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Diesel help
roadrunner - 7/8/10 at 09:45 AM

Hi guys.
I have had an on going problem with my Bora 150 tdi that i have been trying to solve with no avail.
I have a judder when the engine is under load, it is more noticeable the higher the gear and when more is asked of the engine say in sixth and going up hill. Now the judder doesnt start until 1400 revs just as the turbo starts to spool up and it stops at 2500 revs, it is the same in every gear except 1st and 2nd. Other problems that might be associated with it are lack of fuel economy ,im only getting 35 - 40 out of it, smoke is not excessive by the way, and every now and then the turbo trips out but is fine on the restart.
One thing that i have noticed is when the turbo trips there is no juddering at all even when trying to accelerate, when the turbo is working you can just feel the judder even when at a steady speed.
Now things i have done.
I have replaced the cam as old one was worn.
I have replaced the MAF sensor.
Cleaned out the EGR but dont know if it still works.
I have tried to clean out the turbo as it is a VNT type, this did make a small difference as the main boost came in at a different rev range. Also the N75 valve was checked and seemed to be working ok.
I was starting think it was the flywheel as VWs are known for this , but after the turbo issues i am swaying more towards that.
Is it worth stripping down the turbo and giving it a really good clean.
Thanks for looking.
Brad.

[Edited on 7/8/10 by roadrunner]


PSpirine - 7/8/10 at 09:50 AM

Not meaning to insult your intelligence if you've already done this, but..

Step 1 - replace your diesel filter (I don't know if the VAG tdi's have one or two of them).

Step 2 - make sure you don't have any air leaks in the system. This may or may not apply to the VAG tdi's as they may well have a lift pump in the tank?

Sorted all my similar problems (albeit on another engine).

Pavs


graememk - 7/8/10 at 09:56 AM

has it ever been remaped, or does it have a bodge box on it.?

FPS would cause this and a remap or bodge box also "adjust" the redings from the FPS to the ECU


roadrunner - 7/8/10 at 10:15 AM

I have replaced the filter and checked for air leaks.
As for being remapped, this has crossed my mind too. If this is the cause would it be possible to fix with another remap.


graememk - 7/8/10 at 10:17 AM

follow it up the road, if its been mapped or bodge boxed they normally smoke alot more than normal


MakeEverything - 7/8/10 at 10:26 AM

dual mass flywheel problem?

Sounds like something is out of balance.


Strontium Dog - 7/8/10 at 10:45 AM

As above if it has a dual mass flywheel it could be that. I once had an Omega (I know, but it was ever so cheap) that had a hydraulic engine mount/stabiliser. It failed and the thing felt like a vibrating roller. Might be worth a look to see if it has anything similar!


mangogrooveworkshop - 7/8/10 at 11:12 AM

engine mount ok?


roadrunner - 7/8/10 at 11:55 AM

quote:
Originally posted by MakeEverything
dual mass flywheel problem?

Sounds like something is out of balance.

If it was the flywheel it would judder throughout all the rev range and when the turbo had tripped. I think.


roadrunner - 7/8/10 at 11:56 AM

quote:
Originally posted by mangogrooveworkshop
engine mount ok?

Is there a way of checking engine mounts.


woolly - 7/8/10 at 12:33 PM

having just spent to much time on a Laguna with a hesitation but bring on the inj fault light under load. found a slight split in the intercooler. now fixed.


luke_stephenson - 7/8/10 at 12:33 PM

If it was the flywheel im sure the vibration would be more prevelant in a certain rev range when it reached its resonant frequency. i think anyway.

just a quick question, what do you mean by the turbo tripping? ive never heard of this before?


roadrunner - 7/8/10 at 12:42 PM

quote:
Originally posted by luke_stephenson
If it was the flywheel im sure the vibration would be more prevelant in a certain rev range when it reached its resonant frequency. i think anyway.

just a quick question, what do you mean by the turbo tripping? ive never heard of this before?

It can happen when the ECU thinks the car is over boosting, so it goes into limp home mode, just a flat diesel with no turbo. If you find a quite spot with no traffic i can dip the clutch switch the ignition off then on again and hey presto the turbo is back on.


Ninehigh - 7/8/10 at 01:45 PM

quote:
Originally posted by roadrunner
If you find a quite spot with no traffic i can dip the clutch switch the ignition off then on again and hey presto the turbo is back on.


I just find a straight bit, then flick the ignition off and on. It then bump starts itself


Stott - 7/8/10 at 05:06 PM

It will be the DMF I reckon. Mine does it, so do millions of other VWs. It only happens when you're really labouring it in a gear that strictly speaking is a bit high for the situation IMHO.

Mine also got worse when I put uprated lower arm bushes on and the juddering got more pronounced.

Max torque on them is something like 1800-2400 isn't it? which is where the problem will show then a combination of the torque dropping off, and speed rising to mean the gear is now easily pullable, mean you can't feel it after that.

Mine is on 121k and has done this from about 97k ish, you just learn to drive around it. My other one of these cars didn't do it (new) and my dads mrs one doesn't do it yet (50k on it)

As for the fuel economy, if you watch the mfa if the car has one, anything around max torque is a bad place to be for high mpg, they tend to like it a bit over 2.5k if the road is undulating at all, if you're on the dead flat for a bit cruising at about 1800 rpm works, but as soon as you get to a little bit of a hill and the turbo has to spool you're better off changing down

all IMHO

HTH
Stott

EDIT : forgot to add I had the clutch out at 106k to check it and the dmf was worn but inside the limits Sachs publish so I put it back in, although it was noticably sloppier than a new one.

[Edited on 7/8/10 by Stott]


roadrunner - 7/8/10 at 09:06 PM

I have also noticed that my clutch peddle sticks every now and then, dont now why.


roadrunner - 24/10/10 at 07:27 PM

Just to let everyone know that i have replaced my DMF and that's sorted my problems.
I have spent hours trawling through diesel forums looking at threads with people having the same problems, only to find that the thread is never finished and no answer found. So I no it's late, but at least if anyone comes across this thread they will now what to do.
Thanks again
Brad.