w115 glowplug system? - PeachParts Mercedes-Benz Forum

Monomer · #1 03-16-2008, 10:14 AM

It's a new to me car. It has a 617 with the old style loops glowplugs. I should have checked before I ordered new plugs, I would have ordered a retrofit kit for the newer pencil style.

It's got 5 new loop style plugs.Dummy light still does not work. How often do these plugs come bad from the factory? Where's the relay and fuse located for this system?

HighDesert Benz · #2 03-16-2008, 10:43 AM

The relay is under the dash on the left side of the sterring column. It's an aluminum box about 1" x 3". Can't remember where the fuse is at the moment or if it has one. Try checking that the wire coming off the #1 glowplug has a good connection to the big round sensor between #1 & #2 glow plug. If it doesn't the light will not come on. I'd say the chance of all the plugs being bad from the mfgr are very low. Good luck.

pizzachef · #3 03-16-2008, 12:11 PM

Is it recommended to convert to the newer style plugs? Is there much to the conversion?

kerry · #4 03-16-2008, 01:05 PM

Quote:

Originally Posted by pizzachef

Is it recommended to convert to the newer style plugs? Is there much to the conversion?

Absolutely. Conversion is simple. Remove old plugs, throw away ground wire and wavy heavy wires. Install new retrofit pencil plugs. Put original hot wire to first plug and install jumper wires to each of the rest of the plugs.
Whole kit includes a new relay and jumper wires. I see no need for a new relay so I think it's better to just buy the plugs individually and make up 3 or 4 short jumper wires.

You get faster hotter glows with pencil plugs and no wasted heat escaping to atmosphere via the heavy resistance wires.

HighDesert Benz · #5 03-16-2008, 01:52 PM

Quote:

Originally Posted by kerry

Absolutely. Conversion is simple. Remove old plugs, throw away ground wire and wavy heavy wires. Install new retrofit pencil plugs. Put original hot wire to first plug and install jumper wires to each of the rest of the plugs.
Whole kit includes a new relay and jumper wires. I see no need for a new relay so I think it's better to just buy the plugs individually and make up 3 or 4 short jumper wires.

You get faster hotter glows with pencil plugs and no wasted heat escaping to atmosphere via the heavy resistance wires.

Completely agree. I've done all of mine. Just take the grond wire off the last plug and tie it back out of the way, leaving it disconnected. It isn't needed on pencil type plugs. I didn't use a new relay on mine either, just new plugs & jumper wires.

pizzachef · #6 03-16-2008, 02:00 PM

Excellent...when I bring home the 115, this will be one of the first enhancements.

Monomer · #7 03-16-2008, 02:12 PM

Quote:

Originally Posted by HighDesert Benz

The relay is under the dash on the left side of the sterring column. It's an aluminum box about 1" x 3". Can't remember where the fuse is at the moment or if it has one. Try checking that the wire coming off the #1 glowplug has a good connection to the big round sensor between #1 & #2 glow plug. If it doesn't the light will not come on. I'd say the chance of all the plugs being bad from the mfgr are very low. Good luck.

thankyou.

the large round sensor, what is it? - it dosnt look to be in the best of shape.

Also, I see you have a w115 for parts? what color interior and does it have a passenger side mirror?

HighDesert Benz · #8 03-16-2008, 02:51 PM

the big round sensor is the temp sensor for the GP relay.

The interior I have is light brown, has all the door panels, B pillar and rear seat cover. Front seat covers are gone. Sorry, no right side mirror.

Monomer · #9 03-16-2008, 03:01 PM

Quote:

Originally Posted by HighDesert Benz

the big round sensor is the temp sensor for the GP relay.

The interior I have is light brown, has all the door panels, B pillar and rear seat cover. Front seat covers are gone. Sorry, no right side mirror.

looking for the drivers side door pocket.

this car is an olive green, I should be able to change it's color, correct?

coolerelmo · #10 03-16-2008, 04:20 PM

I heard that by doing the conversion to the pencil type, that they don't last has long has the old style. Is this true? Is there a big difference between the two?

HighDesert Benz · #11 03-17-2008, 05:31 PM

Quote:

Originally Posted by Monomer

looking for the drivers side door pocket.

this car is an olive green, I should be able to change it's color, correct?

A decent brand of vinyl paint should work for the map pocket but I haven't tried it to be sure. Or are you refering to changing the entire interior color?
I looked around my stuff and the only spare map pocket I have is a tan one with a 1" chunk missing on the top edge. Those darn things sure are fragile.

diametricalbenz · #12 03-16-2008, 08:48 PM

Quote:

Originally Posted by HighDesert Benz

the big round sensor is the temp sensor for the GP relay. (

The new GP relay has a temp sensor or the W115 itself has one? The W115 is all manual so a temp sensor would be a moot point.

HighDesert Benz · #13 03-16-2008, 11:15 PM

Quote:

Originally Posted by diametricalbenz

The new GP relay has a temp sensor or the W115 itself has one? The W115 is all manual so a temp sensor would be a moot point.

actually the W115 300D was automatic used the same type of relay as the early 123s. I didn't know it until I bought one, I was expecting the gorilla knob like my 240. The GP light is at the base of the speedo.

pdxwaker · #14 03-17-2008, 01:31 PM

Quote:

Originally Posted by Monomer

Dummy light still does not work.

Are you talking about the 'salt shaker'? There are quite a few variations of W115 glow plug systems... some with relays, some without. Do you have a gorilla knob for starting? We really need more info on the car to help you out.

I've had several W115 220d's with salt-shaker indicators and no glow plug relay (gorilla knob). The salt shaker doesn't glow real brightly and it takes ~45 seconds to get even a faint glow. When I first got the car(s), I thought this indicated glow plug problems. However, after a lot of troubleshooting (including glow plug current measurements), I found that the indicator didn't affect or indicate proper glow plug operation. When I upgraded to parallel plugs, I bypassed (i.e. shorted) the salt shaker indicator.

Monomer · #15 03-17-2008, 04:03 PM

It's an 1976 155.114

"240D 3.0"

It uses those huge, loop plugs. It has the big thermo switch over by the plugs mounted in the head. the plugs are connected in a series, with ceramic bushings in between the wires. It has NO gorilla knob, and the typical GP light on the inside.

When checking the wiring with an ohm meter (on diode mode, beeping whenever a connection is present) I get a beep just about no matter where I touch the probes. end of the screw on the GP to ground gets a signal, glowplug to glowplug gets a signal (this is with the car completely off) When you set the key to the glow position, I get a little smoke from the GPs, and a reading of .5 VDC from ground to glow plug's screw.

Anyone have a diagram of this system; the russian EPC site lacks anything on the GP system, I'd at least like to see if everything is in it's correct place (I tried my best, I even took a bunch on pics before disassembly; but it's easy to overlook a small detail.)