mk4 golf tdi strangeness

[Big G]

ok so the golf is a '98 1.9 TDI 110bhp version with 274k on the clock and still the original engine. Never had a head gasket gone/replaced afaik and I've known the car for 150k+ of it's life.

Drove it 20 miles tonight and stopped to get a takeaway. it's gonna be half hour so we decide to pop to my Dad's to wait and then return. After returning to the car it won't start. it turns over like a petrol does without spark plugs... Tried several times to start without any luck. Tried locking it and unlocking it. still nothing.

Cambelt is intact and everything is spinning as it should when turned over. I removed the mickey mouse clip off the to top of the fuel filter and turned it over again and saw fuel coming back from the pump.

Since it was already hot I ruled out heat. fuel returns from the pump so can practically rule out the fuel. the only thing it must be is compression right? Car drove perfectly before.

so my dad turns up to tow me home and we decide to roll down the hill I'm pointing down to see if it'll bump start and it does... so we turn the engine off again to see if it'll start off the key again. it won't. bump it again and it starts grrr. so we stop next to the tow car to demonstrate it turning over and the bloody thing starts first time!

So I drive back to dad's and park on the hill just up the road from him and try to start it again. it won't start off the key lol.

time to investigate in the daylight tomorrow now.

Any ideas?

[spud31]

think ive commented on this before a pd tdi will not inject fuel unless its spinning over above 260 rpm.
If your is a arl engine code check the anti shudder valve infront of the egr is opening as if its stuck closed will not fire

[Scotty15]

Hi Big G
We have the same model of car and spud is right about the starting speed etc. A good test is if you remove the temp sensor wire located on the near side of the engine above the clutch area and try to start it when it is hot then the most common thing that cures the problem is a new starter motor as it has on weak and is not spinning fast enough.
Our car does the same thing but I have not got around to replacing the started motor.

Andy

[cmgreen]

think ive commented on this before a pd tdi will not inject fuel unless its spinning over above 260 rpm.
If your is a arl engine code check the anti shudder valve infront of the egr is opening as if its stuck closed will not fire

Car is a none pd engine.

Souns werid but have u got a second key? Try thats, sounds like the immobilser is kicking in.

[Big G]

true, it's pre-PD. AHF engine.

If it was the immobiliser kicking in surely it wouldn't start off a bump?

When you turn the key it sounds like the engine is turning over very fast. like I said it sounds like a petrol does when you take out the spark plugs.

Off to have a look at it now in the daylight.

[lsdevey]

hi there iv had probs with cranck poition sensors in the past.have u rev counter signal we crancking ?:o

[Big G]

Revs aren't moving no. It seems to have fixed itself now. It also appeared to only happen when hot, but after 20 miles it started fine again. Just don't get it.

[lsdevey]

with out putting it on a diag tool to get codes just a educated guess but i had a customer cum to me a few weeks bac with very similar symptoms would only start sum times and wen it wouldnt start always started of a tow replaced crank position sensor now no probs .that was also a tdi :thumbsup: hope this helps

[Big G]

Vagcom showed 01206 error with valve near egr. Cleared the fault code and it hasn't returned yet, but it still had problems for sometime after

[lsdevey]

wen that valve pacs up, wen u turn ur car off the engine judders it also blows a ten amp fuse in the engine bay fuse box cant remember wat number fuse sorry

[lsdevey]

forgot 2 mention fault goes wen cleared but usally cums bac after 3rd time you start vehicle

[Big G]

I'll rescan it in a bit then. Just doing some rc car work lol

[lsdevey]

ok bud hope was sum help if u have any more probs pm me:thumbsup:

[teambowen]

Gareth.
check that the turbo waste gate isn't jamming or sticking closed.
this will stop the engine breathing and also firing.

Just a thought.

Jamie.

[mark christopher]

Gareth.
check that the turbo waste gate isn't jamming or sticking closed.
this will stop the engine breathing and also firing.

Just a thought.

Jamie.

go on then explain that comment!!

because as a 25year plus mechanic i know thats bollocks..... waste gate controls boost pressure and will be shut until the boost is reached, and to reach bost it needs the engine to run......
god i love arm chair mechanics :thumbsup:

[Miggers]

Make yourself a member here,it's free:

http://www.tdocuk.com/

What the boys on there don't know about turbo diesels isn't worth a shat.

They've helped me out a few times when my Pug Hdi has been acting the cock.

[spud31]

Thats the asv (anti shudder valve) i was on about, if this sticks closed engine acts like it has no compression.
does sound like imobilser is not letting pump inject fuel as there is a solinoid inside the pump that allows this using the needle lift sensor on no3 injector to work out when to fire other injectors.
http://wiki.ross-tech.com/wiki/index.php/01206
covers your fault code