C250 TD glow plug issues

[swampea]

Hi,

Recently the glow plug light in my car would stay on for about a minute after the car was started.

At the same time, with the mornings getting colder the car has started taking a long time to start from cold.

To get it started i would have to crank it 3 or 4 times at 10-20 secs a time.

The car is a 1997, 160,000 miles and has had an oil and filter change.

Today i changed all the glow plugs, but on a warm engine, the car started fine, but the glow plug light still stays on.

Tomorrow i'll try to start it from cold to see what happens, but in the meanwhile if anyone could hint at what else to investigate i would be very greatful.
thanks.

 

[SilverSaloon]

Hi,

Recently the glow plug light in my car would stay on for about a minute after the car was started.

At the same time, with the mornings getting colder the car has started taking a long time to start from cold.

To get it started i would have to crank it 3 or 4 times at 10-20 secs a time.

The car is a 1997, 160,000 miles and has had an oil and filter change.

Today i changed all the glow plugs, but on a warm engine, the car started fine, but the glow plug light still stays on.

Tomorrow i'll try to start it from cold to see what happens, but in the meanwhile if anyone could hint at what else to investigate i would be very greatful.
thanks.

Have you checked all the fuses for the glow plug warmup?

Replacing them when engine is warm is fine (makes it easier to change them)

I reckon a new glowplug is a dud?

or there is a problem with the glowplug control unit. I read that there may be a fuse inside this on some models... maybe its broke?

EDIT - you are looking for something like in the link HERE

 

[swampea]

Thanks for the reply SilverSaloon.

I checked all the fuses and they are fine.

I'm finding it hard to believe that a new plug could be a dud, but how do you test them?

I also checked all the wiring and it seems to be intact.

When i took the old plugs out, plug 5, nearest to cockpit was a mare to get out and had massive carbon build up on it. the rest seemed ok. is there a way of testing which plug isnt working? and on that note is there an easy test to see if i'm running on all 5 pots? i'm pretty new to diesels so dont really know.

thanks

 

[swampea]

oh, just found your link. i'll do those tests tommorow and see what turns up..

 

[Dieselman]

I doubt the new plugs are duff. The glowplug light will stay on for a few cycles after changing the plugs but should then work as normal. It sounds like the relay may be duff along with No5 plug.

The best way to test is to connect the plug upt 12v when not installed intot eh engine.
Use a meter or test lamp to check for 12v presence at the plugs when called for.

 

[swampea]

Started from cold first time today, glow plug light goes out straight away, so looks like problem solved ( fingers crossed). i'm just waiting for minus temperatures again to test it properly.

Thanks for the tips.