Warm start advice needed please

[johnb48]

Seems like a few people have warm start issues
Starts first time when cold but a short or long journey and it churns away for 5 secs before starting
Golf mk5 04 reg 1.9 TDi BKC engine code

AM i right in thinking if it was, the mass air flow meter or engine temp sensor then it would show up on the fault codes ?
because i have no fault codes
I have swapped the air flow meter to no avail
Can someone tell me where i find the engine temp sensor ? is there more than one ?

Also heard this relay may fix the issue ?
Number 109 ECU Relay / Fuel Pump VW Audi Seat Skoda Diesel Meyle Germany | eBay
where is that located ?
Thanks John

[davidevans]

John, I fixed a longstanding and rapidly worsening hot start problem with our 05 1.9 tdi BKC golf SE last night by fitting a new starter motor. I had no fault codes either and took the plunge after tons of research on the web and the forums. Car is transformed. Not saying it'll work for you, but worth considering. Those in the know advise that you really need VCDS to properly check your starter rpm as it must exceed a preset value in the ecu to start when hot. I understand that worn starters can't always spin quickly enough. I don't have VCDS so took a calculated risk. Hope this is of some assistance and good luck.

[johnb48]

John, I fixed a longstanding and rapidly worsening hot start problem with our 05 1.9 tdi BKC golf SE last night by fitting a new starter motor. I had no fault codes either and took the plunge after tons of research on the web and the forums. Car is transformed. Not saying it'll work for you, but worth considering. Those in the know advise that you really need VCDS to properly check your starter rpm as it must exceed a preset value in the ecu to start when hot. I understand that worn starters can't always spin quickly enough. I don't have VCDS so took a calculated risk. Hope this is of some assistance and good luck.

Thanks for that mate its certainly looking that way....
I work next door to a VW breakers and have had all sorts for free inc dual mass flywheel clutch !
So I will be paying them a visit and give it a try thanks

[nevo]

Fit a new one, your starter or battery are getting tired,most likely the starter,you can check by disconnecting the temp sensor to simulate a cold start went its hot,I think the threshold for a warm start is 275rpm when cranking,a breakers starter will probably under perform also,also when you remove it look for gunge from the dmf it may have got into the starter.

[davidevans]

Fit a new one, your starter or battery are getting tired,most likely the starter,you can check by disconnecting the temp sensor to simulate a cold start went its hot,I think the threshold for a warm start is 275rpm when cranking,a breakers starter will probably under perform also,also when you remove it look for gunge from the dmf it may have got into the starter.

Hi Nevo, interesting that you mention a possible link between starter degradation and DMF wear. Our DMF failed catastrophically a few weeks ago (thread elsewhere here and in more detail on myturbodiesel) and the resultant junk locked the whole transmission. There were even bits in the engine bay and under tray. I'm sure it wouldn't have done the starter any good if it's been shedding debris over along period of time.

[Borab0y]

Mine was fixed by changing the threshold for the warm start cranking revs in the ECU but this was done by altering the ECU map

[nevo]

Boraboy did you have a full remap or was it specifically changing the cranking threshold,its getting to be a pain in the you know what.

[Borab0y]

I have a Viezu map that I read out from the ECU using a MPPS cable, a guy I know in the Netherlands then altered the cranking threshold.

[gill2610]

I have had the same hot start problem for a while with golf 2.0 Tdi Gt Sport 08, no codes show. I replaced the battery and it sorted out the problem, happiness for one week, now it has the same problem again, not as bad but sure it will get worse as that is what happened before. I also have a slight judder at idle. Someone mentioned a new DMF, can that have anything to do with the problem. I am a bit annoyed that a 2008 already has problems. I would be grateful if anyone has any ideas, I am loath to try expensive things that then don't solve the problem. I would be more than grateful for any help.