Hi,

How much smoke is too much on a Fabia vRS? I noticed this morning accelerating uphill a lot of smoke out the rear window.

Its not normally that smokey, will pulling uphill make it smoke a lot more, couple of miles later on the flat I can't see any smoke.

D

Could it be the exhaust system clearing itself out under load? I had my non-vRS 1.9 MOT'd yesterday, and it produced a fairly large cloud of smoke when they did the initial "practice" smoke test, although it doesn't normally smoke that I've noticed (or been told about), but there again, I drive fairly sedately. I know that running it up a hill will load the engine more, so ...

What revs were you doing when you noticed the smoke?

I sometimes notice mine smokes when accelerating hard, off-boost (under 2K rpm). It stops when the turbo kicks in.

Edited 10 August, 201015 yr by Jim H

Mine has been smoking a bit recently, was thinking maybe a mini service might sort it out?

mine doesnt seem to smoke at all when it is off boost. the only time it really smokes is when i have been taking it steady for a while then i boot it, or when it gets above 3500rpm on flat out throttle. but its hardly visible in the rear mirror.

mines smokes like a a chain smoker due to the map I have had. Before that thou I had a little bit of smoke when drivering hard, unless you drive slowley for a while ie a few days then drive hard you will get a lot of smoke out the back for a few seconds!! I am sure someone will correct me if i am wrong

Don't worry all diesels pre particulate filters kick out soot when they haven't been booted for a while. I think ours are more obvious because the exhaust doesn't point to the ground so it gets sucked onto the rear screen. Good fuel and the millers seems to cut it down abit.

Regards Chris

Don't worry all diesels pre particulate filters kick out soot when they haven't been booted for a while. I think ours are more obvious because the exhaust doesn't point to the ground so it gets sucked onto the rear screen. Good fuel and the millers seems to cut it down a bit.

Regards Chris

I agree. Also check your air filter to see if it;s clogged. An after-market panel filter (K&N, Green, etc) helps, as well as a bigger intake pipe.

how much smoke is allowed for a mot also would adding millers help reduce the smoke

I think mot test for smoke at idle

Matt

I think mot test for smoke at idle

Matt

thank ****

I think mot test for smoke at idle

Matt

You think wrong.

The MOT testers rev the car up to maximum revs and tests the governor! They also rev it fast, but none of the tests are done under any load. See part B of this. The Testers Manual - Exhaust Emissions - Compression Ignition

Ah ha, this is my department. They smoke test at about 2,500rpm not full revs. Used to be at full throttle but there were a few broken dervs in the early days of smoke testing. You have nothing to worry about at the test.

I think mot test for smoke at idle

Nope - what Jim H said is correct - they rev it to the red-line area 3 times with a wand up the exhaust pipe, as well as doing a "fast idle". A pass reading is anything under 3.0 - mine produced a visible plume of very-soiled-dishwater-coloured smoke that was probably about 6' cube before dispersing on the first run (probably because I don't rev it that high, so despite a motorway run beforehand, it wasn't full cleared-out), which still only measured 2.0 on the read out - the subsequent runs produced little if any visible smoke.

Nope - what Jim H said is correct - they rev it to the red-line area 3 times with a wand up the exhaust pipe, as well as doing a "fast idle". A pass reading is anything under 3.0 - mine produced a visible plume of very-soiled-dishwater-coloured smoke that was probably about 6' cube before dispersing on the first run (probably because I don't rev it that high, so despite a motorway run beforehand, it wasn't full cleared-out), which still only measured 2.0 on the read out - the subsequent runs produced little if any visible smoke.

Well they should not be doing that. 1/2 the the redline engine speed is adequate for the test, most derv's redline at about 5krpm. If they are doing that to your car you should go to another tester.

Well they should not be doing that. 1/2 the the redline engine speed is adequate for the test, most derv's redline at about 5krpm. If they are doing that to your car you should go to another tester.

Err, according to VOSA, they should. All diesels should first have the engine revved to the lesser of either 2,500rpm or the half-way to the redline area to give it a bit of a clear-out. For older vehicles (pre-1979), the test should be conducted by raising the revs to the afore-mentioned figure. For newer vehicles (post-1979), the test is conducted by sharply (and briefly!) applying full throttle, and taking a reading - if the result is under 1.5, it instantly passes, otherwise a rolling average of the previous 3 readings is taken, and it passes when the average is at most 3.0 (2.5 for a non-TDI), or 6 readings have been conducted (fail).

Link:

http://www.dvtani.gov.uk/uploads/customerservices/DieselandCATleaflet.pdf

http://www.dft.gov.uk/vosa/repository/Diesel%20Smoke%20Test%20Card%20July%2009.pdf

Unless I'm missing something..?

EDIT: I'm assuming "rev governor" means red-line area...

Edited 11 August, 201015 yr by martinch

Looks like my MOT tester is treating my car as a pre '79 model, how nice of him. Better stick with him for testing until he retires.

Looks like my MOT tester is treating my car as a pre '79 model, how nice of him. Better stick with him for testing until he retires.

Hehe ... yeah, it didn't strike me as being too kind when I saw the test procedure!