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Discussion Starter · #1 ·
Hi all

T5.1 2.0tdi 102ps

Looking for advice/experience regarding a rough idling issue
It started when driving the van cold in Novemeber, just running along at around 1500rpm when the engine spluttered and the revs began surging.
When the engine starts it idles between 800 and 1000 rpm then kangaroos until around 1800rpm with very erratic fueling then smooths out but the engine can still be heard surging when driving along. It does get better when warm but it's chronic when cold.
Tried bosch diagnostic tool and this has revealed no codes on the ECU and there are no engine management lights on the dash?
DPF has been looked at as has the EGR. The fuel rail pressure has been checked and found to be all over the place!!!!
Tried a second hand ECU and took this to Preston VW van center to be coded in to my van. 13/02/15
The van drove away smoothly and i thought the problem was solved until 2 DAYS later and the problem came back as bad as ever.
It's booked in for a VW diagnostic check but i fear this may be a waste of money considering there have been no codes previously.
Does anybody know of, or has experienced these symptoms? I'm scratching my head now!
Would like to hear your thoughts please.
 

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hi, I have exactly the same problem and had mine at the dealers yesterday(2010 2.0tdi 86hp) after 2 hours and being on the diagnostics the result was fuel pressure regulator/fuel rail they are not 100% so therefor when I give them my hard earned £700 it may not solve the problem?????? on the bottom of the report it said test plan could not complete test plan due to vehicle not running correctly??? so they can't find then fault because there is a fault???? so conclusion is vw commercial dealer is not sure!!! they don't even seem to know there own product nor have the skills,knowledge,tools to fix them????
 

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hi, I have exactly the same problem and had mine at the dealers yesterday(2010 2.0tdi 86hp) after 2 hours and being on the diagnostics the result was fuel pressure regulator/fuel rail they are not 100% so therefor when I give them my hard earned £700 it may not solve the problem?????? on the bottom of the report it said test plan could not complete test plan due to vehicle not running correctly??? so they can't find then fault because there is a fault???? so conclusion is vw commercial dealer is not sure!!! they don't even seem to know there own product nor have the skills,knowledge,tools to fix them????
Yeah, thats weird. To complete the pressure regulator test, the engine must be running at idle. But in this case the rpm is fluctuating so the test cannot be performed.

However I don't understand that why the dealer wants to replace the complete fuel rail, when the regulator can be swapped separately. The rail is just a piece of metal, and it comes with the pressure sender and the pressure regulator.

Do you have a detailed quotation from the dealer? I'm curious how much the parts cost there at the UK.
 

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hi,£418 plus vat for fuel rail with regulator, apparently comes as one complete part,vw do not sell a separate fuel pressure regulator!!!! £570 plus vat parts and labour,not guaranteed to solve problem??? unbelievable
 

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hi,£418 plus vat for fuel rail with regulator, apparently comes as one complete part,vw do not sell a separate fuel pressure regulator!!!! £570 plus vat parts and labour,not guaranteed to solve problem??? unbelievable
Don't believe this. There is a separate fuel pressure regulator as I swapped one myself 2 years ago. If my calculation is right it has to be around £275 incl. vat. The part number is 057130764H.

https://becost.ru/vag/img/manufactur/audi/id/013060636

The regulator is no. 8 on the picture, but they try to sell you no. 7.
 

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May be completely wrong but have you checked the clutch switch is working properly? that can cause kangarooing and over reving when changing gear.
 

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Discussion Starter · #7 ·
Thanks for your thoughts people.
I'll mention the fuel pressure switch and clutch switch when it goes in to VW this Wednesday.
I'll write a post as soon as they let me know what they find!
 

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Discussion Starter · #8 ·
hi, I have exactly the same problem and had mine at the dealers yesterday(2010 2.0tdi 86hp) after 2 hours and being on the diagnostics the result was fuel pressure regulator/fuel rail they are not 100% so therefor when I give them my hard earned £700 it may not solve the problem?????? on the bottom of the report it said test plan could not complete test plan due to vehicle not running correctly??? so they can't find then fault because there is a fault???? so conclusion is vw commercial dealer is not sure!!! they don't even seem to know there own product nor have the skills,knowledge,tools to fix them????
Just a quick one,

If the fuel pressure regulator proves to not be the cause then VW can't charge you £700 for a component that you didn't need??
Let me know how you get on please.
Thanks, Phil
 

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it says suspect fault, further checks may be necessary to determine full extent of requirements, hell of a disclaimer. originally they told me there was a hairline crack in the fuel rail and when I told them no that's wrong as its under massive pressure and its not leaking,then they said it was a crack in the fuel regulator???? and the fuel regulator and fuel rail are one part and can not be bought separately !!!
 

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also a quick note,it could be egr valve and if so,some of the 2010-2011 t5's had faulty egr's and vw uk were replacing them under good will baring a small fee for fitting(apparently) check on here as has been mentioned before
 

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Hi all , my 4motion 180 bi di developed similar issues 3 weeks ago , it's been at a diesel specialist in Colchester essex and he's now scratching his head as he's also tried all the above with fuel rail etc , his next move is to check wiring from the ecu i case of a corroded wire etc , I'll keep you posted if there is any developments , sick of hire vans now also !
 

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Has live data for the injectors been checked, could be a leaky injector but still within spec (no fault shown) causing the fuel pressure to fluctuate, the pressure sensor could be reading correctly and fuel pressure is being lost through an injector or not being made or maintained by a faulty lift or high pressure pump
 

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Discussion Starter · #13 ·
Has live data for the injectors been checked, could be a leaky injector but still within spec (no fault shown) causing the fuel pressure to fluctuate, the pressure sensor could be reading correctly and fuel pressure is being lost through an injector or not being made or maintained by a faulty lift or high pressure pump
That's an interesting idea, i've had the injectors and fuel rail inspected but they were not determined to be at fault.
However i'm still convinced it could be mechanical. The van was driving at 1500rpm on a cold morning when it suddenly developed this fault, whatever it may be, it itself at that moment, i'm convinced of that.
The van went in tonight for inspection tomorrow, i'll post my news!
 

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I've put a replacement fuel pressure regulator(second hand with guarantee) and its still the same, phoned the dealers and told them,they said its a process of elimination!!! if I want to book it back in they will put there master technician onto it and he may be able to point me in the right direction ??? honestly
 

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Hi all

T5.1 2.0tdi 102ps

Looking for advice/experience regarding a rough idling issue
It started when driving the van cold in Novemeber, just running along at around 1500rpm when the engine spluttered and the revs began surging.
When the engine starts it idles between 800 and 1000 rpm then kangaroos until around 1800rpm with very erratic fueling then smooths out but the engine can still be heard surging when driving along. It does get better when warm but it's chronic when cold.
Tried bosch diagnostic tool and this has revealed no codes on the ECU and there are no engine management lights on the dash?
DPF has been looked at as has the EGR. The fuel rail pressure has been checked and found to be all over the place!!!!
Tried a second hand ECU and took this to Preston VW van center to be coded in to my van. 13/02/15
The van drove away smoothly and i thought the problem was solved until 2 DAYS later and the problem came back as bad as ever.
It's booked in for a VW diagnostic check but i fear this may be a waste of money considering there have been no codes previously.
Does anybody know of, or has experienced these symptoms? I'm scratching my head now!
Would like to hear your thoughts please.
Just thought I'd share my van issues now it's fixed , it's on a 180 bi-di t5 2010 , driving to work on a cold morning , got 2 miles away and then went into limp mode 4 weeks ago , very rough idling and surging/hunting on tick over with management light on , after garage had plugged in and revealed fuel pressure regulator code he changed the filter and tried the regulator also , it then ended up at a diesel specialist , after a week of trying everything he was about to put it back together and hand it back , he reckoned it may be wiring related and back to the ecu , after a call to the auto electrician to book in I recieved a call with some news , he'd phoned various diesel places up and down the country and a common problem is the IMV valve on the pump , my pressure was fluctuating between 90 to 450 bar , he fitted a used one which he cleaned up and tested and hey presto the van is back to normal ? ,cost me £450 in hire vans , don't know how that got missed on testing but glad to get back to normal working
 

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Discussion Starter · #16 ·
Cheers DMC

I've just read your message and will pass that information on to VW this afternoon.
Litterally just put the phone down to Vw in the last half an hour after them telling me they don't have a clue what the problem could be, and could i come and collect my van.
They said being more than 3 years old they don't wish to get involved as the costs could spiral and they aren't willing to try changing components without me first buying them!?!?! I said it may be 5 years old but it is their current model of T5 and should be of concern to VW and is it common practice for their engineers to just give up on a problem?
Spoke to VW UK and they were very evasive and unwilling to admit never mind share any information on this issue which is obviously known to some of their dealerships.
I'll try the IMV and let you know my findings ASAP.
Thanks again for everybody's invaluable experience!
 

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--------------------------------------------------------------------------------

hi,just an update,I have getting mine sorted now,when I replaced the fuel pressure regulator I actually changed the fuel sensor thinking it was the regulator and that is what the problem was,it is almost impossible to take off without taking the fuel rail off, just for anyone who needs to know when people are selling used regulators on fleebay most of them are pictures of the pressure sensor and not the regulator. the regulator is the one on the n/s, not the one on the left hand side when looking from under the bonnet.
good luck
 

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Discussion Starter · #18 ·
Cheers Bigegg

Van currently sat at the diesel specialists and should know the outcome soon regarding the fuel pressure regulator. Will post my news!

Thanks for your correspondence.
 

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Discussion Starter · #19 ·
Just a final note to any readers of this post.
Finally fixed after replacing the suggested fuel pump valve and fuel rail valve earlier in this post.
Thanks greatly for the advice and experience of fellow readers.
If anybody reading this needs any help i'd gladly pass on my information so they hopefully won't have to experience the levels of frustration i had to go through. Email for info: [email protected]
 

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Just a final note to any readers of this post.
Finally fixed after replacing the suggested fuel pump valve and fuel rail valve earlier in this post.
Thanks greatly for the advice and experience of fellow readers.
If anybody reading this needs any help i'd gladly pass on my information so they hopefully won't have to experience the levels of frustration i had to go through. Email for info: [email protected]
Glad your back up and running , hopefully the info on the pump valve helped narrow it down , all the best Darren
 
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