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VW Transporter 2.0 TTDi 2010 - Lumpy idle and bad hesitation when cold, code 5175 #

Posted by Kristopher Sheridan on January 24, 2014, 9:32 pm

Year of Manufacture *: 2010
Engine Size and Code *: 2.0 ttdi
( Optional ) Scanner Used: VCDS
( Optional) Fault Codes: 5175 - Fuel pressure regulation

Hi all, First post here so bare with me..

I have in the workshop currently a 2010 vw transporter 2.0 twin turbo diesel, Customer complaining of lumpy idle and real bad hesitation when cold, once warm, it drives superb, however when back on idle its still lumpy!

When cold, under hard acceleration, hesitation is terrible with fuel pressure fluctuating between 600 bar and 1200 bar, once we get some tempreture into the engine, it'll pull nice and smooth with stable fuel pressures around 1500-1600 bar

Codes extracted with VCDS - 5175 - Fuel pressure regulation,

have checked injector back leak as live data showing erratic pressure sensor reading, All ok, Scoped FRP sensor, Full 5v ref and good earth, Voltage on sig wire fluctuating between 0.8V and 1.3V, (approx 100 bar and 370 bar)

Have ran out of time on this tonight but hoping to have a look deeper tomorrow when engine is cold, will scope IMV and relief valve on rail next..

have also taken a fuel sample and it seems ok...

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Ian Baxter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1560' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 12:43 am, in reply to "2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Ian Baxter

Hello Kristopher,
What's the mileage and what's the service history as this could be caused by something as simple as a partially blocked fuel filter

Ian

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 10:53 am, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Mark Carter

What system is it running?

Mark

Modern cars, Its all wizardry and witchcraft

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Kris sheridan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 6:43 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Kristopher Sheridan

Ian, full history and just had full service by garage thinking it would cure it!

109k on clock,

Mark, can't remember, sure its Bosch but will double check on Monday, not had chance to look at vehicle today its definitely got 2 point control..

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 8:23 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Mark Carter

If its CP4 you may be able to get it to work off single point control to help pin point the fault.

Mark

Modern cars, Its all wizardry and witchcraft

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Kris sheridank <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 10:29 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Kristopher Sheridan

It won't run as single point control, I thought about that too.

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on January 25, 2014, 11:02 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"

Which one are you disconnecting, the ZME or the DRV?
It will not run if you disconnect the DRV but it may if you disconnect the ZME depending on the control strategy of the system.

Mark

Modern cars, Its all wizardry and witchcraft

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Kris sheridan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on January 26, 2014, 11:14 am, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Kristopher Sheridan

I'm guessing now.. By zme you mean the inlet metering valve and DRV the control on the rail?

I disconnected the control on the rail and it wouldn't Run...

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on January 26, 2014, 1:12 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"

Yes I am, and no it won't (it will drop rail pressure with that one disconnected)

But if you have a "standard" ZME fitted it should default open with the ECU flagging a fault for it but at the same time controlling the pressure via the DRV.

It will all depend on the control strategy that the ECU is programmed with.

Mark

Modern cars, Its all wizardry and witchcraft

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Kris Sheridan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on February 3, 2014, 8:47 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Kristopher Sheridan

Bit of an update on this...

if i disconnect the "ZME" valve the vehicle still starts and runs with no change to the way it behaves, although it does flag a fault code and the glow plug light flashes..

I have scoped the "ZME" feed we can see a clean duty cycle (matches what i can see in live data as a %) However the ZME doesnt seem to be responding to the change in duty cycle when you opperate the accelerator pedal..

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on February 3, 2014, 8:55 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Mark Carter

>>> the vehicle still starts and runs with no change to the way it behaves,<<<

Are you saying that with the ZME disconnected it still runs like a sack of shite?

If so, what is the duty cycle of the DRV doing whilst this is going on?

Mark

Modern cars, Its all wizardry and witchcraft

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Kris Sheridan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on February 3, 2014, 9:12 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Kristopher Sheridan

Yes, Still runs erratically!

didn't capture duty cycle at the drv very well as i was using my handheld scope, but from what i could see, when the engine revs were dropping the DRv duty cycle would reduce, and then as the revs picked up the duty cycle would increase...

would i be right in saying the ECU appears to be trying to control the fuel pressure via the DRV as it is seeing an issue with the ZME?

Regards
Kris

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on February 4, 2014, 11:11 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Mark Carter

>>> would i be right in saying the ECU appears to be trying to control the fuel pressure via the DRV as it is seeing an issue with the ZME? <<<

That's what it should do, but if the fault is still present we have to look further.

So we are saying that at idle with the ZME disconnected the engine speed is surging and the rail pressure is following suit?

That's starting to sound like a DRV issue.

If so what is the supply pressure doing at the same time?

Mark

Modern cars, Its all wizardry and witchcraft

Re: VW Transporter 2.0 TTDi 2010 - Lumpy idle and bad hesitation when cold, code 5175 #

Posted by Milan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat5374' width='330' height='300' border=0 style='border:none;'> on February 7, 2014, 9:30 pm, in reply to "VW Transporter 2.0 TTDi 2010 - Lumpy idle and bad hesitation when cold, code 5175 #"
Milan Lazarevic

Hi Kristopher, there is a technical bulletin relating to issues similar to what you describe, the bulletin states: -
To check for swarf in the high-pressure pump the valve for fuel metering N290 (IMV), contrary to the repair manual, may be removed.
When removing the valve for fuel metering N290 observe the following points:

When removing the fuel metering valve the high pressure pump can also damaged by dirt from outside.
• Before removing the N290 carefully and thoroughly clean the surrounding area.
• If there is no swarf on the N290 or in the hole, refit the valve straight away. Check both O rings. If they are damaged, replace the high pressure pump.
• When fitting the N290 apply fuel or oil on the lower O ring.
• Push in the N290 by turning it slightly.
• Tighten both M5 bolts by hand - do not lubricate the thread.
• Pre-tighten with 2 Nm and then to 6.5 – 7 Nm.
If there is a swarf accumulation, the complete high pressure fuel system must be replaced:
- Replace high pressure pump, pressure control valve, rail, injectors with high-pressure pipes, fuel pressure sender and overflow oil pipe with bleeder valve
In the low pressure fuel system the fuel pump in the tank, the fuel filter and the electric fuel pump must be replaced.
Clean or flush out fuel tank and fuel supply and return pipes (low pressure) between high pressure pump/rail and tank. A replacement is not necessary.
- Suck out the tank before changing the fuel pump and flush out the fuel pipes.
- After removing the fuel pump wipe the tank floor as far as possible with a fluff-free cloth.
BUT
From experience I have found the IMV is often the fault on these, the valve is not available separately from VW - a new H.P pump is required,
I believe these are available separately from some diesel specialists now.
Check the ability of the low pressure side to maintain it's specified pressure - 4.5 Bar is the specified value, you may see it flicking up to 6 bar at idle. Raising the idle speed will even the fluctuations out & give you a steady reading at the specified 4.5 bar if the low pressure side is okay,
Scope the rail pressure sensor - if the IMV is sticking due to swarf or a failing IMV valve you should see the rail pressure bouncing as it tries to control the pressure in the rail against the IMV issues.

I notice you are using VCDS, on the dealer tool there is a basic setting that resets the high pressure regulation & can provide a temporary fix to the poor running if the HP pump is starting to fail - It may be worth a look to see if VCDS can base set this system?

Milan

Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold

Posted by Michael Whitworth <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5568' width='330' height='300' border=0 style='border:none;'> on February 9, 2014, 10:53 pm, in reply to "Re: 2010 T5 transporter TTDi - Lumpy idle and bad hesitation when cold"
Mike Whitworth - Administrator

Hi Mark,

This sounds very similar to the one we spoke about.

Kristopher,

Marks knowledge on this system is Excellent, He should be able to guide you to a solution.

Mike

M.O.M. Miserable Old Manc

Re: VW Transporter 2.0 TTDi 2010 - Lumpy idle and bad hesitation when cold, code 5175 #

Posted by Kristopher Sheridan <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3659' width='330' height='300' border=0 style='border:none;'> on February 28, 2014, 9:53 am, in reply to "Re: VW Transporter 2.0 TTDi 2010 - Lumpy idle and bad hesitation when cold, code 5175 #"
Kristopher Sheridan

OK, i know a little late but this vehicle has been back with the customer for a good few weeks now and is A-ok!

After doing some research on this specific diesel system and using some very helpful comments on this thread, we carried out some tests to eliminate certain components, What we found was that the pump was unable to build maximum pressure unless the you pick up the engine to about 1500RPM.

with the IMV disconnected on the pump, and the valve on the rail shorted to ground at idle we only seen 800bar before the engine cut out!

Pump was removed by my customer and sent for test (?!) and repair / replacement.

Still have not spoke to the garage to ask in detail what was done but the company sent back a new pump and the vehicle is running perfect!

when i have time to speak to them in detail i will post results..

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