2.5, TDI Quattro 2002 Starting problems when engine is already warm

[ColinSA]

Hi all I have a 2002 A4 2.5 TDI Quattro .The car starts fine in the morning and there is not much white smoke .It takes about 45 mins to get to work and the temp needle stays in the middle of the gauge at about 90.When I park the car and leave it for upto a half hour she will start but if left for like an 1hr or 2 ,she refuses to start and the glow plug indicator light comes on . I have to wait untill the temp needle has dropped to nearly cold again before she will start again. About 3 months ago Audi SA put the VAG machine on and cleared the glow plug indicator fault light and told me no fault could be found .Anyway it recently happened twice in 3days and i took the car back to Audi and with the Tech he put the Vag machine back on and Code 01376 came up which says on the machine itself rpm sensor on injector pump. Now this is where the fun and games begin they( Audi)firstly say replace fuel pump then the next mechanic says no its the needle lift sensor ,then the next one says no its the injection pump then the next one says its the injection pump delivery ,then said its a process of elimination and all these parts will need to replaced so they can actually find and fix the fault , Audi has confused the issue by all the possibilities so at the end of the day i am no wiser as to what the actual fault is and exactly what needs to be replaced .The car does not cut out whilst driving and she is not underpowered at all.
The glow plug relay has also been recently replaced.
Where does one find the following on the car , needle lift sensor .fuel pump and injection pump ?
Any suggestions would be most highly appreciated.

[mikeybutch]

I have an 04 2.5Tdi with 110k.It had this when bought about 2yrs ago and tried lots to cure.It would start when warm but only after lots of cranking.A faulty needle lift sensor was diagnosed and changed which made it less smokey but did not help starting.Its the injector in the left bank with a wire middle one I think.They are expensive over £400 with labour and I would not let them change this unless it defo shows as a fault.Wont be the glowplugs cos it starts when cold but it could be timing.Mine had no record of a belt change only a previous owner saying this had been done so mine went to our member Adamms24 Chris is an expert and he found the timing way out when he did the belts etc .Its now a perfect starter.How long have you had this what miles is yours and when and who did the last belt change?The timing is very tricky and its no good doing hastily.Chris spent a long time just retiming mine.Hope its not the pump which is expensive

[ColinSA]

Thanks for your response
The car is 2nd hand and I have had it since 2007 and it had 177000kilos on the clock . According to the service book cam belt was done at 135000 kilometres by Audi themselves,the clock is now on 200000kilos and the services have been done by Audi . The last service was done at 189000 and was very expensive around R7800-00 South African Rand, and that was just for a normal service no replacement of brakes etc.
Is there a way I can test the fuel pump and or injection pump but please take into consideration that I am not a mechanic so when you explain please be specific as to locations and how to test .
When the car starts again there is also no loss of power just the flashing glow plug indicator which goes off by itself after 3/4 days

[mikeybutch]

It does seem that its something to do with the fuel pump which I have heard of but dont know much about.I would think about getting another specialist opinion cos I dont like this idea of you paying while they change parts on a trial and error basis.The only other thought is that there are temperature sensors on diesel engines which can affect starting if they fail to tell the engine that it is hot and it is sett wrong.I am thinking that if the sensor has failed it may be affecting the fuel supply when hot and thats why it doesnt start but still runs well.They are simple and cheap to change but again should show up on diagnostics

[ColinSA]

Thanx once again for response mikeybutch ,but again i need to find these sensors on the engine so please be so kind as to guide me to the exact positioning . I actually do recall one of the Audi techs mentioning something about a temp sensor.
Any help with be highly appreciated .
Regards
Colin

[mikeybutch]

Its under the engine cover towards the front just to the left of centre.Sits upright with a cable plugged in on top.Mine is green and its held in by a twin bladed clip .My son helped change mine and it seemed simple just to slide the clip off pull out the sensor and plug in a new one.But it should show up if its faulty although still worth trying.Great if it works . Mike

[ColinSA]

Hi Mikeybutch
Thanks this post really helped me I located the temp sesor just to the left of the injection pump and mine was also green .I have had to go to the agents ( Audi ) and here in SA they r not cheap ,but I got one anyway and replaced it . I
Will test the car over the next couple of days and let u know if she starts after an hr or so when warm.
Thanks one again
Colin

[mikeybutch]

Well done hope it fixes it