This summer I checked the glow plugs on Fritz and all checked OK. Last Thursday when I left work, the glow light didn't come on until after the engine was running. It has started to get colder and the light comes on later after the engine is running. The day this happened, it was really humid/foggy. I was planning on changing the glow plugs this spring, but that might happen sooner.
Could this be a problem in the afterglow system, I don't have a real good feel for this, but could it be reset by disconnecting the battery for a while?
When he starts, the idle is rough like no GP for about 30 seconds, then smooths out. This is in 25-30 degree temps. I would think the light wouldn't come on at all if the circut was bad.
Thanks

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Habits I support
95 E300 D 220,000 & counting (I think I'll call him Fritz)
02 Tahoe (Momma's ride)
98 GMC Sierra 120,000
57 Chevy Nomad (bought in '69)

There is a lot of glow plug trouble shooting threads and DIY threads and at the "Diesel Giant" (he is also a member) he has excellent pictures and instructions that will walk you through the check.
http://www.dieselgiant.com/glowplugrepair.htm
From all of the threads I have read you should suspect a problem with no good glow plug/s but also take quick close look at the 80 amp fuse on the glow plug relay. The relays are usually OK.
If you do not have a electrical test meter (multimeter,VOM voltage ohm meter) they are cheap and can be had at Harbor freight for as little as $2.50 when on sale and around $5-$!0 when not on sale.
Don't for get to let us know how thing came out!!!

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84 300D, 82 Volvo 244Gl Diesel

Diesel911
Thanks for the link. When I checked mine, I had the intake off. Looks like I should have changed them when I had it off.
Thanks again

__________________
Habits I support
95 E300 D 220,000 & counting (I think I'll call him Fritz)
02 Tahoe (Momma's ride)
98 GMC Sierra 120,000
57 Chevy Nomad (bought in '69)

Yes, at the Diesel Giant sight the engine is different and you do not need to pull the manifold off to remove them. In Diesel Giant’s instructions I believe he had at least 1 bad glow plug and had to remove it; you may not have any bad ones. (also I believe that you glow plugs are longer.)
But you do not need to even see the glow plugs to test them through their wires (a good idea any way as this helps eliminate the wires as a cause of a problem) if you pull out the connector out of the glow plug relay as Diesel Giant did. This way you are not removing the manifold just to test the glow plugs.
If you find you have a problem with the glow plug/s you would probably need to remove the manifold to get at them.

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84 300D, 82 Volvo 244Gl Diesel