Hot wire glow plugs for 240D? - PeachParts Mercedes-Benz Forum

jcwells · #1 11-08-2003, 02:18 AM

Hello All:

I just purchased a 1983 240Dparts car for its 4 speed transmission, and I am planning on converting my auto 240 into a stick this month. I would also like to checkout the engine before everything is removed. Some of the components such as the lights, stereo etc. have been removed, and there is the odd dangling wire from these quick removals prior to my purchase. It does turn over fine by the key but there is no dash glow light and no voltage to the glow plugs in the on position. The plugs test fine and the plug relay/timer is still there, (and there is fuel) but I don’t really want to spend the time tracing down the wiring fault. The car is scrap after I’m done so can I just cut the leads to the plugs away from their connector, and apply 12 volts for 15 seconds or so and start the engine, or are the plugs not designed to see a full 12 volts.?

Thanks,

John

P.E.Haiges · #2 11-08-2003, 03:01 AM

jcwells,

If they are the parallel type GP (separate wire gpoing to each plug) they are 12 volt GP and connecting them directly to the battery will not hurt them.

P E H

Ken300D · #3 11-08-2003, 10:14 AM

Yes, you can put 12V directly on the glow plugs.

It may be simpler for you to find just the one lead that throws the glow plug relay and hot wire THAT to the battery. We can probably look up the wire number for you. This assumes you are seeing 12-V on the big supply wire into the relay and the strip fuse is still good.

Doing a hot wire this way involves a lot less "jumper" current. Normally each glow plug is going to start off at 20-amps plus and drop down to 12-amps or so when it gets hot. So you would be looking at trying to jumper 80-amps to start the glow plugs.

Some of the early Yanmar diesel tractors from Japan did not have glow plugs at all to start them in cold weather. As an option, you could get a thermostart system. You had this little half-pint bottle you filled with diesel, and you threw a certain switch (position of the key I think) on the dash. This heated up something like a cigarette lighter element in the intake throat - and a line coming down from that little bottle dripped slowly on the red hot element. So essentially you had a little fire going in the intake.

Ken300D

jcwells · #4 11-08-2003, 12:39 PM

Thanks for the tip.

Pulled out the wiring diagram and jumped the brown to ground (forgot the number) and put power to pin 15, the relay clicked on, 30 seconds or so and it clicks off, jump in the car and instant start.
Full oil preasure at idle, no visible smoke and a great idle. Drove it around a bit and it sure is snappier to drive than the auto. I must say though that the shifter is a little sloppier than my Datsun, I assume that is typical.

As for what needs to be done to the tranny before the transplant, I read front and rear input and output bearings and seals. Is this straight forward? Anything else?

Thanks again. I will try and post some pictures as the project progresses.

John