92 300D 2.5 glow plug/start issue, need advice

[klipweld]

I need some advice, I just picked up a nice looking 92 300d. The guy sold it because it wouldn't start for him and made him late ! Then it just sat. My buddy and I started it with start fluid and I drove it home ! The closer i got to home the better it ran. The fuel at filters and exhaust smelled funny. I drained all fuel out and refueled with fresh fuel and new filters. It runs smooth as ever now, AFTER it starts. The fuel was dark, like blackish, I have heard of diesel alge ? Now I need to work on glow plug system so it will start. The glow plug light in dash will not come on untill the system has had like enough time to run the glow plugs, then comes on ? Have you ran across this with your 2.5 ? Does this sound like the glow plug controller/relay ? Would you just change all glow plugs? ( witch looks like a lot of fun ) It looks like the intake will have to come off to change them. I don,t have any books for car yet. Thanks for any help. I know evry one wants to see pictures as I do when I read post's. I will try to take some pic's of my new and other 2 MB projects, 83 240D, engine swap,driving, and 77 300D, rust surgery. Thanks again, Charlie Klippel

[Jetmugg]

First thing to do is to check the glowplugs individually. Check the resistance first, but that is not a slam-dunk confirmation of goodness. It is a slam-dunk confirmation of badness, if they are "open" - (i.e. show no resistance)

Then check them with an electrical load. If they show a good resistance and will take a load, then they are good.

You can check voltage from the relay at the connector plug. This should be pretty easy to confirm. Turn the ignition switch to the run position, and check each circuit with a voltmeter.

If you have to change the glow plugs, yes, you should remove the intake.

SteveM

[tbomachines]

Changing the glow plugs is always a good thing to do when you first pick up a car, along with the filters and fluids, etc. You might as well change them out for new Bosch plugs while you're hunting for a problem...ream the holes too.

[amg280]

I would put 5 new BOSCH glowplugs in, regardless. I just did this on mine. Its not a big job, I think it took me about 2 hours, with pulling the intake. Do yourself a favor and get a new intake manifold gasket (mine was leaking anyways), and new fuel line clips (they get brittle and break).

Chances are the glow plug light will come back to life, or you have a fuse/relay problem.

[klipweld]

I just got meter readings , looks I will be getting a set of glow plugs. 3 dead glow plugs, other reading 1.55 and 2.73 OHM's on 20K setting. With the plug off controller going to glow plugs, I was getting 12 volt power there at the 5 pins. So that would indicate JUST the glow plugs need replaced, right?

[Jetmugg]

With 3 out of 5 dead plugs, you will definitely notice an improvement when you replace them. It sounds like the relay and harness is correct, just need some new glow plugs.


Replace and enjoy.

SteveM

[Diesel911]

When the Glow Plugs use a Glow Plug Reamer to ream the Carbon out of ht Glow Plug holes or us an alternative metnod to clean the Carbon out. There is several Threads on various ways to do that.
Before installing them put some Never-Seeze type compound on the Glow Plug threaded area.