Hi all

Got a '57 plate Scout 2.0 TDI which has 40k on the clock. I have had it since new but since around 30k I have been having problems with what I can only describe as a misfire.

It's reasonably consistent in that it happens at exactly 1800 rpm and again at 2200 rpm. It isn't noticable in 4th-6th gear however, if I drive on flat smooth (horizontal) tarmac in any of these 3 gears keeping the revs between 1800 and 2200 rpm it feels 'lumpy'.

In 1st to 3rd, when it misses it's a pretty solid miss which feels like the car is about to stall. Not particularly convenient when pulling out of a junction however, now I'm used to it I tend to floor the pedal and keep going. The instinctive reaction is to take your foot off the gas which, with traffic approaching from the side could be nasty. It seems to have lessened considerably since the outside temperature has dropped below 7 degrees Celsius.

I have tried injector cleaner and the car has had all new glo-plugs. It has never been mis-fuelled however you never know what you're getting at the pumps these days!

I have taken the car to 2 different dealerships, both of which thought I was nuts, put the car on the tester and proceeded to tell me there was nothing wrong with it.

I'm at a complete loss now as to what to do...apart from put up with it for another 12 months until I change the car again.

Any thoughts are much appreciated.

Mike

I wonder if you have a cracked head?

Wouldn't that cause symptoms right through the rev range? You'd also expect it to get worse at higher revs???

I was wondering how many sets of injectors they have...I know petrol engines have idle and main jets but don't know anything about diesels.

I wonder if you have a cracked head?

http://briskoda.net/forums/topic/146558-2-years-of-bad-starting-cured-by/

Mike, just in case it's the throttle potentiometer throwing a wobbly, you could try this:

http://briskoda.net/forums/topic/146724-re-map-not-feeling-like-it-used-to-read-on/

It's free, so nothing lost if it doesn't work.

Bit of an obvious one but it hasnt been mentioned, try changing the fuel filter? Cheaper than a cylinder head!

The symptoms I had with my cracked cylinder head were mainly coolant loss and awful starting of a morning, I didn't have many symptoms once I was on the move apart from relatively poor fuel consumption and a fairly lumpy idle, saying that, the 2.0TDI has never been one for refinement now has it.

Doesn't the 2.0TDI Scout have an 8v head like the Mk1 Superb? if so the 8v head isn't problematic like the 16 valve BKD head IIRC.

As far as I know misfire events aren't logged on PD TDI units.

Nowt to do with the injector loom or the MAF sensor is it?

Its a sod that it doesn't log a fault code, that was a big factor when it came to diagnosing the cracked head on my car. No fault code = nothing to investigate. Get one of the technicians out on a test drive with you and recreate the fault for them.

Make sure you are persistent, don't be fobbed off by anyone from Skoda, if you don't have any success then you have to escalate it to Skoda customer care.

And yes, a Diesel can have a misfire of sorts, if the unit injector isn't firing when its supposed to you won't achieve combustion in that particular cylinder, no combustion = misfire.

Edited 19 December, 200916 yr by dstev2000

Will try the potentiometer reset and let you know how I get on.

Cheers

I have had pretty much the same symptoms with my 2.0 tdi. Misfires and jerks at 1800rpm, under medium load.

I assumed it was due to sticking vnt or filthy trottlevalve.

I cleaned the trottle and egr housing, threw in a couple of wurth injecion cleaner bottles, and driving it much harder and on higher revs than I use to.

The car now behaves as normal, and i hope it will stay that way.

Good luck.

Well mine is having similar troubles.

For the past 5-6 weeks the car has been developing a misfire. Light throttle around 1800rpm, randomly cuts out under load when pulling away.

First breakdown: Was fine by the time the AA got to it. Got it serviced, faults check, EGR checked, EGR ok, no faults.

Second breakdown: Kept cutting out when any load was put on the engine. Recovered back to the Dealer. Still no faults, but oil

found in the fuel system. Tandem pump and fuel pump replaced, fuel filter etc.....

Ran brilliantly for a day or so, then the misfire came back. Did around 700 miles until.....

Third Breakdown: Went ok again after the AA got out to it, back to the dealer: traces of oil found in fuel filter, tank drained, lines cleaned, fuel filter housing cleaned, element replaced. Still misfires !

Still in at the garage, checks done:

Fuel system drained, cleaned fuel filter changed as above.

Software update (recommendation by Skoda)

Timing found to be out, readjusted.

Injectors swapped out for a "known good" set. Not sure about the wiring loom mind you.

The dealer and Skoda are out of ideas for now, as it still misfires.

Mr AA Man who came out on the third call out reckoned that it it was cutting out then it was a fueling issue to all cylinders. He has heard of VW agents

replacing everything in the fuel system to fix it properly. Tank, lines, the lot ! He believes that there is still oil in the fuel system after the tandem pump

failure.

Car starts ok, hot or cold, runs fine, plenty of power, but unreliable when it misfires or cuts out.....

Ooops, its a:

2005, 2.0 PD TDI

Ooops, its a:

2005, 2.0 PD TDI

Have you had problems with gradual coolant loss? have they tested for excess pressure in the coolant system?

I have a July 2007 2.0 PD TDI and I had the tandem pump replaced, fuel tank drained and checked, lift pump replaced, fuel lines checked/replaced, fuel filter replaced and housing checked and cleaned.

the factory were 100% sure that my problems were fuel related until they discovered a cracked cylinder head. I had cold and hot starting problems and the odd 'fail to start' scenario so I appreciate my symptoms are different to yours. Took 2 years to finally arrive at a dud head conclusion though.

The unit injector loom is known to cause misfire type problems as the loom itself runs through the internals of the head and is exposed to oil, high temperatures and so on, IIRC vibration of a certain frequency is what causes the loom and consequently the injecotrs to misbehave.

I'm not suggesting you have a cracked cylinder head or anything but it goes to show the factory isn't always right and that its a real pig to diagnose a problem without the magic fault codes.

Have you had problems with gradual coolant loss? have they tested for excess pressure in the coolant system?

I have a July 2007 2.0 PD TDI and I had the tandem pump replaced, fuel tank drained and checked, lift pump replaced, fuel lines checked/replaced, fuel filter replaced and housing checked and cleaned.

the factory were 100% sure that my problems were fuel related until they discovered a cracked cylinder head. I had cold and hot starting problems and the odd 'fail to start' scenario so I appreciate my symptoms are different to yours. Took 2 years to finally arrive at a dud head conclusion though.

The unit injector loom is known to cause misfire type problems as the loom itself runs through the internals of the head and is exposed to oil, high temperatures and so on, IIRC vibration of a certain frequency is what causes the loom and consequently the injecotrs to misbehave.

I'm not suggesting you have a cracked cylinder head or anything but it goes to show the factory isn't always right and that its a real pig to diagnose a problem without the magic fault codes.

I've never had a problem with starting it, hot or cold and never noticed any coolant loss. Its just been servviced too, so they "might" have noticed that.

They tried the new set of injectors in it, the technician did say that they were looking at injectors and the loom, so I hope that they tried a loom in it too when they had it

opened up to get into the injectors.

I still think its a fueling issue myself, but I've no idea what they clean the tank with as they don't recommened any detergents. Depending on how badly the tandem pump

failure was, who knows how much oil got into the fuel system and you can exactly wipe all the oil away.

Giving it till the second week in jan then its being traded, but I can't say I'll be going for another VAG in a hurry even if I've just been unlucky with this one.

My PD140 has done this from new and the dealers assured me that it was common on a lot of PD140s and that there is no 'cure' the engine just does that.

However since remapping my car the hestitation, as call it, has vanished. The tuner says they have come across this in a lot of PD140s across the whole VAG range and their map always cures it.

There have been several threads across various VAG forums reporting exactly this 'missfire' with no 'cure' offered by dealers - also my neighbour says his BMW 320D has the same issue

Edited 24 December, 200916 yr by Octavia5

I've never had a problem with starting it, hot or cold and never noticed any coolant loss. Its just been servviced too, so they "might" have noticed that.

They tried the new set of injectors in it, the technician did say that they were looking at injectors and the loom, so I hope that they tried a loom in it too when they had it

opened up to get into the injectors.

I still think its a fueling issue myself, but I've no idea what they clean the tank with as they don't recommened any detergents. Depending on how badly the tandem pump

failure was, who knows how much oil got into the fuel system and you can exactly wipe all the oil away.

Giving it till the second week in jan then its being traded, but I can't say I'll be going for another VAG in a hurry even if I've just been unlucky with this one.

When my new cylinder head was fitted they had to install a new loom as they couldn't remove the old loom from the old head. Might be worth checking to see if the loom was actually looked at because its sounds like a pig of a job to change.

I know what you mean about VAG cars though, recently got my car back after it was off the road for 6 weeks in total only to find the EGR cooler pipe has just split, now my car is off the road until at least the 29th and I wanted to use it over christmas :(

My PD140 has done this from new and the dealers assured me that it was common on a lot of PD140s and that there is no 'cure' the engine just does that.

However since remapping my car the hestitation, as call it, has vanished. The tuner says they have come across this in a lot of PD140s across the whole VAG range and their map always cures it.

There have been several threads across various VAG forums reporting exactly this 'missfire' with no 'cure' offered by dealers - also my neighbour says his BMW 320D has the same issue

This isn't hestitation on mine, its a misfire alright and has only recently developed. I had hesitation on my MKIV R32 and that was cured by a software update...

On my list to ask the garage:

Was the Fuel temp sensor cleaned/replaced after the tandem pump failure ?

Was the Injector loom changed for a "known good" one when trying different injectors ?

Is EGR clogged, even if vagcom says its functioning alright.

I'll keep doing my google search to see if anything else comes up....

When my new cylinder head was fitted they had to install a new loom as they couldn't remove the old loom from the old head. Might be worth checking to see if the loom was actually looked at because its sounds like a pig of a job to change.

Cheers, was going to ask them about the loom, as the last time I spoke to them they only mentioned changing the injectors over and

no mention was made of the loom. I just hope they don't say they did, if they didn't if you get what I mean......