Hmmmm, after reading some posts, I have a question about my 83 300 SD glow plug system.
I have the later model AFTERGLOW timer/relay, and to my understanding I should not get the FULL burn when my engine is hot.
When starting my car cold or hot, the plugs run for a very long time. This does not bother me on the cold starts but on the hot?
I run through a LOT of glow plugs, I mean every month or so I have to replace them. I have a hunch they are running when they shouldn't be.
I have changed engines (not for this reason ), and the problem continues. I have replaced the timer unit and the problem continues. What gives? Is there a broken signal wire? a bad temperature sending unit? I do not have the diagram for this system. Where does the signal come from? I am tired of buying so many damn glow plugs! It is especially bad when I discover 2 have suddenly burned out on one of those -40 F mornings.
Should I find a new harness?
I haven't driven the car in months, but with the interior restoration completion date coming soon along with another summit county winter I would like to resolve this problem. (Did I mention I am tired of laying down 50 bucks every month? )

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

Breckman99,

GP should usually last 10 to 20 years in your engine. You might be using the wrong GP for the GP relay you have. The regular GP for that engine were designed to shut off when the starter is energized, thus they are not glowing long after the engine starts.

Check with Bosch to see if special GP are available with the after start glow GP relay you are using.

How do you keep the fuel from congealing on a -40*F morning? You must keep it a heated garage overnight but how do you keep it warm when its outside during the day in the cold weather?

P E H

I have been using the same glow plugs that are specified for the 617 engine. If anyone has a diagram I can probably fix it, I just didn't want to spend all the time tracing where all the wires go! The main problem is every time I start it hot (which can be allot of the time) the plugs run for up to three minutes!! The power of the engine is not good when the plugs are on. when I bought the relay kit it came with the plugs - which were no different from the ones I usually buy anyway.

To keep my fuel a liquid I usually run a additive in the winter, and no it does stay outside. It stays plugged in, and on those real cold nights I run a small electric heater inside the car. The only time I have ever had a problem is when the plugs go out (too often) and when my block heater fried. Where I work I have heated underground parking, so there is no issue there. My work is also about a 2 minute walk to the ski lift, so I usually never park outside except at night where I can plug in and small stops at stores.

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

For the W123 617 engine.

http://skinnerbox.steaky.org/Service/W123/Index/617T/15EngineElec.htm

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

After reading the information provided, it seems my car has a temprature sensor built into the relay itself!!! So this means if it is cold outside, no matter the engine temprature the plugs will operate. WHAT??? I do not like this feature one bit! I think bosch decided they needed to sell more plugs! Also intresting is I can not buy the original relay, only the "afterglow" type! Another indication Bosch needed more glow plug business~!
I think I will be looking into building circut tied into the coolant temprature that will cut the system completely when above a certan point! Nothing is wrong with my system! how unfortuinate!

BOSCH

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

What? must be a bad day! my pukeface didn't work right either! BLAST!

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

Go back to stock OEM glow plug relay; with the block heater and heated garage, you do not need the modification...

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Yes exactly, but where can I find the original relay? (not the superseded part from bosch) Everybody stocks the afterglow unit as the replacement, that’s why I ended up with the damn thing....

__________________
1983 Mercedes 300SD
1987 Mercedes 300SDL
2001 VW Passat 2.8 AWD
2007 OM642 Jeep WK 4x4

Or check out this handy little thread I have been contribuiting schematics too
Go to the end and have a looksee...

Violet Wire and Modifications

Try ebay.com

and

Read this thread.
http://www.peachparts.com/shopforum/showthread.php?t=107338