Passat WARM start problem

.Longshanks.

The boss has a 2008 2.0TDI VW Passat with approx 100k KM’s and recently it’s been giving him trouble on warm starts. Starts 100% every time from cold, but if he takes a quick trip to the shops etc it could be the 5-6 time before it kicks in.
He has already got the fuel pump replaced but it remains a bit of a mystery.

Anybody any experience with this or suggestions?

Dades

What happens when he puts the key card in? Does it turn over and not catch?

mullingar

Ive heard of a few causes of this ranging from temp sensors to MAF's.

I know someone who had a similar problem (rep mobile), the fix was the starter motor! Apparently the bearings in the starter motor got hot from the hot engine and restricted the speed of the starter.

Simple check:
Find somebody with the same 2.0 TDI engine as yours(Audi/Skoda etc), listen to the speed of their turn-over and compare it to yours when both hot

.Longshanks.

Dades wrote: »

What happens when he puts the key card in? Does it turn over and not catch?

As far as I know yes

mullingar wrote: »

Ive heard of a few causes of this ranging from temp sensors to MAF's.

I know someone who had a similar problem (rep mobile), the fix was the starter motor! Apparently the bearings in the starter motor got hot from the hot engine and restricted the speed of the starter.

Simple check:
Find somebody with the same 2.0 TDI engine as yours(Audi/Skoda etc), listen to the speed of their turn-over and compare it to yours when both hot

Its not my car but i'll pass the idea on and see if he know's anybody else with one to compare. I know I dont - at least not close to work

benny_cakes

Had a very similiar problem on a 99 golf tdi some years ago when it was hard to start when hot & was told to fit a 2ohm resister to the coolant temperature sensor & car has gone perfect ever since! Coolant Temperature sensor & the starter motor as already stated are the 2 most likely causes.

GTE

benny_cakes wrote: »

Had a very similiar problem on a 99 golf tdi some years ago when it was hard to start when hot & was told to fit a 2ohm resister to the coolant temperature sensor & car has gone perfect ever since! Coolant Temperature sensor & the starter motor as already stated are the 2 most likely causes.

Although that may work, if you are able to get to the sensor wiring to do the bodge you may as well just change the sensor. That way you know the glowplug system and other things are working when they should, such as GP activation while you drive. The resister is fooling the ECU into thinking its a different temp outside.

I had to get mine replaced in my 2000 TDI and I had to replace the sensor and the wiring because the previous garages bodge failed miserably. Wiring was ****e.

Since its a 2.0 TDI and from 2008 I wouldnt say the temp sensor is a very good chance of being the problem. It was a huge problem (well, small enough really) for the older 1.9 TDI's around the mark 4 era because the sensors were badly designed or built but I hope it is because they are damn easy to fix.

cyborg

The starter motor is to blame for a lot of hot start problems on the vag engines but instead of replacing the starter the ecu can be reprogrammed to fix this. the ecu doesnt inject diesel if the starter spins the engine at less than 200rpm when warm.By remapping the ecu to inject fuel at lower rpms it will start fine when warm.

scooby girl no1

or it can be only a matter of changing programme in ecu
I often recommend this people SportChip, they have some info about it on their website

Kee01

Have a 1.9tdi VW Caddy (05) with the same problem. Cold start is fine but when warmed up I have to turn the engine for a few seconds before it kicks in. Thanks for tips...:)