This car does not like me apparently.

On sunday, I changed 3 of the 5 glow plugs on my 79 300D, and it went from not running to running fine!

Then on Tuesday, the car failed to start again. No problem, I figured. I went ahead and changed the 2 other remaining glow plugs without pulling the injector lines yesterday evening.

Now, the car will not only not start, but after the second time I attempted to crank, the glow plug idiot light fails to light up now. I let it sit and got back to it tonight after work, and the light still fails to light up.

Am I screwing something up here?

Check the GP relay fuse. Also, it would be a good time to upgrade to the pencil type, if you still have the loop style gp's.

__________________
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

Thanks. Would the GP relay fuse be inside the fuse box, or is it a seperate setup?

If your glow plug relay is inside the engine compartment above the driver side wheel well the fuse is in there. If your Glow Plug relay is under your instrument cluster I believe the fuse is in a seperate plastic box on the firewall.
Take a look at the site (free manual) and go to: 15-Electrical System Engine (Preglow)

http://www.pauldrayton.com/uploadfiles/merc/Service/W123/Index/617Nindex.html

__________________
84 300D, 82 Volvo 244Gl Diesel

Hmm.. I see the box in the picture where the wire from the backside glow plug goes, but there is no cover for the box. And hard to tell how a fuse goes into it. This is the same German-style fuse found in the regular fusebox correct?

Thank you so much.

PART NUMBER SEARCH RESULTS WITH PRICES
Vehicle 1979 Mercedes Benz 300D
Part: Fuse
Note: 50 Amp.
for Pre-Glow Relay
Federal
Chassis: -164520
P2010-11768 Fuse Germany IN STOCK

No it is a piece of metal called a strip fuse. Fifty amps on the series glow plugs or 80 amps on the pencil type.

No it is a piece of metal called a strip fuse. Fifty amps on the series glow plugs or 80 amps on the pencil type. A screw on each end to terminate it.

Update -

I have figured out part of my problem. The wire that runs from the back GP to the box on the firewall has been altered and has had a 3/4 12-10 gauge eyehole put on the GP end. The old GP has a metal bushing at the beginning of the threads for the little nylon piece to push the eyehole against, creating contact with the GP. The new GP's don't have as as wide a bushing, so the eyehole slipped over it.

I put one of the old GP's in and the light came on once or twice then stopped. So am I right in thinking if I get a new GP with that wide faced bushing, it will work?

Or, simply, is there a correct wire with the correct ends floating around? LOL

I gotta see some pics of what you are dealing with.
check out this pictorial on GP upgrading. made a world of difference in starting my 79TD
http://www.dieselgiant.com/mercedesdieselloopglowplugrepair.htm

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Issue fixed!

What happened was that when PO put this new eyelet on the wire coming off of the firewall, he rigged it to work with an Autolite 1102 glow plug, which has a larger collar around the outer stud. My Beck-Arnley GP's had a small collar that the eyelet just slid over.

Found some AL 1102's at the O'Reilly's Distribution Center in Little Rock. Cha-Ching!

Unfortunately, since those AL plugs are crap, you will be changing them again in short order. So you will eventually need to get a correctly sized eyelet for the good glow plugs!!

__________________
1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150