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Literally, white van man
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Discussion Starter · #1 · (Edited)
Hello knowledgeable peeps,
So, the story so far….
2.5 tdi AJT, 2002 plate van, 250k miles
Regularly serviced 5w/40 quantum oil. PP0.5 nozzles and remap
Diesel Rhino at 1%
Esso standard diesel
Slight oil smoke (blue grey)
Black smoke on full throttle from low revs, visually not excessive and pretty consistent over the last 3 years.
vagcom shows no fault codes
vagcom timing at 53-59 (bang on/slightly advanced)
IQ 8.8-9.0 (set at highest adaption number so I am unable to decrease it further electronically)
The timing was checked before the MOT, the IQ after and adjusted down to 8.8-9.0, previously was 11.2.
previously has had the ‘hammer mod’ iirc

So, failed the MOT on emissions, 2.74 ppm (limit 0.8ppm) on first/fast pass, and test aborted.
this result was after a boost of diesel rhino (150ml into1/4 tank Esso standard diesel) and several hard Italian tune up accelerations before dropping it at the test center
The tester ‘declined carrying out further smoke tests’ for fear of clogging up his machine 😶
My thoughts were:
Black smoke = too much fuel and/or not enough air.
I can’t change the air (standard air box and filter) therefore ‘reducing the fuel’ is the way to go. Looking through many many posts it seems that my IQ is high, but I have ‘run out’ of electronic adjustment.
Is the way ahead to ‘reverse’ the hammer mod?
I believe the van was mapped on standard tired injectors, then had PP 0.5 injectors, hammer mod and then remapped.
All was good until the change in the MOT emissions (legacy rules 3. limit) now I’m trying to get down to 0.8ppm)

It’s in for a retest this morning, I can’t visually see much difference (it is possibly slightly better but that could be wishful thinking)

On the assumption it fails again, I’m thinking that getting the IQ down will improve things, and as I’m at the adjustment limit on vagcom I need to reverse the hammer mod, I have ordered the security triangle socket to allow me to attempt it.
Can anyone in the know provide guidance/advice that will steer me in the right direction?
Do I need to set the IQ to mid adaption before the reversal of the hammer mod? What adaption figures/range is there? (What figure is mid range?)

Sorry for the rambling on

Any help or thoughts would be much appreciated

Cheers in advance

Fatboy

(Edited to correct legacy limit)
 

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One quick way to get around it is to remove the emissions stivker frome the slam panel .

That will set your emissions limit at 3.0 , not 0.8 .
No good for your retest as they test to the original limit , but ok if you need a complete new test .

👍

Edit ,

What was the oil temp reading when it was tested ?

Should be 80 degrees or over
 

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Never going to achieve 0.8 on a proper test, that's close to the limit my 2014 dpf equipped caddy. A older non dpf van won't make that number when the test is carried out with full accelerations.
As above remove the corner off the chassis plate with the test value and book a mot somewhere else

Sent from my SM-A528B using Tapatalk
 

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Never going to achieve 0.8 on a proper test, that's close to the limit my 2014 dpf equipped caddy. A older non dpf van won't make that number when the test is carried out with full accelerations.
As above remove the corner off the chassis plate with the test value and book a mot somewhere else

Sent from my SM-A528B using Tapatalk
You’d be suprised .

My 2000 my 2.5tdi goes through at 0.5
My mates ‘98 1.9 tdi polo goes through at 0.7 .
Both have over 200k on them .

It seems harder to get higher mileage DPF stuff through the test than anything else .
 

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Literally, white van man
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Discussion Starter · #7 ·
Thanks everyone, it’s in now but the drive to the mot station wasn’t encouraging 🙄
I was under the impression that once tested at the ‘new limit’ it was recorded on the DVLA system against that limit forever, wherever it’s tested?
I’m happy to, ahem, ‘accidentally damage’ the sticker s the 0.8 is unreadable but would rather get the actual figure down.
when tested last year it went through at 0.24 but I didn’t see him do the test, so it may have been the 6 cycles (or did I imagine that test?)
The oil temp was recorded as 62 with a stated lower limit of 60 iirc, I’ll check when I get the van back later. It was well warmed up though, he had it for about 50 mins, I saw it running for The last 15 mins out of the 50, immediately before I dropped it off it had 30 mins plus of normal driving with some Italian tune up.
I suppose my question is, will reducing the IQ (by whatever means) improve the situation?
I’ll post later with results, one way or another
😂
Thanks again for the responses 👍🏻
Fatboy
 

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No , it’s not recorded for ever , just for the retest .

62 is too low , he should have been prompted to try again when the temp is above 80 by the emissions machine .

It can’t be failed at anything below 80 degrees .


Can’t say 100% , but I’m guessing the test wasn’t carried out to VOSA test standards .
 

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Literally, white van man
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Discussion Starter · #9 · (Edited)
I have to confess I wasn’t overly impressed with the testing when he said 2.74 would block up his machine, if no sticker limit is 3.0 then surly his machine should cope?
I don’t know how it works, is the same machine used for diesel and petrol engines? Isn’t it an optical test? So the probe ‘looks’ for the known amount of light and particulate in the exhaust ‘stops’ the light getting to the reader, so clogging up is probably soot on the sensor, which should be wiped clean before each test anyway?
I don’t know though.
waiting is frustrating, the test place is ‘trying’ to fit me in if they have time, and I am grateful for this, I have a little time left on the old MOT but I would obviously like it sorting out before I ‘have’ to.
Triangle socket should arrive tomorrow, see how it gets on today.
I have a mate of a mate who is a current tester, (it’ll be going to him next time 😐) and he confirms that if missing or unreadable the legacy limit is applied……(at the moment) I hope nothing happens to mine anytime soon 🫣
I’ll update later
Cheers everyone
Fatboy
 

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Literally, white van man
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4,076 Posts
Discussion Starter · #10 ·
Update, of sorts.
It passed 👍🏻
Fatboy is happy 😁
Fatboy, ex RN Grubber Tiff is deeply suspicious, a variety of reasons but is willing to accept the pass. 🤔
The question still remains though.
Will reducing the IQ by whatever means reduce the black smoke?
My idle mind did wonder if by reducing the IQ the temps in the engine would increase (less cooling effect of fuel in the cylinder and on the piston)
It’s not like I’m thrashing it everywhere, I mostly drive like a Nun.
if I get any further thoughts or responses (from other forums) and have a result to report back I will.
Thank you for all of your responses 👍🏻

Fatboy
 

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2,783 Posts
The hammer mod is a bodge that's difficult to reverse as the pump calibration is now lost (unless you scribed a reference line before wacking it) ; a good mapper can easily adjust the IQ ratio from a calibrated pump - S/H pumps are plentiful - I'd do it properly & swap the pump out.

My 160 BHP AJT runs the United Diesels version of 0.5s (guess who supplies them..), smoke at recent recent MOT was 0.22, test limit applied 1.8. There is no smoke (was mapped by the huge man himself in Barnoldswick), any smoke would be wasted fuel.


HH
 

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Yes , it’s an optical test .

We won’t put anything on the machine that has heavy Black smoke , but happy to test anything upto around 5.0 , after that it can need more regular cleaning .

Glad it’s finally passed .

👍
 

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the problem with kerosene is its very bag for the fuel pumps veg oil is ok at 50% max in warm weather
Both true, Parrafin or Kerosene as some call it these days used to be blue, remember the adds (if you are old enough) “Boom Boom Boom Boom, Esso blue” these days it aint as it carrys the red diesel stain to allow for being dipped and found. Diesel engines will run fine on it but there is no lubricant in parrafin so there is a need to put some in, most used to put about 15 percent engine oil with it. But as said, illegal.
My old 2002 Mitsubishi used to run on 100% fresh cooking oil in the summer and 50% in the winter.
 

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Full of Cr*p....
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My old 2 1/4 S3 petrol Landie (ex military) came with an instruction book for setting the timing to use parrafin....I think it was 3 degrees AFTER TDC.
It had twin tanks, so started from cold on a tank of petrol, once warm switched over.
This was when parrafin was a quarter the price of petrol (that was also only one pound a GALLON).
It ran OK.....but the fumes used to come in the tailgate (anyone who has had an old Landie would know how good the seals were!), and left "pink" clouds behind....especially on a trip to Scotland for Christmas.

When my old man was in the RAF, he used to fill his Austin 7 straight from the aircraft fuel tankers....but had to do a "de-coke" every month! (Don't think he EVER mentioned buying a new head gasket though......)
One time he forgot to put water in the engine....Friday, drove the 150 miles from camp to home, and couldn't turn the engine off! (Glowing red in the dark.)
Brakes were useless, so had to drive into the garden wall to stall it!
Tough old engine....next day he put water in, evening after he drove back to camp.
Imaging doing that with a modern engine?!?!
 

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My old 2 1/4 S3 petrol Landie (ex military) came with an instruction book for setting the timing to use parrafin....I think it was 3 degrees AFTER TDC.
It had twin tanks, so started from cold on a tank of petrol, once warm switched over.
This was when parrafin was a quarter the price of petrol (that was also only one pound a GALLON).
It ran OK.....but the fumes used to come in the tailgate (anyone who has had an old Landie would know how good the seals were!), and left "pink" clouds behind....especially on a trip to Scotland for Christmas.

When my old man was in the RAF, he used to fill his Austin 7 straight from the aircraft fuel tankers....but had to do a "de-coke" every month! (Don't think he EVER mentioned buying a new head gasket though......)
One time he forgot to put water in the engine....Friday, drove the 150 miles from camp to home, and couldn't turn the engine off! (Glowing red in the dark.)
Brakes were useless, so had to drive into the garden wall to stall it!
Tough old engine....next day he put water in, evening after he drove back to camp.
Imaging doing that with a modern engine?!?!
Great story mate. No they wouldn't last a hundred yards these days.
 
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