3.0 cdi viano 1998

[stevowozz43]

Hi,
Engine crank taking about 2 seconds to start lately and on 3 occasions during this cold spell it would not start despite about 7 or 8 attemps after not using it for around 12 hours.Had to use easy start reluctanty which enabled an instant start.
Once running and warm it restarts ok for the rest of the day but still a bit sluggish.
Glow plugs, relay and battery are all good.I am starting to think injector issues but once running it drives very well.
Any suggestions on what to look at next would be much appreciated.

 

[stevowozz43]

Hi, sorry but it is a 2008 and NOT a 1998!
(Senior moment!)

 

[BTB 500]

I guess you mean 2008 rather than 1998!

Does sound like it could be injectors - what's the mileage?

 

[stevowozz43]

It's 140, 000

 

[stevowozz43]

Can STAR show a possible injector problem or does it need a practical test and if so how is it done?

 

[CapnCol]

You can check the rail pressure with star. One of your injectors may be leaking down, or pressure reg "O" rings damaged

 

[stevowozz43]

Thank you for your comments.
Have tried to start car this morning after 12 hours and again it will crank well but not start.
Could it be a rail pressure sensor or fuel sensor causing this problem and what would be the symptoms? Last diagnostic showed no faults.
Thanks again for your ideas.

 

[stevowozz43]

Hi all, have just attempted to start car again and now with a temperature of 5 degrees it started!
Seems it only has a problem with 0 or lower.Could there be a specific reason for this?
Thanks

 

[Mike Edwards]

My 08 model 120 Sport started perfectly every time over it's 130k mile lifetime. Of course it then struggled to start when I tried to start it after leaving it sitting for a week in freezing temperatures.

It's off with it's new owner now but I'd be interested to know what could have been the problem.

 

[stevowozz43]

Hi all, would really appreciate some more feedback about the problems I am having with my viano.This is a working car and with business scarce any savings on repairs would be welcomed.
Thanks again.

 

[stevowozz43]

Hi all, took car into Mercedes main dealer for diagnostic and once again it showed no faults.
The injectors showed no faults either. Car still has a lazy start up when warm and still impossible to start when very cold and left for 10 hours or more but cranks well.
Not sure if there is anything to check!
All ideas crazy or otherwise are welcomed.

 

[CapnCol]

Main dealer should have looked at live data> fuel rail pressure to check if thats ok. Otherwise you may have fuel draining back to the tank, so start looking for air leaks in the fuel lines / filter housing etc:

 

[BlackC55]

It is very likely to be caused by a faulty glow plug control unit. they do not usually leave codes either

 

[stevowozz43]

Hi all, have fitted new glow plug relay and whilst the start up is still a little sluggish I can not really put it to the test as the temperature is now well above zero! Have been advised by merc that although I have fitted a Bosch fuel filter 3 weeks ago I should change it for a Mercedes filter as this may be the cause of the sluggish start up. What do you think? Thanks again for your replies.

 

[Dieselman]

Have been advised by merc that although I have fitted a Bosch fuel filter 3 weeks ago I should change it for a Mercedes filter as this may be the cause of the sluggish start up.

I think you should. The logo makes all the difference...

 

[custom 319 v6]

i had the exact same problem with my om642 v6 sprinter at 155k,star machine showed no faults,had a new set of injectors which sorted it

 

[stevowozz43]

Thanks for your comments.I am working on the problem.
New issue now! Auxiliary fan came on perminately two week ago when the outside temp was cold.air con not on and engine temp showed about 80 degrees once warm. Replaced the relay and all ok until today because now it is running all the time even on cold start up. Could it be a thermostat?

 

[stevowozz43]

Hi all,
Latest on sluggish start up.Have been advised to look at the fuel pump as a possible cause as it may not be priming correctly.Does anyone know how many pumps are on the W639 V6 CDI and is there a simple way of testing them to see if they are ok.Also many threads talk about O rings perishing, do I have o rings on this modern engine?
Mercedes have offered to do an injector test with test tubes at a cost of about £300 which I am trying to avoid.
As mentioned before car starts every time now the weather has improved but it is still sluggish and I need to get to the bottom of this issue with as little cost as possible.Please can anyone offer some advice.

 

[BlackC55]

There are two pumps. Low and high pressure.

I would check injectors and the pump(s) pressure on cold start using a Star to check the live data. There are many causes for non start, most are caused by lack of fuel pressure for whatever reason.

The glow plug control unit is also a very common cause of a poor start on the V6 diesel. You have changed this though.

 

[stevowozz43]

Thanks for the quick reply.Had a star check last week and came back with live data showing no pressure issues and electronicly the injector were fine. Is there a manual test for the pumps? Also many threads talk about air leaks and o rings, is that a possibility with this engine?