How do you know the glow plugs are not staying on long enough ? They dont need to be on long. How cold and how long ?
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I have a very nice multimeter.....
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hm
Sorry to be slow in replying; having an ongoing [8-week] "new phoneline" nightmare! Broadband activation just took the whole line out for two days....
The coolant sensor affects the length of glow-plug operation; but I find the commonest cause of poor cold starting on non-PD TDi's [with working glow-plugs] is incorrect pump timing. If the plugs are on for more than around five seconds, then that's probably enough for them to reach full temperature.
Have you measured the pre-start glow period - with and without the coolant sensor connected? Are all the glow-plugs servicable? As you had the means to determine that the plugs are going off with the light, do you have a basic multimeter to check individual plug resistance? [Or a laser thermometer?]
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screwloose,
I have not had time to look at the car......the plugs stay on for about 4/5seconds, but the car is still very lumpy at starting.
She has brand new Bosch Datrumn Plugs fitted...I have used these on many cars and swear by them.
How easy is it to alter the pump timing....is running the incorrect timing dangerous for the car? how do I check with VAG?
Thanks
H
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hm
If the plugs are new and you have doubts about the pre-glow duration; then try heating the plugs twice before starting and see if that makes any improvement.
I know VAG-Com can check pump timing; but as it's not a program that I've personally used for the purpose, consult the manual for exact details. Altering the pump timing is done by loosening the 3 pump-to-cambelt-pulley bolts and experimenting with settings until a perfect reading is obtained. The electronic timing is extremely precise and even if it's slightly wrong, I've never seen it cause any harmful effects.
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Please don't start fiddling with the pump timing if you don't what you are doing. You can do a lot of damage to an expensive pump. These are very precise bits of kit!
Why would the pump timing suddenly be out? Unless it has been played with or something has come loose it is not likely to be this. The glowplug duration is taken care of by the ECU with the coolant temp. sensor being one of the inputs.
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\"Nothing less than 8 cylinders will do\"
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V8 man
Electronic timing on these [and many other diesel VAG models] is merely a cam-belt pulley adjustment. It doesn't involve touching the pump at all. It should always be checked after replacing the belt, as mechanical [locking pin] setting isn't accurate enough for these engines.
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