83 300D: Intermitent glowplug light, full time no start

[car54]

I'm sure I could answer my question if I kept searching, but I didnt see anything relevent in my search so I thought id post.

today, the coldest day of the year so far, my 83 300D wont start. In the past, the glowplug light doesnt come on every time you turn the key, but they were always working because it always started, even if the light didnt come on.

This morning the glowplug light wouldnt come on, and the car wouldnt start. I checked the fuel filter and the fuel wasnt gelled up. It wouldnt make sense for the fuel to be gelled because my other diesels arent gelled.

I think the glowplugs finally quit firing. Obviously I need to get this fixed and because I dont have a book on the car or any knowledge of the electrical system on the car, I think I'll take it somewhere. Of course if you think its an easy fix I'd love to try it.

so.. anybody have this problem, know a fix, or do you know of a good independent w123 expert in the DC area? I have the list from my previous post on a 92 300D 2.5T timing chain job and will try them.

Thanks for your help.

[mechmagcn]

First check the fuse link at the glow plug relay, then unplug harness and check individual plugs from there. Fuse sometimes looks good but doesn't make connection, so check with test light or volt meter.
Jeff

i agree w/ mechmagcn. very easy to remove the fuze from the glowplug relay (2 screws)...run it betwixt your fingers to "clean" the contacts etc.....how cold in Va.?>anyway, possibly AIR leaking into fuel lines.........you do NEED high compression:valves PROPERLY adjusted....clean fuel filters and tank screen. Also, clean grounds and hot leads to alternator, starter, battery, etc.: clean air filter. FRESH diesel fuel. a GOOD (ie;fast spinning starter)................if all goes well:compression=FIRE!............less than this can be HELPED w/ KEROSENE and or an additive for the fuel (power service white bottle helps w/ gelling and cetane boost!).............if STILL no luck (do you know the line about no luck at all?).....plug that B***H in w/ the block heater!> if you ain't got one "o"them, see other previous posts concerning alternate methods of block heating. including the old FIRE method! good luck and best wishes always...spo P.S.; haven't seen your posts for a while. hope all is well.

[car54]

as a Volkswagen TDI mechanic by day. I sort of know thesse cars, but I dont know the exact electrical systems. I checked the glowplugs, and even though the light isnt coming on, they ARE getting power and heating up. They have different resistance readings all over the place (1,3,5 are pretty low resistance, 2,4 are much higher) I checked the relay and it is operational even though the light doesnt come on. I loostened an injector line and there is no fuel spraying out as I crank the engine over.

I checked the stop lever and it is in the normal operating position.

I checked the fuel filter and it isnt gelled. I even put a heat gun on the injection pump for half an hour and got it warm to the touch, nothing.

One side note.. this car is equipped with the factory theft prevention shutoff switch that shuts the motor down after 60 seconds if you dont trip the switch hidden under the dash. I'm not sure how this is wired, does it just cut the fuel pump off the same way the ignition switch does? Is it wired to another seperate electrical system shutoff or somthing? The hand primer pump will dump boatloads of fresh ungelled and clear (not clouded) diesel fuel all over the place if you remove the return to tank line. Gelling is definently not a problem. I believe somthing is wrong either internal to the fuel pump, or there is a trick to the shutoff circuit I have not found, or the electrical shutoff switch has somehow tripped and refuses to reset and allow the engine to start (whern cranking over, it does sputter a little bit sometimes, but it doesnt produce any smoke)

I somehow have a fuel pump problem. It ran fine the night prior to this happening. In fact, this is the first problem ive had with it starting. Everything mentioned above is in good condition (battery, starter, alternator all less than 2 yrs old) air filter less than 10,000 miles, fuel filter less than 10,000, good valve adjustment)

any ideas now? I really wanna see it run! I miss my 300D!

[240 Ed]

FWIW dept...

I replaced the glow plugs on a Yanmar diesel engine and now the thing starts. It doesn't jump to life like it used to when the engine was fresh, but it does start.

I would suspect that if you are getting various readings on your plugs, then you could try replacing them. If your plugs are getting juice (and are good), then the engine would start IF it had fuel and air.

Does the hidden switch prevent the fuel delivery switch from working, thus no fuel?

[Rick Miley]

car54, I think you need to repost your question with a different header. It looks like everyone is getting hung up on the glow plugs, and missing the part where you said no fuel is coming out of the injector line. I bet LarryBible or engatwork could help you, but you need to get their attention with the proper heading.

Wish I could help, but I've never owned a W123.

[Rick Miley]

I just happened to be browsing the Tech Help forum and found this currently active thread about the same problem:

no fuel in injection lines


In particular, look at the post by mercedesmatt about vacuum. That sounds like the problem in your case.