mbenz,

Do you have series or parallel GP? Series GP have a wire loop on the business end and Parallel GP have round rod on the business end. If you have series GP, just one of them may have been bad.

You terminology was part of the problem I had understanding what your malfunction was. Things such as it cranked but would not turn over. What does that mean? Do you mean the starter cranked the engine but it would not fire? I had juice to the relay. WHat does that mean. Oranges have juice but not electrical circuits. You said you have power to the relay. How do you know that unless you have a wattmeter or measured the current and voltage.

Things like above make diagnosing problems on line very difficult. Please try to learn the correct terminology and use it.

I was going to warn you not to buy a new GP relay because I didn't think your old one was NG, but it was too late. You already bought one.

P E H

rderton,

Did you get your car started yet?

P E H

The problem is always to find an ammeter that would do the job.

A proper ammeter that can handle 15 amps DC is not readily available, in most cases.

Again, just replacing the glow plugs worked perfectly.
It is a wonderful academic subject to test the plugs and everything.

But, thread after thread, have shown that the fastest and most reliable way to fix glow plug issues with the 123 MBs is to just buy new plugs, all 5, and put them in.

Mark

__________________
1983 300CD 245K
Running WVO blends

............................. Don't let PEH see this.

P E H
I'm going to push mine into the garage this weekend and take it apart. We got my old Ranger back for my youngest son and I have been driving that for awhile, so my 300D is off the insurance until June when he gets his license.

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

Well if you need any help, let me know. Ill be heading back from Dallas on Saturday night and will be comming down 35 through Round Rock and would be glad to assist if you need the help.

__________________
1980 300D European
"The Red Fox"
200,000 miles

2003 Chevrolet Silverado

609 Certification

Car started. Wonderful smoke after sitting for 5 months, no bugs left in our neighborhood. When my 16 year old gets his liscense next month I'll get it back on the road.
5 out of 5 glowplugs were bad. The relay wasn't giving any indication, so I guess it should go on the list of parts to replace.

mbenzgoodyear thanks for the help offer but I was cutting limbs yesterday.

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

rderton,

Did you test the GP individully across the battery? Its hard for me to believe all the GP went bad at once.

The GP relay may be OK. Disconnect one GP and see if the dash light blinks after you start the engine.

I wouldn't replace a GP relay just because it doesn't indicate an open GP. I can tell when a GP is open by how the engine runs after it starts. If it missfires and then all of sudden runs OK, its probably an open GP.

P E H

I checked each glow plug as I pulled it out. They were all dead, 3 of them had a good coating of oil. I also checked the new plugs. Replacing the relay is far down my to do list.

__________________
84 300D 251K
87 190DT 281K - Sold
06 Ford Escape 172K
94 Ford Ranger 250K
99 Chevy Suburban 181K

rderton,

Did you do the one GP disconnected test to see if the GP relay causes the dash GP light to blink after the engine is started?

I still can't understand how all the GP were dead. Only once in 35 years did I have more than 1 GP dead at one time. But I change a GP as soon as I determine it is dead.

P E H

Stuff a big towel next to the engine when swapping out the glow plugs. Allows you to drop bits and pieces without losing them. Believe it or not, this technique keeps you calm and peaceful while working on the car. Nice to have one less thing to worry about.