PeachParts Mercedes-Benz Forum - View Single Post - 83 300D: Intermitent glowplug light, full time no start

car54 · #4 01-24-2003, 01:43 AM

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!