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VW Transporter T5 2.5 PD TDi 2005 - Loss of power #

Posted by Peter Holland on October 16, 2014, 5:01 pm

Year of Manufacture *: 2005
Engine Size and Code *: 2500 PD
( Optional ) Scanner Used: Vag Com

This guy has just bought this Van off of the internet from Ireland. It never even made it out of the docks and had to be recovered here. What's that rule about never buy a vehicle unseen? Further investigation has revealed that the engine has recently been apart and very badly reassembled.

Basically, it is very reluctant to rev up, it takes ages to respond to the throttle and has no power whatsoever.

Vag Com has not given us any clues, no fault codes and live data as far as I can discern is ok.

We have checked -

Exhaust back pressure

EGR valve operation

Turbo actuator operation, both manually and under the control of the ECU.

Turbo boost pressure - a maximum of 0.2 bar seen under full throttle.

Turbo pipes, intercooler etc all examined and checked for air leaks.

MAF sensor - I haven't replaced this but we do see a maximum reading of 4 volts when rev'd hard. This does seem a little low but the engine is just not doing any work so I assume this will account for the low airflow.

I'm beginning to wonder if this could be a Cam timing issue, although I would have thought this would have logged a code. I have scoped the cam and crank signals but I don't have anything to compare them with.

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Fiachra Purcell <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3006' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 9:26 am, in reply to "VW Transporter T5 2.5 PD TDi loss of power"
Fiachra Purcell

Hi Peter.
I don't have a comparison.
I do however know that these PD engines (BPC, AXD) will not start when they're 1 tooth out unless the cam sensor is disconnected.
Have a look at the physical cam timing as it is not locked to the pulley (floating pulley like focus cranks).
You will need the special tools to check timing on these.
Regards.
Fiachra

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Peter Holland <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 1:01 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Peter Holland

Hi Fiachra,

I'm not familiar with these engines, does the cam sensor pick up off of the cam wheel? If the cam wheel is not locked to the shaft I take it that in theory the cam wheel timing could be correct but the shaft could be timed incorrectly? So, as far as the ECU is concerned the timing in correct hence no fault codes?

I've spoken to another garage locally that also have one of these T5s in with the exact same fault. Both these vehicles have just had engine rebuilds....

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Fiachra Purcell <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3006' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 1:56 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Fiachra Purcell

Hi Peter.
The sensor pick up is on the cam wheel.
Yes the ECU assumes timing is correct if the pulleys are correct.
The camshaft itself could be in any position.
The tools are required to time these properly.
It's not that hard to check. Two blanking plugs at the front of the engine and remove one of the engine mount bolts.
regards.
Fiachra

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 2:11 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Mark Carter

Whats your AMM reading at idle without EGR

Modern cars, Its all wizardry and witchcraft

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Peter Holland <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 3:07 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Peter Holland

MAF at idle = 300mg/st or 2 volts.

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 17, 2014, 8:51 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Mark Carter

Well that is telling a story by its self.

Have you looked into why its so low?

Mark

Modern cars, Its all wizardry and witchcraft

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Peter Holland <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5256' width='330' height='300' border=0 style='border:none;'> on October 20, 2014, 9:20 am, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"

Hi Mark,

Yes I have, it has me stumped at the moment hence my post on here.

I'd put the low readings down to the fact that the engine simply isn't doing any work. The problem is I can't get to the bottom of why it isn't.

Looking at the fault logically, why won't the engine rev?

1 - No boost pressure? It does have some boost pressure, I see about 0.2 bar when rev'd hard. It passes the turbo test on Vag Com

2 - EGR stuck open. Tested with both VAG Com and manually opening and closing the actuator with a vacuum to confirm that it is working correctly.

3 - Exhaust blocked - I've disconnected it from the turbo, still no different.

4- MAF too low - well, it is but is this down to an engine fault. I'm sure we've all been there and jumped to the conclusion that the MAF sensor is faulty due to low readings which then turns out to be another underlying fault. I don't have any live data from one of these engines to compare it with. I do see a maximum of 4 volts when rev'd to 4000 RPM.

5- A fuelling issue - pump pressure too low? I've yet to test this.

6- A timing issue. No fault codes stored to confirm this but there is a possibility that the cam itself could be timed wrong but the cam wheel is right. ECU would assume all is ok. I haven't checked this yet.

7 - The engine has been apart which would lead me to suspect that this is likely to be a mechanical issue. Assumptions though are the mother of all cock ups!

My experience with the PD engines has shown that they are a pain to diagnose these sort of faults as the ECU has no fuelling feed back, either on the high pressure side or injector compensations. I'm going to check the pressures at the pump later when I have a moment.

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 20, 2014, 10:48 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Mark Carter

>>> as the ECU has no fuelling feed back <<<

Oh yes it does (or at least it should have from memory)

Give me a call if you think a bit of head banging will help.

Mark

Modern cars, Its all wizardry and witchcraft

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Kevin Apps <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on October 21, 2014, 1:14 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"

Peter

"I've spoken to another garage locally that also have one of these T5s in with the exact same fault. Both these vehicles have just had engine rebuilds"

Do you have the tools to do this rebuild ? if not price up the cost of the tools and you may see a reason why it's not been put back together correctly.

I have seen the cam timing wheel come loose from the cam gear on these as well.

Kev.

Re: VW Transporter T5 2.5 PD TDi loss of power

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 29, 2014, 6:48 pm, in reply to "Re: VW Transporter T5 2.5 PD TDi loss of power"
Mark Carter

Did you ever get to the bottom of this issue?

Modern cars, Its all wizardry and witchcraft

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