9-5 tdi 2.2 Cold start, no glow plug light problem

[jaydarcy]

Hi I really could do with someones expert advice and guidance.

I have a 9-5 2.2 tdi 04 reg vector 157,000 miles, regular service history it has the following problem;

I have had the car now for 3 years and have never seen the glow plug light on the dashboard ( I presumed it was a new generation diesel that didnt have a glow plug light on the dash ) and the car has always been a bit of a pig in the cold weather to start.

When car is hot or the weather is nice and warm starts a treat, when car has been standing overnight in this cold weather it can take a good 5-6 seconds to start followed by a large white cloud of smoke, car runs fine on the whole just a bugger to start in cold weather. When the car starts from hot or in normal temp weather no smoke or any other problem.

I have replaced all 4 glow plugs, drain back pipes, fuel filter housing, problem still exists.

I decided to disconnect the plug to the water temp sensor on the top of the engine and hey presto the glow plug light came on !
Next time I went to start the car from cold I decided to remove the plug from the sensor and the glow plug light came on and the car started within a heart beat.

So this led me to shoot off and buy a replacement sensor, which I swiftly fitted and hey presto next the next morning NO glow plug light and its a pig to start again.

I thought I may have got hold of a duff replacement, but I think it does work as it appears to also control the engine temp display on the dash board.

So in summary.

No glow plug light and a bugger to start in cold weather, when plug is removed from water temp sensor glow plug light comes on and car starts very well but temp sensor on dash does not.

Can anyone shed some light on this for me ?

 

[pgarner]

hey and welcome to the site mate


dont know saabs but is there any additional glow plugs in the engine ? - i know some engines have them in the coolant pipes to help speed up the heating of the engine.

 

[jaydarcy]

I have been led to believe that there are no other glow plugs other than the four on top of the engine that warm the pots on start up. I can only think that whatever recieves the signal from the water temp stat for the glow plugs to become live isnt getting the correct resistance reading, as the cabling appears to be ok as the dash board temp display works correctly.
Thanks Jay.