Just recently my V6 diesel has developed a fault when starting from warm. It takes a long time (10-15 seconds) for the glowplug light to go out and then it starts only after a bit of churning (maybe 3 seconds or so). It immediately starts with a very high tickover speed (1200-1300 rpm). This reduces down to below 1000rpm after about 15-20 seconds so can then drive away. Cold starts are fine, starts after glowplug light goes out (2-5 seconds), 1 second on the starter and starts immediately ticking over at about 1000 rpm. Hot starts usually okay but don't usually wait for glowplug light to go out, ticks over at about 750 rpm.

Feels like a temperature sensor maybe faulty but I've no idea where this might be found. Had a new injection pump (ouch!) a couple of years ago but has been running perfectly until now.

Any ideas?
Paul

From the description sounds like the G62 coolant temperature sensor...

 

You should scan it with the VCDS first and check any stored errors, but if that is unavailable, you could check if any errors are displayed in the Climatronic codes menu (accessible pressing ECON+TEMP down+Fan down - Google it), for a faulty sensor. 

 

Location becomes quite straight forward as soon as you lift the engine cover, somewhere in the "V", close to the VP44.

Thankyou so much for your swift reply, I shall take a look at what you suggest in the next day or two. One further thought, I think there is also an oil temperature sensor (G8?), might this also cause a problem?

Regards, Paul

That is the oil level sensor and if something would have been wrong with it, you should have had an error displayed on your BC.

Don't think it's related to your issue...

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I had a similar issue. New CTS fixed it as suggested above. My last one was made by Topran. Can recommend. Still lasts. The previous one failed in a couple of months. Get Topran or OEM. Have a bit of distilled water or G12 ready to top up after the inevitable loss upon removal.

Replaced CTS but unfortunately didn't make any difference, still the high tickover speed when warm. Will try and find someone with VCDS to see if that flags up a fault.

Hi, final post about this problem. Recently had car serviced by an independant with VCDS equivalent which flagged that the oil temperature sensor was intermitent (G8). This was replaced and no further problems with the high tickover, glowplug light goes out more quickly and it doesn't take so much churning on the starter before it fires. Job done. thanks to all for comments.

On 22/11/2016 at 15:10, milespd said:

Hi, final post about this problem. Recently had car serviced by an independant with VCDS equivalent which flagged that the oil temperature sensor was intermitent (G8). This was replaced and no further problems with the high tickover, glowplug light goes out more quickly and it doesn't take so much churning on the starter before it fires. Job done. thanks to all for comments.

 

Sorry to be a pain, did you happen to see where the sensor was fitted? I've bought one to hopefully resolve the same issue but can't find the sensor location!

 

Jack.

Hi Jack, didn't see exactly where it was fitted but from the parts diagram it looks as if it fits somewhere close to the oil filter which sits in the "V" of the engine, behind the fuel pump I think. Hope this helps, it solved my problem for sure. Regards Paul