Exhaust emission on the MOT.

wiff2110

wiff2110

Joined
Aug 4, 2011
Posts
103
Likes collected
53
Location
West sussex
Funster No
17,635
MH
Swift Bessacarr E460
Exp
15 years
My 2008 Fiat bessacar motorhome struggled to get through the MOT with the exhaust emissions test, I notice it does blow black smoke at times and the exhaust pipe has a fair amount of soot present, so how can I remedy this situation before the next MOT is due. Looking on Utube one person uses a cleaning fluid put in with the oil and also put a water hose up the exhaust, runs the engine at various power settings and turn on the water into the exhaust system to clean out the soot. Anybody done this procedure? or recommendations of a garage that will cure my emission problem. At the moment I’m using Redex added to the diesel but don’t think that is helping.
 
Sort by date Sort by votes
I use millers additive and give it a double dose a week before the mot and on the day I drive it to the garage like I stole it, just keeping the revs up is good enough and have had no problems…

www.halfords.com

Millers Diesel Power Ecomax 500ml | Halfords UK

Shop the latest Millers Diesel Power Ecomax 500ml cetane booster & detergent adds up to 4 cetane numbers to diesel at Halfords UK
www.halfords.com www.halfords.com
 
Upvote 0
Just smiffy said:
I use millers additive and give it a double dose a week before the mot and on the day I drive it to the garage like I stole it, just keeping the revs up is good enough and have had no problems…

www.halfords.com

Millers Diesel Power Ecomax 500ml | Halfords UK

Shop the latest Millers Diesel Power Ecomax 500ml cetane booster & detergent adds up to 4 cetane numbers to diesel at Halfords UK
www.halfords.com www.halfords.com
Click to expand...
Hi Smiffy, I’ll stop using Redex and give this a try on my next fill up. Can I ask if your exhaust pipe is clean or has it got a coating of soot.?
 
Upvote 0
Black smoke can be caused by over-fuelling by worn injectors, or a dirty air filter .. or burning oil caused by a worn engine ..

what is the millage, when was it's last full service ?

more info here

Black Smoke Cause Impact and Prevention

Incomplete combustion occurs and soot is formed when there is an overabundance of fuel (both diesel fuel and lube oil), insufficient residence time in the combustion zone, and/or non-availability of sufficient oxidants. Over-fueling is the primary cause of black smoke from the exhaust of a heavy...
360.lubrizol.com 360.lubrizol.com
 
Upvote 0
wiff2110 said:
My 2008 Fiat bessacar motorhome struggled to get through the MOT with the exhaust emissions test, I notice it does blow black smoke at times and the exhaust pipe has a fair amount of soot present, so how can I remedy this situation before the next MOT is due. Looking on Utube one person uses a cleaning fluid put in with the oil and also put a water hose up the exhaust, runs the engine at various power settings and turn on the water into the exhaust system to clean out the soot. Anybody done this procedure? or recommendations of a garage that will cure my emission problem. At the moment I’m using Redex added to the diesel but don’t think that is helping.
Click to expand...

Give your van a dose of Forté Advanced Formula Diesel Treatment and an Italian tuneup.

Forté diesel additives are very good and not your usual snake oil. I have used Forté diesel additives in the past with good results.

www.forteuk.co.uk

Advanced Formula Diesel Treatment - Forté

Forte Advanced Formula Diesel Treatment cleans the whole fuel system pre and post combustion. It improves overall engine power and efficiency, as well as considerably reducing costly down time and component replacement in direct and indirect injection engines.
www.forteuk.co.uk www.forteuk.co.uk

Subscribers  do not see these advertisements

 
Upvote 0
As above, dose it up with forte in the diesel. Run the tank down a bit and put in the additive followed by a couple of gallons of diesel. Then take it out for a good drive on dual carriageways and keep it down a gear where you can to increase revs. You will push all the muck from the injectors and make it burn cleaner. I suggest doing this twice, even a week or two apart for best results. Then do it again next year a week before the MOT. And warm the van up well before arriving just on time for the MOT appointment. Many older diesels smoke a bit on first start from cold.

Don't be tempted to put a hosepipe up the exhaust as it will do more harm than good usually if not done right. The only exception is when flushing out a blocked DPF, but that is done from the other end
 
Upvote 0
A new air filter element just before the mot possibly, during wet weather if the van is stood the paper element will draw damp and marginally restrict air flow. Not by a lot but it all counts. I did get an older van through that failed on emissions by putting a K&N element in !
 
Upvote 0
Guigsy said:
Unlike many other engines (Ford, VW, etc) I didn't think the Iveco/Fiat 2.3 had many EGR issues?

Is it burning a lot of oil?
Click to expand...
A lot of the earlier fiat and iveco engines had big EGR issues. Often caused by the scuttle leak messing up the throttle body

Subscribers  do not see these advertisements

 
Upvote 0
scotjimland said:
Black smoke can be caused by over-fuelling by worn injectors, or a dirty air filter .. or burning oil caused by a worn engine ..

what is the millage, when was it's last full service ?

more info here

Black Smoke Cause Impact and Prevention

Incomplete combustion occurs and soot is formed when there is an overabundance of fuel (both diesel fuel and lube oil), insufficient residence time in the combustion zone, and/or non-availability of sufficient oxidants. Over-fueling is the primary cause of black smoke from the exhaust of a heavy...
360.lubrizol.com 360.lubrizol.com
Click to expand...
The mileage is 21000, oil and filter changed at 19600, it doesn’t use any oil between 5000 mile change of oil. I will remove the air filter and check it but it was last replaced at 19000.
 
Upvote 0
Has the engine been remapped?

We had our 2011 B544 2.3 Multijet remapped by Superchips last year and it failed the MOT on the smoke test - it should have been less than .91 but the lowest the MOT garage could get it (after spending money on several engine cleaners and clocking up another 1,000 miles keeping the revs at circa 2500) was 1.49. The garage said it was the remap and after a few conversations with Superchips they agreed to remove it and once done I went to the MOT station the next day and guess what the smoke test went down to .21! Superchips did eventually refund me the full cost of the Remap but I agreed to pay the £80 call out to put the original Map back onto the ECU which was fair in my opinion as I don't think they normally have issues. I thought it may be worth a mention to you given my recent experiences.

And ours was blowing out black smoke when on full revs and bouncing off the rev limiter which was a bit of a giveaway to it being remapped. It shouldn't 'bounce' of the limiter but just reach peak revs with a smooth consistent exhaust note.

Subscribers  do not see these advertisements

 
Upvote 0
Simonnsj said:
Has the engine been remapped?

We had our 2011 B544 2.3 Multijet remapped by Superchips last year and it failed the MOT on the smoke test - it should have been less than .91 but the lowest the MOT garage could get it (after spending money on several engine cleaners and clocking up another 1,000 miles keeping the revs at circa 2500) was 1.49. The garage said it was the remap and after a few conversations with Superchips they agreed to remove it and once done I went to the MOT station the next day and guess what the smoke test went down to .21! Superchips did eventually refund me the full cost of the Remap but I agreed to pay the £80 call out to put the original Map back onto the ECU which was fair in my opinion as I don't think they normally have issues. I thought it may be worth a mention to you given my recent experiences.

And ours was blowing out black smoke when on full revs and bouncing off the rev limiter which was a bit of a giveaway to it being remapped. It shouldn't 'bounce' of the limiter but just reach peak revs with a smooth consistent exhaust note.
Click to expand...
No it’s not been remapped.
 
Upvote 0
Our 55 plate Transit has always been just within the emission limits. After a good run out and a dose of Redex fuel system cleaner in the tank and top up with decent diesel.
It shows how the emission limits have changed because my Landrovers and the N Reg Transit with twice the milage never failed the smoke test. Saying that the rust issues probably distracted the tester.
 
Upvote 0
wiff2110 said:
Hi Smiffy, I’ll stop using Redex and give this a try on my next fill up. Can I ask if your exhaust pipe is clean or has it got a coating of soot.?
Click to expand...

I use millers regularly on my bmw and van, van is 12yrs old with 124k and the mot man said emissions are insignificant .01% or something like that, in other words it can’t get much better…

I use millers every other fill and just before mot I make sure it is well warmed up at least an hour and give it a good blast down the duel carriageway ..
 
Upvote 0
Mine was blowing out black smoke, and soot marks along side and up the back. My EGR (exhaust gas recirculation) valve was stuck open. The vehicle doesn’t know this as it is dumb to the operation of the EGR. And just assumes it is working as it has been requested by ECU.
 
Upvote 0
21,000 in 15 years implies only short journeys which may be a reason. My motorhome is of similar vintage but much higher mileage with no problems. Suggest a nice run down to southern Spain to clear out the cobwebs.

Subscribers  do not see these advertisements

 
Upvote 0
How do you drive ?
A turbo diesel needs a good clean out to clear the soot, if you always short shift and never push the engine then it can fail the emission test.
On the next drive if you are about to shift 3rd to 4th but just leave it for another 1000rpm and it leaves a massive black cloud behind you then it just needs an italian tune up.....but if not it could also mean the mot driver person isn't using the throttle as it needs to be
 
Upvote 0
the early x250 have problems with the egr being just controlled by vacuum and no feedback (earlier models have problems with throttle body (corrossion from leaky scuttle). These are improved in the x290 but come the twin egr we get new problems, with the classic P0401 egr code actually indicating the LPEGR cooler is blocked. (but Fiat pro insist on replacing a perfectly good valve, its on the sheet) Landy Andy and busbuddy have the nail on the head. I use Millers at each fill up and Liqui Moly diesel purge anually and also not afraid to hold onto revs. I also have a perfectly clean exhaust.
Do cleaners or additives work ? yes i tested injector variances on my skoda before and after cleaning and got stunning results that ive posted previously. Not stunning on the Duke as I have a injector playing silly buggers. As indicated by variances and when i put a sillyscope on them a very knowledgable guy says so, but i cant get to backprobe the crankshaft sensor or know the ECU pinouts to help his diagnosis.
 
Upvote 0
busbuddy said:
How do you drive ?
A turbo diesel needs a good clean out to clear the soot, if you always short shift and never push the engine then it can fail the emission test.
On the next drive if you are about to shift 3rd to 4th but just leave it for another 1000rpm and it leaves a massive black cloud behind you then it just needs an italian tune up.....but if not it could also mean the mot driver person isn't using the throttle as it needs to be
Click to expand...
Hi buddy, the motorhome always has a long drives of 25 miles or more never short runs around the block. As I said since the MOT I’ve been using diesel Redex additive but maybe it’s time for me to use Shell or BP instead of Tesco’s for cheaper fillup
 
Upvote 0
25miles is a short run in my opinion . Try 2-300 miles on a good motorway at 60-70mph. Do that for 4 days and you will be in Spain Hola.
 
Upvote 0
When I was working on the buses we used to run the Leyland Tigers in a low gear up the duel carriage way to get them as hot as possible. Pressure wash the engine to make the oil leaks less obvious then straight in to the test centre. The test was always first thing in the morning before the oil leaks became beyond the limit to pass.

Subscribers  do not see these advertisements

 
Upvote 0
bigwood said:
When I was working on the buses we used to run the Leyland Tigers in a low gear up the duel carriage way to get them as hot as possible. Pressure wash the engine to make the oil leaks less obvious then straight in to the test centre. The test was always first thing in the morning before the oil leaks became beyond the limit to pass.
Click to expand...
Fortunately no oil leaks on my engine.
 
Upvote 0

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top