Undiagnosed Fault 1.4 TDI

Nomind

Member
Hi guys

I am a new member. My wife and I have owned a 2005 1.4 TDI Special Edition since 2008 and have not had any problems with it until now.

About 3 weeks ago, my wife experienced a sudden loss of power whilst driving at about 70mph on a. Motorway and the engine stopped running soon after. Luckily she was able to pull up to the hard shoulder before the engine stopped. The engine did not restart until after about 10 mins by which time she had called the breakdown service. The service guys plugged in their diagnostic computer when they arrived but no fault was revealed. Both my wife and the service guy however thought there was some burning smell - like rubber. The service guy suggested that the clutch may have burned. My wife was however able to drive the car back home gingerly - about 25 miles.

I took the car to our guy - who has been doing all the service and repairs all these years - but his diagnostic equipment also did not reveal any faults. He suggested that the problem may have been caused by ‘dodgy fuel’.

We continued to use the car for another 2 weeks or so. It was however clear that it was not running well. We kept our speed below 50mph. The car always seemed to be struggling when going uphill.

I noticed that it was struggling particularly badly on the motorway last Sunday night. It was a very cold night. The struggle was bad when going uphill. I was unable to go beyond 25 - 30 mph and I had to pull up in the hard shoulder when it became clear that the car would not make it up the hill we were on. The engine would not start after I turned it off until after about 12 mins. We called the breakdown service again and again they plugged their computer. This time, it picked up a fault - coolant temperature sensor. Unfortunately, the chap accidentally cleared the fault. We were subsequently able to drive the car for another 10 miles or so after (not being able to go beyond 20mph) to get to a safe place from which we were towed back home.

I have been back again to my guy who has carried out a comprehensive diagnostic check using his computer. Again the system has not revealed any fault. He is firmly of the view that the coolant temperature sensor cannot be the cause of the problem. He suspects the fuel pump and/or fuel filter but cannot guarantee that the problem would be over after we spend the money.

Has anyone experienced this fault before? Does anyone know for sure what has gone wrong? We need help please.
 
Hello Nomind and welcome, albeit it would have been nice if your first post wasn't because of a fault.

It's hard to say from here, but my money is on fuel starvation - it would tie in with the engine stumbling at higher speeds/demands and also needing a bit of time to start again after a cut out. Has your servicing chap ever done the fuel filter? It's possibly the original factory one that's there if not. Now the danger of changing the fuel filter on later models is that the small central bolt has a tendency to shear off and a full new housing is then required and they were around £70 when I last priced one up.

Also, a fuel filter issue wouldn't generate a fault code. I also doubt that a coolant temperature sensor would be the issue. There was a recall on the diesel fuel pumps too from certain VIN range. The details are here:

http://www.dft.gov.uk/vosa/apps/rec...AB953713DA80256F6B003E9848&freeText=Blank&tx=

Hope you get a fix and when you do, please let us know so we can expand the knowledge-base.
 
Many thanks Skipton01. I’m sorry my very first post was to report a fault.

Your advice is appreciated - I will pass it on to my chap. I would be happy if it was just the fuel filter - I have been informed that a new fuel pump plus filter would cost £508 excluding labour. Thank you also for the info about the recall. I will check it out.

I will of course come back to let you know how I get on with the fault.
 
I too would change the fuel filter and if the temp sensor came up I'd change it anyway it's a 7 pound part.

Sent from my SM-J510FN using Tapatalk
 
Many thanks Skipton01. I’m sorry my very first post was to report a fault.

Your advice is appreciated - I will pass it on to my chap. I would be happy if it was just the fuel filter - I have been informed that a new fuel pump plus filter would cost £508 excluding labour. Thank you also for the info about the recall. I will check it out.

I will of course come back to let you know how I get on with the fault.

There's no need to apologise - I merely meant that it's a shame that you've had to post due to the fault that's all. I can't see a reason why the pump would need replacing - a typical failure would result in fuel leaking into the engine bay (no risk of fire though with diesel) if it were the pump. I'd get the filter done though as a matter of course and the coolant sensor is a fairly easy swap with a cold engine as long as you're quick - there'll be little loss of coolant either.

Fingers crossed that you'll have it fixed for less than £25 plus labour.
 
Fuel filter was my first thought. Remember the little screw is plastic - finger tight plus a tweak only otherwise it's a new filter housing!
 
Fuel filter was my first thought. Remember the little screw is plastic - finger tight plus a tweak only otherwise it's a new filter housing!

That'll work for replacement but undoing the screw could be where it gets messy - if it's not budged in 12 years, it may well break in a perfectly innocent attempt to undo it and if it does, you'd better have your hose clamps fitted tightly!!

It may be wise to get a new housing in any case - chances are it'll be needed.
 
That'll work for replacement but undoing the screw could be where it gets messy - if it's not budged in 12 years, it may well break in a perfectly innocent attempt to undo it and if it does, you'd better have your hose clamps fitted tightly!!

It may be wise to get a new housing in any case - chances are it'll be needed.

Maybe but it's a plastic screw in a plastic housing, no reason for it to seize and not much reason to spend £75-ish upfront on a housing you don't need.
 
Maybe but it's a plastic screw in a plastic housing, no reason for it to seize and not much reason to spend £75-ish upfront on a housing you don't need.

Agreed - it's a lot of money to spend up front, but if only it was a case of plastic screw in plastic housing and there being no reason for it to seize. I've come across so many of the little blighters which do snap because they become brittle over time being in contact with diesel and then there's the build up of stiction to over come - 12 years with possibly no shield over it is a long time for a little plastic screw to endure.

EDIT

There was at one point, talk of producing a metal version of the screw which would have negated the requirement for an entirely new housing in the event of it snapping - did this ever come about??
 
Last edited:
For anyone who cares, this is what lives in the fuel filter after 55,000 miles !

2017-12-16 10.06.55s.jpg

Not nice, last time it was just dirty black water, this time is more like pond slime. However, as water will collect in the bottom of the filter and bacteria can live in that water, this is to be expected.
 
Bloody amazing really - life! Who'd want to live in stagnant water covered in mucky diesel? I presume the screw came out without incident.
 
I suppose though really, it's not actually necessary to remove the little screw at all - as long as you've a large container underneath, you can just undo the main cap on the housing. Yes, the diesel in the filter will all spew out at once, as opposed a controlled and steady trickle from the drain hole screw, but at least there's no danger of breaking the screw.
 
I suppose though really, it's not actually necessary to remove the little screw at all - as long as you've a large container underneath, you can just undo the main cap on the housing. Yes, the diesel in the filter will all spew out at once, as opposed a controlled and steady trickle from the drain hole screw, but at least there's no danger of breaking the screw.

Been thinking exactly the same; why touch the drainplug?
 
I suppose though really, it's not actually necessary to remove the little screw at all - as long as you've a large container underneath, you can just undo the main cap on the housing. Yes, the diesel in the filter will all spew out at once, as opposed a controlled and steady trickle from the drain hole screw, but at least there's no danger of breaking the screw.

Unfortunately not, I thought about that, but the lip of the drain plug blocks access to the 36mm hex head of the main cap housing. Unless of course if you manage to use the two lumps that stick out of the cap to turn it - if you can find a suitable tool.
 
Unfortunately not, I thought about that, but the lip of the drain plug blocks access to the 36mm hex head of the main cap housing. Unless of course if you manage to use the two lumps that stick out of the cap to turn it - if you can find a suitable tool.

NOT removing the drain plug is an excellent suggestion but you have a good point. Would some kind of right angle spanner work on the big hex?
Thinking of plumber's basin wrenches, such as this, second picture,

https://www.toolstop.co.uk/index.ph...vkVdAbOvKb_JOqveCXBrE-sou8nSUHIxoCtMkQAvD_BwE

Andy

PS Just Googled and found what are called crows foot scanners.This one looks the job

https://www.tools-giant.com/item.ph...aZ0tZN7aeKOblV_uY2b_VlDB46e3ROkhoCGYMQAvD_BwE
 
Last edited:
That looks like diesel bug, it is very hard to get rid once in the fuel system, if left uncheck it can strain the fuel filter. This week in work i had to strip down the fuel tank /system, etc on two military sv man trucks because of this.

https://www.crownoilenvironmental.c...4073911334&target=&placement=&device=c&adtype[adtype]adposition=1t3&campaignid=326911974&adgroupid=28418734854&gclid=EAIaIQobChMI3KeW8cmQ2AIVw7ztCh0rNw76EAAYAyAAEgIr6fD_BwE

Be very very careful using anything other than a six sided socket on the plastic nut. Even a 12 point socket can shatter the ABS housing due to point force and remember the ABS will be more brittle than when new especially in these cold temperatures
I get why you are trying to do so but it is a bad idea
I will try in the new year to get an aluminium screw available just need an example to copy
Cheers


Sent from my iPhone using Tapatalk
 
Be very very careful using anything other than a six sided socket on the plastic nut. Even a 12 point socket can shatter the ABS housing due to point force and remember the ABS will be more brittle than when new especially in these cold temperatures
I get why you are trying to do so but it is a bad idea
I will try in the new year to get an aluminium screw available just need an example to copy
Cheers


Sent from my iPhone using Tapatalk

Agreed, the cap of the filter housing is surprisingly tight. Anyway, I have an old broken screw I can send you if you want. Just let me know.
 
Back
Top