roadrunner
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| posted on 21/3/10 at 08:54 PM |
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Diesel teething problems
I've had my VW Bora for a week now , and i finally had a chance to get out for a proper drive this weekend.
My first issue is when accelerating in a high gear at low revs the car judders and shakes, it does do it in lower gears, it's just more
noticeable the higher the gear and lower the revs. It feels like it might be miss firing but yet it pulls really well in the low gears. It also seems
to struggle to pull out of the very low revs in a high gear and it is not as frugal as i thought it might be.
Secondly, the air flow sensor tripped out. Now i know there is an issue with the VW sensor. Is it an easy fix, or am i going to replace it and have
the same problem as i have already got.
By the way, it's the 150 version if that makes any odds.
Thanks in advance .
Brad
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skinned knuckles
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| posted on 21/3/10 at 09:01 PM |
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try an engine treatment. my GL320 merc has done 48k and was starting to get a bit sluggish and misfiring a bit at the bottom of the rev range. after
one treatment it is like a different car. sharper throttle response, more willing to rev and much fater acceleration. best £15 i ever spent in
halfords.
A man isn't complete until he's married, then he's finished
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zilspeed
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| posted on 21/3/10 at 09:04 PM |
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Lugging in high gears with low revs absolutely kills dual mass flywheels.
Using a lower gear dances around the vibration issue quite nicely.
It's also true that torquey as they may be, VAG diesels really don't like doing much below about 1900rpm.
Hope your flywheel is ok.
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Andy S
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| posted on 21/3/10 at 09:07 PM |
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For Diesel treatments try
United Diesel
Great Stuff and really helpful guy anything Diesel related.
Andrew
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roadrunner
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| posted on 21/3/10 at 09:08 PM |
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quote:
Originally posted by zilspeed
Lugging in high gears with low revs absolutely kills dual mass flywheels.
Using a lower gear dances around the vibration issue quite nicely.
It's also true that torquey as they may be, VAG diesels really don't like doing much below about 1900rpm.
Hope your flywheel is ok.
It's not that bad that it would damage the flywheel.
I have just looked on Ebay at new MAF sensors, and they say a faulty air flow sensor could give lumpy running.
Whats your thoughts on this.
Brad.
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nick205
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| posted on 21/3/10 at 09:25 PM |
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Worth asking the question - are you new to diesels and more so modern diesels?
I went from petrol (205GTI) to a Leon 150 1.9 TDI and it took me a while to gel with it. My current Passat 140 2.0 TDI is the same and really
doesn't like pulling at low revs - i.e. sub 16/1700 rpm.
OK if you're really toddling along looking for max MPG, but to make good progress you need to keep the rpm pepped up.
ETA...For real world/everyday road driving I wouldn't go back to petrol now, the torque and economy do it for me everytime.
(hope I'm not teaching granny to suck eggs here!)
[Edited on 21/3/10 by nick205]
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roadrunner
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| posted on 21/3/10 at 09:39 PM |
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quote:
Originally posted by nick205
Worth asking the question - are you new to diesels and more so modern diesels?
I went from petrol (205GTI) to a Leon 150 1.9 TDI and it took me a while to gel with it. My current Passat 140 2.0 TDI is the same and really
doesn't like pulling at low revs - i.e. sub 16/1700 rpm.
OK if you're really toddling along looking for max MPG, but to make good progress you need to keep the rpm pepped up.
ETA...For real world/everyday road driving I wouldn't go back to petrol now, the torque and economy do it for me everytime.
(hope I'm not teaching granny to suck eggs here!)
[Edited on 21/3/10 by nick205]
I had a MKIII diesel golf a while back and changed it for a MKIV V5 which was as smooth as a baby's bum. I can understand that it would struggle
at very low revs in higher gears, for me it's just the lumpy accelerating that's not right.
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MikeRJ
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| posted on 21/3/10 at 09:41 PM |
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quote:
Originally posted by roadrunner
By the way, it's the 150 version if that makes
It might do, the PD 150 suffers from soft camshafts which will cause a misfire when the lobes are in an advanced state of wear. I hope that's
not the case in your car but worth knowing.
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roadrunner
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| posted on 21/3/10 at 09:48 PM |
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It's done a very reliable 70k.
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MK9R
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| posted on 21/3/10 at 09:49 PM |
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I just got 115bhp bora which has been remappe to 150bhp. Mine is seems to be running fine and managed to get 57mpg on a 30mile motorway streych of my
commute, that was sitting at 70 and just below. By the time i had done 20 B road miles, not slow but drriving very granny like it dropped to 55mpg. As
a test i drove home the following night at my normal ragging the arse of it pace and it dropped 43mpg and it only saved a few minutes. I have got it
into the low 30's really ragging it. So what you getting mpg wise?
Rough running defo could be to do with maf, unplug the maf and see if car runs better, if it does change the maf.
Get on mk-ivs.net, lots of info on there
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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roadrunner
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| posted on 21/3/10 at 10:11 PM |
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I have just driven about 60 miles from Bakewell to north lincolnshire using the motorways averaging around 80 and only got 36mpg.
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mediabloke
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| posted on 22/3/10 at 01:39 AM |
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Might be the EGR "flap" that's gunked up / stuck, chucking rubbish into the inlet and / or an o-ring missing from one of the pipes
on the turbo. Just got my Octavia back from a garage mate who had a look at it. The combo of the above seemed to have caused me to lose boost and
chuck more fuel than was healthy down the exhaust... 
It ran rough between 1500-2500 rpm with the emissions light on after the intercooler pipe popped open. Even after this was sorted, we cleaned the AFM
with carb cleaner 3 times; each time, it ran nicely for about an hour then back to rough.
Running nice and smooth now, though, with a pleasing 12mpg increase... 
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MK9R
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| posted on 22/3/10 at 07:15 AM |
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quote:
Originally posted by roadrunner
I have just driven about 60 miles from Bakewell to north lincolnshire using the motorways averaging around 80 and only got 36mpg.
That defo ain't right!!! Did 80 all the way to work this morning and got 49mpg. Unplug the MAF and see if car runs better
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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Ivan
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| posted on 22/3/10 at 07:46 AM |
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In South Africa - particularly at high altitudes lugging a diesel in high gears at low revs is a recipe for destroying your turbo - don't do
it.
[Edited on 22/3/10 by Ivan]
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flak monkey
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| posted on 22/3/10 at 07:59 AM |
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The 150 in std form doesnt like to pull in high gears below 1500rpm anyway. They are more laggy than a 130 and dont come on boost until a little
later.
I would suggest changing your driving style and changing down a gear 
Either that or have it remapped, then it will pull from 1100rpm in any gear you like.
The 150 will generally return around 50-54mpg on a-rod driving with average speeds of 50-60mph. Motorway driving will pull that down to around 45mpg.
Sera
http://www.motosera.com
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nick205
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| posted on 22/3/10 at 10:44 AM |
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quote:
Originally posted by roadrunner
quote:
Originally posted by nick205
Worth asking the question - are you new to diesels and more so modern diesels?
I went from petrol (205GTI) to a Leon 150 1.9 TDI and it took me a while to gel with it. My current Passat 140 2.0 TDI is the same and really
doesn't like pulling at low revs - i.e. sub 16/1700 rpm.
OK if you're really toddling along looking for max MPG, but to make good progress you need to keep the rpm pepped up.
ETA...For real world/everyday road driving I wouldn't go back to petrol now, the torque and economy do it for me everytime.
(hope I'm not teaching granny to suck eggs here!)
[Edited on 21/3/10 by nick205]
I had a MKIII diesel golf a while back and changed it for a MKIV V5 which was as smooth as a baby's bum. I can understand that it would struggle
at very low revs in higher gears, for me it's just the lumpy accelerating that's not right.
Does sound like there may be an issue - should be easily checked and identified by a VAG COM read and (competent) technician test drive though.
As to the economy issue, I can only direct you to one of my earlier threads on just that subject 
http://www.locostbuilders.co.uk/viewthread.php?tid=78073
[Edited on 22/3/10 by nick205]
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