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2.5 tdi lack of power

Printed From: The Brick-yard
Category: T4 Section.
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URL: http://www.brick-yard.co.uk/forum/forum_posts.asp?TID=90697
Printed Date: 23 Apr 24 at 08:47
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Topic: 2.5 tdi lack of power
Posted By: Eddy Dar
Subject: 2.5 tdi lack of power
Date Posted: 24 Nov 15 at 12:00
Hi All,

I've posted this in the LT2 Section as well but as its about the engine & technical thought I would ask the T4 experts if they've had similar problems. 

I have a power issue with a van we have recently bought, vw lt 2.5 tdi with 200k on it, it seems gutless on a hill and doesnt have the kick or punch my other vans have. On the flat seems okay.

It starts off the key straight away, its doesnt smoke and the turbo does kick in but its delayed. Foot flat to the floor constantly but it doesnt fly.

To date I have actioned the following:

Because I have 5 other vans (LT35/46) 2.5 tdi's I have actioned the following:

1. Swapped MAF/AFM & MAP (Put VAGCOM on cleared codes MAF came up, N75 valve, and injector 4 Needle fault and immobiliser fault ) Cleared codes none came back up so assume they were there before. Which confirms no wiring faults either.
2. Changed boost soleniod pack on bulk head (all of them)
3. Checked Vacuum Pipework to ensure nothing is fitted in the wrong place/wired wrong.
4. Changed Intercooler, checked pipework.
5. Rear Brakes stripped, handbrake mech was binding, calipers were sticking to fitted news pads (whoppie thought we had cracked it) better but still more or less the same. Did the test after a drive throw bucket of cold water on ALL wheels and no fizzle or steam as we orIginally got on the back nsr wheel. 
6. Changed Turbo better again but still delayed turbo response.
7. New to VAGCOM so not 100% sure how to check pump timing, but I've always done these by hand n the past with no problems.

I'm wondering if its a worn engine but being diesel you don't get the wear as you do with petrol engines. So hence the reason why I on here to ask you guys.


Replies:
Posted By: donecan
Date Posted: 24 Nov 15 at 15:37
Being that my knowledge is limited, you've already ticked off every single thing I would have looked at...hopefully someone else on here can help!

Posted By: ELVIS
Date Posted: 24 Nov 15 at 17:17
Have you driven with MAF unplugged? No fault codes with no power points towards MAF. Was it an OE replacement unit?
If you have VCDS/VAGCOM you can also look at MAF - actual v specified.

All inlet tract ok? Turbo pipes etc all ok?

-------------
Www.justgiving.com/ELVIS-SUMMERS

Posted By: Eddy Dar
Date Posted: 25 Nov 15 at 08:33
No, as explained I have other 2.5 tdi vans with no problems, so i just simply swapped the parts over. 

No I have never driven without the MAF unplugged. It may have been disconnected at some stage by the previous owner, all I got out of him was as a last resort he has had injectors tested with no problems.

Posted By: Eddy Dar
Date Posted: 27 Nov 15 at 12:14
Hi All,

Just an update, put VAGCOM on and re-checked timing all was ok. 

Butttttt the fuel temperature was up at 140 and VAGCOm was saying its too high. What would cause this ? 

The temperature gauge for the coolant was just below 110. 

Posted By: ob1
Date Posted: 28 Nov 15 at 10:37
I reckon I'd be looking at the fuel filter? They have a recirculation valve when the engines cold i think? someone will know more than me?

Posted By: Daztwigg
Date Posted: 28 Nov 15 at 18:10
Maybe faulty fuel temp sensor in the top of the pump

Posted By: Eddy Dar
Date Posted: 30 Nov 15 at 11:30
Hi,

Yes put VAGCOM on and now it says ECT not warm enough ?? The Coolant gauge on the dash shows the needle is sitting around 8 pm which is around 85 degrees C

The fuel temperature is sitting around 143 

The van is frustratingly slow and hs no power up hill.

I'm going to change the fuel filter next see how that goes.

Posted By: Mikey Video
Date Posted: 03 Feb 16 at 21:24
Sorry I'm not writing with answers but I am suffering with the exact same issue in my recently bought van so I'm watching with interest.
One bit of advice I've had, not covered here is to check the Catalytic converter as this sometimes gets replaced with a bypass pipe, when it's changed back, crud in the cat blocks it.
I'm no mechanic but worth a look?

Posted By: vinylritchie
Date Posted: 27 Apr 16 at 11:36
I'm also having exactly the same issues with my T4 2.5TDi.  I'm only just starting out with mine and don't yet have the mechanical know how.  But trying to build up my knowledge.  Let us know how you are getting on.

Cheers

Posted By: Mikey Video
Date Posted: 28 Apr 16 at 00:16
Hi. Yeah, timing was way out vinylritchie. Running much better now. Intending to blank the EGR next which apparently has good results. Will let you know how I get on!

Posted By: vinylritchie
Date Posted: 02 May 16 at 22:14
How did you resolve your issue?

Posted By: Mikey Video
Date Posted: 03 May 16 at 10:59
Took my van to a local mechy recommended to me. Not much of a spanner monkey myself. Sorry I can't be more helpful.

Posted By: vinylritchie
Date Posted: 06 May 16 at 16:04
No problem.


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