VW transporter very rough idle

[installer]

I have a t4 transporter 2.5tdi code ACV, my problem is after about a minute of idling from cold it starts to splutter and runs really really rough, beyond rough.. its fine while driving but as soon as i stop and leave it idling it starts again..

Any one got ideas as to what the problem might be.

1 suggestion was th ECT coolant sensor may be faulty but i cant find any other evidence on the web to back this up.

 

[Joe1989]

 

[installer]

Thanks for the reply but i'm not sure how to interpret the info, the full picture does not download when i try to view it..

Cheers..
installer

 

[Joe1989]

Bascially it could be any one of they things, but strangly it dosnt mention the coolent sensor...


Is the engine check light on, if so might be worth going to get it read

 

[installer]

Thanks Joe, actually looking at it now, on the first section it does mention the ECT sensor, also the EGR soenoid and EGR valve, its not smokey so doubt its egr related (not that i know much about it) no check engine light comes on, for the sake of a tenner i might just try replacing it, thanks again

 

[Joe1989]

oh aye, lol nerver noticed it! lol

Might be worth trying to replace it but i would have though the temp gauge wouldnt work if that was faulty ?

 

[installer]

was thinking the same myself, but have read that other VW diesels have 2 or 3 temp sensors, one for the ecu, one for the temp gauge and so on...

have seeen the sensors on ebay for a tenner or less but will try the main dealer here for a comparison.
thanks again joe, appreciate the help..

nice to have 2 heads on a problem..

 

[Joe1989]

no worries mate, might be worth getting the sensor if its only a tenner!

Sorry cant be more of a help lol

 

[Ja5]

Hi

When you say it drives fine, what revs does it stop running rough ?? Can you drive around then say stop at lights and it happends straight away??

Jason

 

[installer]

yes as long as its warmed up as soon as i go below about 1000 1200 rpm it coughs & farts like a trooper... (not isuzu lol) if i hold open the throttle a little just over the "threshold" its fine, but opened up on motorway it'l top a ton ten... been like it for last 2 years (since i got it) just hasn't been high on priority list ...

 

[theredbaron]

if you have put bio diesal in that will be the trouble if you buy your diesal from morrisons there diesal has got a percentage of bio init hope this helps

 

[installer]

no bio diesel, just regular its a fault somewhere, just need to get to the bottom of it.

 

[Mr Parsnip]

Check if all your vacum leads are in order n also ur air flow meter....

 

[HORUS]

try the fuel filter if it has a tpiece return pipe it can draw air and cause air bubles on idle
the fuel return stops this at higher revs cheaper alternative ?

 

[hollow]

usually on vag diesels when the ect coolant temp sensor is duff the vehicle will use more fuel than usual. it will also go faster due to it telling the ecu the engine is cold always .thus giving the engine more fuel to warm the engine quicker.

never seen it cause erratic idle .

try unplugging the maf sensor located just after the airbox .
should drop to ecu defaults. if maf is knackered erratic idleing will be gone.

 

[TheCheekyMonkey]

if you have put bio diesal in that will be the trouble if you buy your diesal from morrisons there diesal has got a percentage of bio init hope this helps

i`m curious as to why you say this? i understand about biodiesel and have used it, but i`m just wondering why you would say that this is the exact cause of it without a bit of enlightenment....

 

[Mr Parsnip]

what i would do is just take it to a good respectable garage n get it read on vag com.

then you will know for sure what the problem is.


or why don't u buy one of the following and do it yourself.

VAG Car Diagnostic Scanner Fault Code reader COM on eBay (end time 01-Oct-10 12:39:19 BST)


Ive seen these working all u do is match the fault code up in the manual and it tells you what the problem is....


mr p

 

[nutter]

Hi did you ever sort the idle problem,
as i have the same and read through posts but found no answer.

 

[swissy]

I had this exact same problem on a 2005 transporter, turned out on mine that it was the flywheel that was knackered, cost me £1400 to put right.

I hope yours isn't the same problem.