glow plugs
 

I need some help. I'm new at diesels. My daughter has a 1981 240 D. The glow plug light has stopped coming on. I put a test light to the glow plugs and there is no power until the key is turned to the start position. I checked the glow plug controler and it shows power to the red wire in the run mode. The ground test good. The fuse is good and the controler has power.
The glow plugs, at least some are working because the car still start even when very cold.
Any ideas would be helpful.
Thank You

Mark Theofanides

On my 1982 240D the glow plug light quits when one plug goes bad. It doesn't start very well when this happens. I just changed them all a few weeks ago after the light stopped coming on and it was getting hard to start.

Yoy might have one or more bad GP.
If you live in CA and if temp are not very cold, you might not see the big difference in the morning start. Here in NY even a weak or failing plug on a cold day will give you a very bad shake upon a cold start for about 2-3 minutes. I think its a GP. A quick but less reliable test method was posted by me on this forum. Check the MVK post. Hope this helps.

http://www.peachparts.com/shopforum/showthread.php?threadid=48751&highlight=test+glow+plug

MVK

By the way welcome to the Family.

Put one ohmmeter lead on the base of each glow plug and the other at the extreme end where it is connected to wire. You should have an ohm or less there - it needs to conduct a lot of current:eek:

glow plug relay
 

thank you for the help. tested plug and all are good. intesting found that the relay only lite the glow plug when the stater is used. has anybody take the relay apart.

Thank you
Mark Theo

M.Theo,

Your problem could be a bad connection from the key switch or a bad key switch itself. It could be a bad connection between the connector and the GP relay. This is the smaller of the 2 connectors on tha relay. You should have 12 volts to the GP relay when the key is turned to the run position, when the engine is not running, and the relay should click and energize the GP.

P E H