sevens ?

[Jonathan Kay]

You could ask Ratrace in Potters Bar.

 

Jonathan

[Graham King]

BS, just a thought before you potentially spend a fair bit of money on maps etc. Last year at this time the external temp was approx 20 degrees warmer than it currently is, so the engine and cat would have been a lot warmer I would guess, was the cat up to operating temp when the test was done.

 

Are they a helpful garage, would they let you take it out for a good thrash first then immediately do the idle test?

 

Graham.

[NickK123]

Quoting Graham King: 

BS, just a thought before you potentially spend a fair bit of money on maps etc. Last year at this time the external temp was approx 20 degrees warmer than it currently is, so the engine and cat would have been a lot warmer I would guess, was the cat up to operating temp when the test was done.

 

Are they a helpful garage, would they let you take it out for a good thrash first then immediately do the idle test?

 

Graham.

 

Good point, which I concur. To get my Supersport R (with Throttle bodies) through the test I have to get the engine plus cat roasting hot. The current low temp cannot help.

 

 

[swsambler]

I have been discussing this with the MBE dealer in Yorkshire. He made the comment that this is often air bleeding into the exhaust before the Lambda sensor, thereby causing it to think it is running lean, causing the ECU to react by enrich ending the mixture. Suggest you check exhaust joints.

[YellowPeril]

I have a couple of thoughts that may help or hinder…

 

If you can smell fuel have you noticed unusually high fuel consumption recently? Mine dropped to 12mpg at one point so I replaced the throttle position sensor - it had failed and was telling the ECU to send max fuel through the system. I seem to recall that it is a fairly inexpensive Rover part (

 

Good luck.

 

[Peter G]

Simon

 

Where are you getting this done? I always take mine to Allon White (Morgan dealers) in Cranfield, can't promise they'll pass it if there's something amiss, but they are used to Caterhams up there, not all garages are.

[AndrewGP]

Quoting YellowPeril: 

.........Since then I have had verniers fitted to get the timing correct, had the throttle bodies balanced and had it remapped to improve driveability/fuel consumption/ease of getting an MOT.

Unfortunately I have only achieved 2 of the above and my last MOT was problematic, requiring a sympathetic MOT tester even after getting the engine hot on a warm July day.

 

I am confident that the mapping is as good as it can be and the fuelling is right – it has also been suggested to me that air is leaking into the system before the Lamda sensor but I am yet to test for this. Currently my only solution is to continue to find a tame Mot tester – not ideal........

 

 

To add fuel to the fire, I am in exactly the same position as this. My car is a Supersport R ie R300K spec. I did have the engine totally rebuilt last year, only the block, head and crank were kept, everything else was replaced so I know it's not the internals that are at fault. As such I'd also be really interested to find a solution

[Ivaan]

I believe some of the problem is caused by the cams we run and the overlap on the valve timings. The exhaust valves are still closing, when the inlet valves are opening and some of the FA mixture get dragged straight out of the exhaust.

 

If you have verniers, you can reduce the overlap, and the emissions should drop. I used to do this whilst the car was on test, then reset after a pass achieved.

[oilyhands]

In my experience even engines with massive overlap will run clean enough for an MOT test. Even if the majority of your map is correct it doesn't mean that the idle fuelling is close enough for an MOT pass so it may require a tweak. Air leaks are a major cause of failure for the reasons stated above.

 

I've yet to see an engine fail when the fuelling is mappable and the exhaust, lambda and cat are in good working order.

 

Oly

[Martin J]

My sigma struggled a little on MOT emissions but I had a helpful tester.

He found getting the end of his sampling tube as far up into the exhaust as possible made a huge difference & it passed easily then.

The theory being that it's that bit hotter further up the can.

[bluespeed]

Whow what a great response *biggrin*.

 

The THB have been balanced and the injectors cleaned recently.

I had Verniers fitted by Dave A (Oily?)., this was a great boost to mid range performance and has improved the car last year, she has not been through an MOT since.

 

However, I think there is a common thread developing here, I will go away and try to determine if there is an air leak from the exhaust manifold sucking in air, not the easiest things to tighten up if my memory serves me (knuckles took a good skinning last time). I will replace the gasket at the same time.

 

Any advice on how to get into the 2 corner bolts, scuttle end, would be helpful as I struggled to retighten these when I took the engine out and removed the exhaust in 2011/12 (pre last Mot).

 

I will provide feedback, when I have some, as to what was the solution.

 

I really appreciate the help and advice.

 

I was planning a remap this year but feel this fault is more fundamental to the running of the car and needs resolving first.

 

Off to find the right socket to have a fight with the exhaust bolts!

Simon N

 

 

 

 

Edited by - bluespeed on 2 Apr 2013 20:43:14

 

Edited by - bluespeed on 2 Apr 2013 21:23:24

[Stationary M25 Traveller]

I think I had to use an open-ended spanner and 1/6 of a turn at a time on the back one.

[BenF]

Simon

 

Let us know what you find.... as you know, I also have an R300K which runs very rich on idle and I wonder if I should be looking for an air leak pre-lambda sensor before I take mine to be mapped!

 

Ben

[bluespeed]

Ok Ben will do

 

Edited by - bluespeed on 2 Apr 2013 21:22:14

[7gineer]

Just when you thought you were alone

 

My '04 plate R300 K series (roller barrels) failed MOT miserably ☹️ on emissions today - readings of 6+ instead of 0.6 ish - so much fuel was coming out of exhaust it got into (and knackered) what I suppose is a filter module at back of testing machine.

 

It had been running a little less smoothly and wouldn't tick over as well as it had done but as not used regularly recently not easy to notice. Yes it is using lots more petrol.

 

Suggestions so far are faulty Lambda sensor, faulty water temp sensor (richening mixture even when water hot - certainly seems to run more smoothly when cold).

 

Only thing I have done recently is changed the hoses (so drained coolant) and refilled with plenty antifreeze. Couldn't see anything I could have left off, knocked, bent, broken etc.

 

MOT guy wondered why no tube on nipple on small black plastic box in front of ECU box on scuttle and no tube on what appears to be a sensor (3 bar inscription) at front of fuel rail on throttle bodies.

 

Would be grateful for feedback re missing pipes(s)?

 

Chasing diagnostics tomorrow.

 

 

 

 

 

[oilyhands]

The small plastic box is a MAP sensor which is not used on the R300 installation. The missing pipe on the fuel pressure regulator is only required on plenum based systems which run on MAP rather than alpha-n (TPS).

 

Oily

[bluespeed]

How strange my MOT team also asked almost exactly the same questions about the missing pipes. Dave A thanks for the answers. Mine also failed with the same readings at tick over at 6+.

 

I removed the tubular exhaust tonight and will replace the manifold gasket tomorrow There are signs of leakage on the old gasket hence the chance air could get sucked in upsetting the ECU.

 

Can anyone advise a good exhaust sealant paste to ensure there are absolutely NO LEAKS between pipes and gasket, gasket and block, and around 4 pipes as they enter the 4 into 1 collector pre Cat.

 

Is there anyway of telling if the Lamda sensor is working correctly with a DVM? ( I have two lamdas, one mounted in one of the tube exhaust pipes, which is not connected and one mounted in front of the cat which is ).

 

Will seal it all up tomorrow hopefully and head back for a retest Friday/Sat, I hope it passes as I want to drive her!

 

Would appreciate hearing about your diagnosis story Mr 7gineer.

 

Simon N

[Stationary M25 Traveller]

Paste like Firegum is not good for a Seven type installation. It will harden and fall out.

 

As long as the face of the block is not scored and the flange of the manifold pipes is not twisted or damaged, this will seal ok.

 

You could use a light smear of silicone sealant (ordinary clear stuff will do) on the ends of the primary pipes before pushing them into the collector. Not too much, and not within 25mm from the end. You don't wan't excess silicone in the catalytic convertor. It acts as a lubricant and will seal the gap.

 

You could swap lambda sensors over ... may have to extend the cabling.

[Fil M]

it is worth ensuring your TPS and roller barrells are set exactly to those recommended by Caterham. My 1800cc k series (full R conversion with Roller Barrells. MBE ECU etc) was running lumpy and rich and when given a pre test for MOT at a local garage was heading for a fail. I have found that two individual garages including a 7 friendly one set them up other than the Caterham recommended way. The tools needed are a vaccuum guage and volt meter. The settings are as per this blat chat page ...

 

http://www.blatchat.com/T.asp?id=56472

 

enter this in your internet explorer search bar to get to the page... dont enter it on the blat chat or other net search engine (google,virgin etc) because it will fail to find it. Good luck

 

PS ... with the right tools its very easy to do.

 

 

[Stationary M25 Traveller]

... or hit this link.

[AndrewGP]

This thread has motivated me to also try and find a solution I sort of have a solution which involves a decat pipe and a friendly MOT place but that's not ideal

 

Unlike bluespeed, I only have one lambda in the no 4 primary. This is obviously upstream of the 4-1 collector, so although this shows evidence of air-leaks due to soot, the air-leaks themselves can't cause the ECU to change the fueling.

 

Am I alone in having a single lambda?

 

Anyway, of to check the TPS voltages, will report back later on.

 

Edited to say TPS voltage is 0.404v at the throttle idle position. Back to square one then as this seems to be the correct value!

 

Edited by - grenpayne on 4 Apr 2013 10:09:25

[Stationary M25 Traveller]

Cars only have one lambda sensor. Previous poster probably moved it to collector for better mix but left old one to plug hole.

[7gineer]

Good morning all

 

Thanks for the recent advice

 

On recommendation of Andy B (Tech 7) I spoke to Rob Singleton of Boss Racing (nr Brands Hatch) formerly with Caterham.

 

Over the phone he said probably roller barrels out of adjustment.

 

Apparently Caterham struggled big time with roller barrels to get the emissions down to MOT acceptable standards.

 

Will be taking mine in on Monday to (hopefully) sort.

 

Will let you know.

 

Had a look at exhaust manifold last night. No signs of leak but looks real ******* to get at rear nuts.

 

Only have one Lamda sensor on rear downpipe. There is a plugged hole on the pipe.