'Interesting' starting problem

[Reggit 0]

I'm got this 'interesting' starting problem with a warm (not hot or cold) engine, it does the following;

 

1. Turn key to start position - the engine spins over but won't fire.

 

2. Turn off then back to start - the engine won't spin.

 

3. Off then to start again - starts normally as you would expect.

 

Recently I've changed the usuall suspects for genuine VAG items, fuel pump relay, ECU relay and ignition switch.

There are no recorded fault codes.

 

I'm considering changing the blue temp sensor as it's about 5 years old now, and the only thing I could consider to be causing a heat related non-start.

 

The car starts perfectly when cold or hot, it's just when it's cooled a bit I get the troubles.

 

Anyone got any ideas as I'm stumped?

[fla 9]

relays seated properly? When it turns over (scenario 1) is there a spark? Is the immobiliser OK? Fuel pump also ok?

[Reggit 0]

Relays are seated properly. Don't know if there's a spark as I've never bothered pulling a plug out and trying again (when knowing my luck it will move on to number 2 and 3).

 

Fuel pump is good - whines a little, and is on the list for replacement, but still works OK.

 

Immobiliser is thought good, it's about a 3/4 years old cobra unit.

 

It's just puzzling me as to why it always needs the 3 turns of the key to start when warm. :scratch:

[pummer67 0]

if its blue temp sensor normally the engine runs rich and revs can be very slow at returning and idle is faster when warm engine. You could get a couple of resistors from maplins which cost pence and plug them in to the blue plug. This proved my blue sensor was knackered. Or you could just change it. Mine was about 5pound from gsf. Mark

[mic_VR 3]

Mines been doing this for pretty much as long as I've owned it, it starts second time everytime when it's kind of half warm.....

 

Loads of people have looked at it including my local VW stealer and no-one has the answer, but i've just got used to it now so don't notice myself turning the key twice.

 

Be very interested if you find a solution!

[jamiehamy 0]

mic_VR - I've got the EXACT same issue. Second time everytime when half warm.

 

I'm glad I'm not the only one. As you say, I get used to turning twice, but would be nice to sort. Only started after I did the chains ( I think), so possibly timing is fractionally out or i upset a sensor somewhere - nothing showing on VAGCom tho. She runs perfectly too, so I can't imagine it was that.

 

If I find a cure, I'll let you know, if you find it first, please give me a shout!

 

Cheers

[Rob_B 0]

oil pump relief valve possibly? there is a pressure relief valve in the oil pump which can get stuck which causes the engine to not start. i had this on my G60, changed the oil pump and winner winner

just a thought...

[Supercharged 2]

oil pump relief valve possibly? there is a pressure relief valve in the oil pump which can get stuck which causes the engine to not start. i had this on my G60, changed the oil pump and winner winner

just a thought...

 

Good call! - This seems to be a fairly common one on VR's and I know of people that have chaged most of the above to fix it but no no avail... not many would think of the oil pump though but it makes sense!

[Rob_B 0]

oil pump relief valve possibly? there is a pressure relief valve in the oil pump which can get stuck which causes the engine to not start. i had this on my G60, changed the oil pump and winner winner

just a thought...

 

Good call! - This seems to be a fairly common one on VR's and I know of people that have chaged most of the above to fix it but no no avail... not many would think of the oil pump though but it makes sense!

 

it does something like hydraulic up the tappets from what I understand. I only changed mine because I put a replacement oil pump a couple of weeks beforehand, then I started having problems