Hey all,

When I turn the key to the glow position, the dash glow plug indicator light does not come on. If it let the car sit for the whole 30 second glowing cycle, I do hear the click and the car will start, although it will be a little rough. After the car is started, then the glow indicator light comes on and stays on for about a minute then goes off.

Feels when the engine starts rough kinda like it didn't glow warm enough or maybe one cylinder isn't as warm as the others...

I do have a set of new glow plugs I haven't put in yet--haven't found the magical way to replace with without taking all the upper tubing off.

Any testing that I can do, or recommendations? Not sure if it's a relay problem either....

Thanks!

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

I'd recommend testing the individual glow plugs. You can get a lot of information with a very cheap ohm meter. And a higher quality of information with a $20 multimeter that includes a 20-amp current test capability.

Glow plugs should read about .5 to 1 ohm resistance. Blown glow plugs will show an open circuit. And, glow plugs should pull something in the range of 12-15 amps or so after "settling down" from the initial current inrush. Weak glow plugs might pull 5 amps.

So, the ohm meter test lets you find blown glow plugs. With some interpretation (higher resistance) you might find weak glow plugs. The amperage test lets you conclusively find weak glow plugs.

There is a connector on the glow plug relay that you can pull off to get access to the wires that go individually to each glow plug. From that point you can easily test each glow plug.

Lots of information in the Forum about glow plug testing - a search will reveal a lot of reading material.

Ken300D

P.S. Your symptoms indicate several bad glow plugs as the most likely diagnosis.

__________________
--------------------------
1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Hey,

My local MB dealer is quoting me $450 parts and labor to change the plugs. Doesn't seem to bad, but I don't have another place I trust to do the job. Too high?

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

invisic,

I think $450 is outrageous to exhange the GP but I have only done it on 617 type engines, where the only thing you have to remove other than the GP is the GP wire.

I would suggest that before you spend that much money, you should do the GP tests described in the previous post. Probably only one of the GP is bad and replacing all the GP because one is bad is a waste of money (and GP). Can't you DIY and save the labor cost? Where else can you ake $70+ an hour tax free?

P E H

It seems virtually impossible to get at the plugs on this car. I changed them on my 1980 300D and it was a breeze. You got the intake piping and fuel lines and all kinds of stuff in the way.

Top/front view


Right side view


Should I brave removing the intake piping and other associated items? I'll do some searching for pointers on this on the system here.

Thanks for any other info or opinions. Yes, I have better ways to spend my money.

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

After some searching, seems the general consensus is to remote the intake manifold and go at it from there. I'll review removing that and possibly do some de-greasing before starting.

Could probably use a pep talk as well. :/

Thanks for the info.

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

invisik,

Before you remove anything, test the GP for resistance and even better, current. You can do this thru the connector on the GP cable that plugs in to GP relay with out removing anything else. You might not have to remove as much as you think and if all the GP are OK, you wouldn't have to remove anything.

Of course Murphy's Law says that if you have one bad GP, it will be in the worst possible location to R&R.

I see what you mean by the pictures that your GP are nothing to R&R like the ones are on the older 617 type engines. Sometimes older is better.

P E H

I located the glow plug relay, so I will open it up and do the testing this afternoon when I get back from an appointment. I have a multimeter.

Yes, I agree older is better in this case. Like I said before, my 1980 was a dream to change, took all of about a half-hour. In an older thread, I saw a picture someone posted of the 99 E300 intake manifold--what a bear that must be. So I feel a little better about what I have.

I've look at those and post back later....

Thanks!

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

Regarding the E300 intake removal...

I am not proud of the fact that I have had to remove mine so often (GP's, fuel lines, flapper valves). However, I can say that it could be removed in less than 30 minutes without trouble.

__________________
1996 (W210) E300D 86K - Traded in for a Lexus
1992 (W124) 300D 2.5 Turbo 202K - Sold
1983 (W123) 300D, 146K - Sold
1970 280S, 263K - Sold - Beginning of addiction

invisik,

If your relay is similar to the one on a 300SD, you don't have to open it up. There should be 2 connectors on the side of the GP relay. The larger one is the GP cable. Just remove this connector and you can probe into the holes in the connector. If you have bananna plug test cables, they will plug into the holes for a good connection.

P E H

The 606 intake is a breeze compared to the 602/603. The only really hard thing about the 602 intake manifold is the 3 6MM allen bolts on the outside of intake runners, they are very hard to get to and are prone to being dropped.

A 1/4 swivel 6mm socket taped to a cut-down 6mm allen wrench is the best way I've found to get them.

Ok, so I found the larger plug and it has 5 leads on it, one for each gp. Ok, good.

So, I probed them incrementally.

1 and 2: OL
2 and 3: OL
3 and 4: .8 or .9, went back and forth
4 and 5: OL
5 and 1: OL

My multimeter is the Radio Shack 22-163, if anyone's wondering.

So, do I have just one good glow plug?

Thanks again!

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

Using an ohm-meter (resistance) test, you test each glow plug's resistance to GROUND. So, find a good ground point on the car's frame, and then get the resistance reading on each glow plug lead.

You seem to be testing resistance from glow plug to glow plug - wrong method.

That said, there does seem to be a problem indicated with the readings on your test - you might have a shorted glow plug. But a shorted glow plug should / could blow the strip fuse in the glow plug relay.

So, test each glow plug (and make sure you understand which pins go to the glow plugs first) to ground and report back.

Ken300D

__________________
--------------------------
1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

invisik,

WHat do you mean by 1 and 2, 2 and 3 ETC? To measuse the GP resistance you connect one lead of the ohmeter to a good ground and the other lead to one of the holes in the connector. If you connector has 8 holes, only 3 are connected to GP. The other 3 may have no connection or may be connected to a temperature sensor.

You have to find the 5 connector holes that are connected to the GP. Mine are connected to the GP in an "L" shape: 4 along one side and 1 other corner. If you can get to the GP, you can find which is which by connecting one lead to a GP terminal and probe the connector for continunity. Write the GP # and the marked hole number so if you find a bad GP, you know which one it is.

P E H

Ok, I wasn't aware I had to probe one end to the ground. I put the postive probe in the socket labelled "1" and the negative probe in the socket labelled "2" and took reading (and so on through 5).

So, should I put the negative probe to ground, or does it matter which one on the multimeter?

The car is at the grocery store right now I'll check them to ground when it gets back.

Thanks....

-m

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC