I'm doing the violet wire glow plug relay mod and found two purple wires attached to the relay. This is a 78 so it's the type of relay under the steering column. Which one should I disconnect? The fat purple one with the white stripe or the thin purple one? Thanks!

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IIRC, I read it was the thin purple one. Do a search first. I believe Forced Induction posted a how to on this.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Dont cut any of them anyways. Just pull it out and tape it to the bundle. No need to cut in case you want to go back.

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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Yeah, I'm going to just pull and tape it, but want to make sure I'm doing the right one. I've done lots of searches and I can't find any mention of anyone else having two purple wires. I guess I could try pulling each one out and just see what happens.

Should be the second one from the bottom right in your picture.

Thanks! I will give it a shot.

The easy way to tell would be to use a test light or voltmeter and crank the engine. If its right, it should only light when the starter is used.

The heavy wires are power to the glow plugs. The thin wire is the one to remove and tape to the cable.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Well I removed the thin purple wire and it seems to have helped a bit. It used to rumble and shut off if I didn't rev the pedal. It still rumbles, but didn't shut off at least and i didn't hit the pedal. We'll see what happens when it's colder out. I think some new nozzles will be my next move. Thanks for the help.

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1980 300D, 128K

Have you determined that all of your glow plugs are in good condition?

They are new Bosch duraterm glow plugs, just installed about 500 miles ago so they should be good. I've also recently done a valve adjustment, new fuel filters, new air filter, oil and filter change. Each thing seems to make it a little better. When I did a diesel purge, the engine ran very quietly for a few days, but then back to rough starts and pinging. When I get a chance I am going to get new monark nozzles from C Sean Watts. And I'll try to test the compression when the injectors are out to see where I stand.

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1980 300D, 128K

What does this mod do? Cause the standard style GP Relay to run the full 40ish second glow every time you start?

On mine the afterglow relay always runs them about 2.5-3 mins after I start....

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'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Yes. It will run until it times out as if the starter was never used.

Where would you find this relay on an 83 300SD? Thanks.

on an 85 300sd... on the relay their is two pluged in harness's. Is the purple wire mod a removed wire from the large harness (has individual GP wires) or a mod to the smaller plugged harness with the smaller wires.

Thanx in advance.

This mod also "requires" pencil style plugs or will it work with the others they just will not last as long?

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The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels