GOLF/A3 2.0 TDI Starting Problem can anyone help?


Jul 16, 2009
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my dad has the MK5 GOLF TDI 2.0 140BPH, it is the same engine as my A3 and he is having problems with it starting, it takes alot of turning over and it is lumpy when it starts, it does this when its HOT, it starts better when cold but is still lumpy?

He has changed the glow plugs, as we where told that it could be that but still no change!

also had it on the diognostic and it brought up no fault codes, can anyone help?



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I got the exact same fault. Actually starts better when cold. I've changed quite abit but still no cure. When I remember what I changed, i'll post it
cheers, that would be great.

Some people suggested it may be a MAFM (mass air flow meter) but they are £109+vat not cheap if we dont know if it is that, and i personally cant see how that would effect it.

Disconnect (unplug) the engine temperature sensor (RHS rear of block), should then start as normal. Then reconnect sensor.

Not convenient but cheap and handy if your stuck somewhere.
Can i do this when the car is hot or do i have to do it from cold?

Do i stop the car and reconnect and then start it, or re-connect when it is running?

will this cure the problem of starting when warm?
This is a pit stop fix not a long term solution.

When my old Golf had this prob (ie not hot starting), I unplugged the sensor's connector, started then plugged straight back in while running.

Never tried it on a cold engine.
Temp sensor and replacement O-ring isn't that expensive, I had to change mine was about £25 all in from a dealer (price from memory).

Not too bad to change and if you are quick on a cool engine, you can do it without loosing too much coolant.

I am thinking about changing my coolant temp sensor as well but am having trouble locating it. Please can you let me know where it is hiding or does anyone have any pictures ?
There is a coolant pipe arrangement on the right hand end of the block (when viewed from the front of the engine) and the temp sensor is on the rear end of it (end nearest the bulkhead).

Cheers i will let him know, if this doesnt not cure it what else could it be?
torsion timing is out can cause lumpy idle.
as to the hot start i have same fault can be fixed by getting car remapped to inject diesel when hot and cold. as standard it dosn't inject when hot...
I had this on my old 2.0 tdi. i changed the temp sensor but was just the same after.
torsion timing is out can cause lumpy idle.
as to the hot start i have same fault can be fixed by getting car remapped to inject diesel when hot and cold. as standard it dosn't inject when hot...

Okay, how much did i cost you? and where would be the best place to get i done?

Volkswagen, or JABBA SPORT=(My local tunning specialist?)

or is this somthing that can only be done by a dealer?

I would also be interested to know where this can be done as changed the coolant sensor and has made no difference!
Mine (2005 2.0 TDI Sport) has always been crisp from cold, but worse when hot. I would say that in the 20,000 miles I've had it it's deteriorated as well, but I have heard enough stories of this nature to believe that all the 2.0 TDI engines are the same. It's really no good!
If I took my car to Audi would there be any software or ECU updates available for my 2004 car ?
I wonder if the hot start problem is just in early A3's or if it is affecting any age A3 ?
I think it the ''ENGINE SPEED SENSOR''
If it is the engine speed sensor why is it only effecting the car when it is warm and not from a cold start ?
I have the same problem and had my speed sensor replaced on friday, and what do you know....failed again today and left me stranded.

Not goo to have spend £220 onf Friday at Audi to have the problem come back 2 days later:sob:
After ringing around many vw and audi specialists today and being told "we would have to plug it in sir to see what faults there are" I spoke to one specialist who says that he knows exactly what is causing the hot start problem but wasn't prepared to tell me over the phone as he said I could then easily go somewhere else and he doesn't like to give business away.
Basically he said that if it didn't cure the problem then I wouldn't have to pay, but he is sure that it would and is quite common on these cars. The cost to fix it including the labour is £218 ruffly so I was wondering if anyone that knows how much audi parts are has any ideas what it can be?
I asked him how he was so sure and he told me that he has worked for audi for 15 years and is a master tech, are they any good lol ?
I have the car booked in for Tuesday and he has ordered the part ready. I am thinking that it might be an EGR valve, MAF sensor or maybe an IMF ? Any help is appreciated.
I've heard of this problem before and also recall some kind of 'fix' that had been proposed by someone which basically isolated some component temporarily, while starting occured.
I wish I could remember the name of it now..

The most popular 'workaround' advice seems to be to depress the clutch and start without touching the throttle at all.

Update: What's known as the Hamman/Hammond mod seems to be the solution I saw. Seems cheap but may be complicated/scary to implement.

Mentioned here:
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Do you think you might be able to remember what the 'fix' was as it would really help and might save me a bit of money ? :)
The linky I added to my last post is well worth a read, I'm not much of an engine tech I'm afraid. The final posts on that thread suggest even an old battery might be a/the cause.
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That is an interesting read :) I wonder if it could be my starter motor ? Better try the clutch pedal trick.
I worry about doing things like this and would prefer to get to the bottom of the underlying problem lol :)
Have picked my car up from the garage today and guess what.............the car now starts when it is warm :yes: I can't believe it. Would anyone like to have a guess what it was ?
Have picked my car up from the garage today and guess what.............the car now starts when it is warm :yes: I can't believe it. Would anyone like to have a guess what it was ?
do tell!!

IMF? Crank sensor? Temp sensor? New battery??
All of the above?
Nope none of those, it was the starter motor. The mechanic who defo knows his stuff said he has seen alot of these on this engine throughout the VAG range cause the problem. Wish i hadn't wasted money changing the fuel temp and coolant temp sensors first though lol.
Yes, the starter motor is metioned in that thread. Was he (the mechanic) more specific or was it just a replacement started motor and nothing more said?
He did try explaining stuff to me but I was in a bit of a hurry when I picked the car up, I think it is to do with not cranking at the right speed.
How much is a replacement starter motor just out of interest?

More problems with my A3, it's becoming a **** to start cold and warm now.. Sometimes it will fire with a 2 seconds and sometimes it won't, but yesterday it was turning over for a good 8 seconds and finally started, who said German motors were bullet proof eh? The car has been scanned recently and nothing showed up on the scan.

Still think the A3 is the shizzle though!

I think i have a spare PD140 BKD starter motor laying in my garage if you need one.

Had same problem hot starts were embarrassing turning 4/5 times before starting.

Loads of garages suggested Dual MAss Fly Wheel, temp sensors etc however I had a gut feeling that it was the starter motor. Bit the bullet today with a brand new bosh SM and the car now starts perfectly.

I hope this helps as it was driving me mad and desperate not to waste loads of money.
Hey guys thank you very very much for the info in this thread!!! I have had this problem on & off for a while now but it has got pretty embarrassing of late! With a few people looking @ the car trying to turn over as calvinc points out above.

As this issue is such a problem with A3's maybe this should be a sticky?

Good s**t guys :)
Hi everyone , this is my first post and I am having the same problem starting my A3 2.0 tdi when warm . It starts first time every time from cold but like a few people have said before once driven for 20 minutes or so it takes 20_30 secs to start . I have the bkd engine and its recently been serviced and I thought this might cure the problem if it was a bunged up air filter or something , but having trawled through a lot of forums I am starting to think a new starter motor may cure the embarrissing problem , its a 2005 2.0 tdi dsg sportback with 84,000 miles on the clock .
I phoned Audi where it was serviced and told them of the problem and they said they would rather plug it in to the computer for any faults , but when I said that it had just been serviced and no fault codes came up they phoned back and gave me a price for a new starter motor but said they could not guarentee that it would solve the warm start problem , so what is the concensas , should I bite the bullet and gamble on a new starter moter ?
Any sugestions would be much appreciated , Thanks a lot you guys , I know you know your stuff .
It could be the starter but maybe try as above disconnecting the temp sensor? as 20-30seconds sounds VERY long to re-start. I test drove a 54-reg TDI Sportback that suffered this too, it took quite a few turns to start when warm but nowhere near 20-30seconds, more like maybe 3 or 4 seconds instead of the instant 0.5 second it should be.

Shame "computer says no" AUDI are not much help but it does not surprise me!