Help please - Audi fault P1570 - intermittent starting when warm, but not when driving!

[soulsister64]

HI there

I have a convertible 2005 2.5 TDI V6 and having looked on other threads my problem seems to differ from others so im looking for some advise if possible, before I go spending a lot to try and get it fixed !

A few weeks ago my car after running it all day (warm day) would not fire up, it cranks like its trying but will not start, prior to this the car has had no other issues, tried a few times within that hour to get her going but no luck ! it try's to start but wont turn over, goes to the car the next day, cold start fine no problem, decided to get her checked out and it had 3 faults, the ECU unit was removed and sent away and the faults noted on that came back as no problems, and had 3 weeks more of running her fine ! Although though I've been taking my time and only short runs to and from work, so its been a cold start each time,

Last week however after a 12 mile run in hot weather I had left it about an hour the car failed to start again ! again tries but no luck in starting her, went back 3 hours later car started like nothing was wrong !! So back and had her checked again and the problem is coming up P1570 fault, been on the internet doing some checking on websites and checked wiki.ross-tech.com/wiki/index.php/17978/P1570/005488 but all the issues seem to differ to mine, whereby the engine cuts out when driving, mine has never done this..

The non starting only seems to happen when the car is warm, like a relay is breaking down or immobiliser is not connecting when its warm.. its there a relay connected to the fuel pump that may be the issue? or key/immobiliser link that breaking down

So any ideas would be appreciated or if anyone else has had this issue??

thanks in advance

Alison

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[NHN]

Well it doesn't appear to be immo as yours isn't even starting, usually they start but cut out after 3 seconds or so.

What's the turnover like, does it sound slower as such when its warm, as starters suffer with heatsoak after a while & can be issue starting when hot, coolant senders, common issues for starting.

 

[soulsister64]

HI there, yes it does sound a little slower when cranking well doesn't sound like it normally does !

Any ideas?

 

[soulsister64]

Bump. Drove car home tonight no problems starting from cold as normal around 10 miles. Parked up Left her on the drive and went to re start her 45 mins,later and will turn over but not start. ?? Been looking on sites. Crankshaft sensor ?? Green coolent sensor. Or even a relay breaking down that prompts fuel pump ?? Still coming up immobiliser fault nothing ekse. Which i can only assume is due to it not starting. but I've ruled that out. Got to be some thing else surely ??

 

[studunc06]

dont think it would be a fuel pump issue as there would be enough residual fuel in the system to start it then it would cut out. crankshaft sensor sounds most logical but i have heard of people having issues with relays of some sort that live under the ECU i think and also on a footnote i have heard of starter motors failing to work properly when warm.