The MOT is due soon and last two times it failed for emissions (1.9 tdi).

 

I wasn't there for the first one; they put something through the system and took it for a spin then it passed.

 

Most recent MOT they told me to drive it in 2nd at 40 for 5 minutes (4 times) which worked.

 

I have seen a bottle of Redex "MOT pass" stuff in Tesco.  Put it in when refuelling.

 

Is it worth it or just a load of rubbish?

Edited 15 November, 20205 yr by JamieH86

I would try achoil as much more superior product

 

 https://www.powerenhancer.co.uk/archoil-ar6400-d-max-professional-diesel-engine-turbo-dpf-cat-cleaner-concentrate.html

Yes, for a fiver it can't hurt.

 

I use it at twice recommended dose 50 miles before test, never fails.

The other method is that you can improve your emissions by taking the car out on a long/fast run.  Making sure that the engine is warmed up first, then keep the car in a lower gear (typically no higher than 4th) - and give the car some beans.

 

The Italian tune-up method - but this is a trick from old.  It used to be the case that the MOT tester took the car up and down the local bypass in 3rd - and then straight into the MOT tester emissions test with a hot engine.

Thanks all.

 

The bugger is working from home and not going out due to lockdown the car is doing 0 miles per week at the moment!

What's your driving style like usually? Does it just get driven gently?

 

Given that the MOT for a diesel is just a smoke test then it suggests a problem somewhere.

 

My previous 1.9 TDI Octavia (PD105) used to pass well under the limit.

For the most part in the last two years I lived in France in the country, so most roads are 50mph - not a lot of motorway driving or going faster than that.  Unusual to maintain above 20 on the rev counter for long.

In theory a lot is down to the quality of the fuel that you use. If you use fuel from the big fuel companies, the quantities of detergent additives ought to be fine, etc, etc.

 

Supermarkets and minor suppliers may have less of a reputation for quality fuel (as opposed to cheap fuel) to protect,and may cut corners as much as they think reasonable on detergency.

 

In your situation, I probably would give it a shot of additive and a bit of an 'Italian tune up' (engine suitably warmed up, of course), just in case it helps. It is probably more to do with what you do on the previous tank full, rather than the tank that you go in to the MoT with, though.

Another thumbs up here for archoils products a tank of the more expensive branded "super" diesel may help. I assume the car is serviced regularly and the air filter etc are in good order every little helps  now they test to plate limits.   

Yes it's got at least one service for every year of its life, oil and filters were changed four months ago.

 

I have just had it re registered to UK plates and when I spoke to the DVLA they said they'd accept the last MOT (French).   They did, and I have a V5C.

 

But the DVSA it turns out don't... so now it is registered and taxed but not MOTed, legally... limiting my options for taking it for a run!

Well it's been for an Italian tune up.

 

No idea about emissions yet but afterwards I only had to look at the accelerator and it was away... so that's an improvement anyway!

My 1.9 PD also failed MOT on emissions recently. Not surprising as this year it's mostly been confined to pottering journeys. 

 

0.8 limit on the VIN plate - failing at 1.2 average.

 

I ran the tank down low to 60 miles range, and then added a bottle of Redex Diesel treatment. Only chose Redex as I was in Wilco and saw it on the shelf, saves paying for delivery.

Ran the car really hard for a 20 mile trip there and back.

Then filled up with 1/2 a tank of premium diesel.

 

MOT easily passed a few days later at 0.6.

 

Having had a good read of the MOT manual, if the value on the VIN plate is not legible or not even there, then a pre 2008 turbo car reverts back to the default limit of 3.0 on the smoke test....

 

It always gets tested against 0.8, so no joy there!

 

When it failed the last MOT, the average reading was 2.3!    That was an average of two; they didn't bother with the third check.

 

After driving at 40 in second for 15 minutes, it passed with an average of 0.5, so quite a big drop.   That was without any fuel products.

 

This time round I'm not using the car daily like I was.   I filled up about 7 weeks ago and have still got 3/4 tank left, so I've added the Redex and will do a couple more 'Italian tune ups' before the MOT on Monday.

When a car get run around town a lot, exhaust soot builds up in various nook & crannies inside the exhaust system.

 

When the MOT tester does the smoke test, he floors it which blows out all the soot, which then gets measured with the machine giving a high soot reading.

 

It's always best to give the engine a good thrash before the MOT & blow out all the soot.

 

Get onto a fast open road, put your foot down in 3rd from 2000 revs & watch the cloud of black soot in the mirror.

5 hours ago, PipH said:

Get onto a fast open road, put your foot down in 3rd from 2000 revs & watch the cloud of black soot in the mirror.

 

Rollin' coal for a few miles

 

To be fair there's never any smoke out of the exhaust... but I'll do that anyway.

 

Luckily the mechanic is picking the car up for the MOT and has to go 20 miles or so to the test.  I'll tell him to do it in 2nd!

@Camlobe

With your theory more than half the vehicles in the UK must be running the possible not so good quantity fuel, the thing is that is not the case really as 'less expensive fuel' is not like Own Brand Beans or Digestive Biscuits.

There are no special additive packages in standard diesel or 95 unleaded in the UK from BP, Shell, Esso, Texaco etc over that from Morrison, Tesco, Asda,Sainsbury's, Costco etc.

You're probably right, and yet it "feels" like some places sell crapper fuel, that is less efficient by MPG.

 

I always top up in the morning; apparently fuel in cold underwater tanks is more viscous, meaning you get more in your tank (as the pump measures litres per second regardless of consistency).

The filling stations pay the tax and duty on the fuel as they get it delivered and pay for the fuel.

They then sell to you and collect the money for fuel and taxes. (Duty & VAT).

You are getting no extra through weights and measures and they are not giving any away, and you are paying for energy.

 

How cold is the fuel you are getting from in the ground tanks or from 'cold underwater tanks'?

No idea why I said underwater!

 

Underground, of course.   

 

Not especially cold... but colder than after it's had the sun on it of a day.

1 hour ago, JamieH86 said:

I always top up in the morning; apparently fuel in cold underwater tanks is more viscous, meaning you get more in your tank (as the pump measures litres per second regardless of consistency).

Fuel pumps and metering have always been positive displacement and the trading standards regularly check them to very fine limits.

 

If you have not yet worked out that the pumps flow less fuel per second if you squeeze the trigger a little less then you must have very smelly shoes & socks

On 25/11/2020 at 08:17, JamieH86 said:

It always gets tested against 0.8, so no joy there!

 

When it failed the last MOT, the average reading was 2.3!    That was an average of two; they didn't bother with the third check.

 

After driving at 40 in second for 15 minutes, it passed with an average of 0.5, so quite a big drop.   That was without any fuel products.

 

This time round I'm not using the car daily like I was.   I filled up about 7 weeks ago and have still got 3/4 tank left, so I've added the Redex and will do a couple more 'Italian tune ups' before the MOT on Monday.

My 2009 1.9 get tested to a plate value of 1.0 not 0.8 

On 25/11/2020 at 07:57, softscoop said:

My 1.9 PD also failed MOT on emissions recently. Not surprising as this year it's mostly been confined to pottering journeys. 

 

0.8 limit on the VIN plate - failing at 1.2 average.

 

I ran the tank down low to 60 miles range, and then added a bottle of Redex Diesel treatment. Only chose Redex as I was in Wilco and saw it on the shelf, saves paying for delivery.

Ran the car really hard for a 20 mile trip there and back.

Then filled up with 1/2 a tank of premium diesel.

 

MOT easily passed a few days later at 0.6.

 

Having had a good read of the MOT manual, if the value on the VIN plate is not legible or not even there, then a pre 2008 turbo car reverts back to the default limit of 3.0 on the smoke test....

 

My other car is a 1999 toyota land cruiser the plate limit is 1.3 it passed this in May at 1.11 but I wonder how many get tested to the 3.0 limit as the sticker plate has "fallen off"  

Well I'm a Redex convert now!

 

Not only did they not apply 3.0 l/m to the test, they didn't use 0.8.   Instead it was tested at 0.6 but came out at 0.22, which is the lowest I've ever seen it.

On 25/11/2020 at 20:57, e-Roottoot said:

@Camlobe

With your theory more than half the vehicles in the UK must be running the possible not so good quantity fuel, the thing is that is not the case really as 'less expensive fuel' is not like Own Brand Beans or Digestive Biscuits.

There are no special additive packages in standard diesel or 95 unleaded in the UK from BP, Shell, Esso, Texaco etc over that from Morrison, Tesco, Asda,Sainsbury's, Costco etc.

 I worked in the fuel additives industry a few years ago. We ran many field test vehicles to validate our formulations. A good additive package makes a huge difference, especially for keeping injectors and inlet valves clean.
Not all additives are the same, the biggest problem and hence cost is the development of heat stable detergents. The dose is important too some fuels have a keep clean dose, others (premium fuels) have a clean up dose.