Finally got my "new" '84 running again. When I got it the fuel was gelled coal black. So I removed the tank, flushed it, replaced worn fuel lines including the three hard plastics around the fuel filter. Fuel tank strainer replaced and primer pump updated. Then everything was plugged back in. Changed out the main fuel filter and reinstalled the pre filter. During priming up the system the prefilter was colored pitch black from the residual gas flowin from the steel line. Then it all cleared up. After much bleeding I started her up expecting to restart/prime a few times. To my surprise it started up the first time within split seconds and never faltered - wow!

Now to my electrical problem I am going to have to revisit tonight. For some reason, when I turn on the head lights, without engine running, the fuel gauge and temp gauge spin up to max and the directional signals and high beam indicator light up solid solid I am hoping to cut down on a few hours/days of hunt and search with some friendly assistance here? Any suggestions?

I would start with a check of the main grounds, batt.-chassis and chassis to engine. On mine, a loose bracket on the engine, that the ground strap attached to, caused strange guage problems. Another suggested area is the terminal strip that the alternator and starter attached to, on the passenger fenderwell. Hope that helps and let us know what you find.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

After following SD Blues advice, if the problem is still there, pull the instrument cluster, it is not hard to get out, and wiggle, remove and clean all the various ground lines there. There is a big one with several brown lines all attached in one place to the steering column. That may be the problem, or the steering column may not be grounding.
Good luck, This could take a while to sort out.

Thanks for you feedback guys!

So here's the update from last night tinkering. I've rechecked the ground connections under hood and added another ground cable. Rechecked the fuses then tested for the problem by turning on the head lights, several times, without engine running. Same problem cropped up - directional signals lighted up solid and the fuel tank gauge swung to the other side of the scale to full. Then i started the engine and switched the lights on and off a few times. Bingo, the problem went away.

Thinking the problem was resolved I proceeded with other maintenance stuff. Poured some more diesel with Power service in the fuel tank. And a few ounces of Rislone into the crankcase. Tonight I will be replacing oil and filter then drop the wheels to inspect the brakes. I am expecting the car will need new rotors, pads and probably front bearings. Done with the night I proceeded to take the car back into the garage. Well what do you know the problem returned, directionals solid, fuel gauge needle against the right end, blue high beam indicator on. I stop the car then drop into reverse for a few inches and the problem goes away again Oh well at least with a few shakes, on and off this and that this problem is somewhat under control. I'll just have to go over the rest of the grounds, connections behind the dash cluster. And of course more research

Congrats on your new buggy. It sounds like your fuel system had a serious case of fungus. Add some Diesel biocide to your next tank of fuel to kill whatever is left so it doesn't grow back. Be prepared to change your fuel filters more frequently until this gets all cleaned up.

I agree with the other posts, you most likely have a bad ground connection. If all of these check out ok, you might need to check out the voltage regulator on the alternator.

TimK

__________________
85' MB 300D Turbo
85' GMC Suburban 6.5L Diesel Turbo
2000 VW Beetle 1.9L TDI Diesel Turbo
67' Land Rover 2.5L Diesel - No turbo

So what do you do when it's so cold out your fuel gels? Smear some on toast and have another cup of coffee until it warms up outside.

Look for ground wires that connect to engine/alternator and that might be a little "tight." Your experience of putting into reverse and the problem clearing is significant.

Engaging reverse will torque the engine a bit, moving it the "other" direction.

Sounds like a connection that is pulled loose and allowed to reconnect.

Good luck and good hunting!

Best Regards,
Jim

So far the "fix" seems to be holding up. Ever since I added an additional ground cable between battery and front fender things settled down

This might be a little out there, but check for voltage on your cluster ground wires. I had a 98 CLK that gave me fits with it lighting up all the cluster indicators dimly at random. Found voltage on the ground wires behind the cluster and smoked rock-hard wiring.

__________________


1980 500SE/AMG Euro
1981 500SEL Euro
1982 380SEL
1983 300TD
1983 500SEC/AMG Euro
1984 500SEC
1984 300TD Euro
1986 190E 2.3-16
1986 190E 2.3
1987 300D
1997 C36 AMG
2003 C320T 4matic

past: 1969 280SE 4.5 | 1978 240D | 1978 300D | 1981 300SD | 1981 300SD | 1982 300CD | 1983 300CD | 1983 300SD | 1983 380SEC | 1984 300D | 1984 300D | 1984 300TD | 1984 500SEL | 1984 300SD | 1985 300D | 1986 300E | 1986 560SEL | 1986 560SEL/Carat | 1987 560SEC | 1991 300D 2.5 | 2006 R350

you likely have a ground cable thats broken or corroded internally...your "fix" tends to point at this. It may be time for a new one and a new ground strap from chassis to motor too.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

Johnhef & Boneheaddoctor

All very good points. I will have to get behind the cluster sometimes soon to fix the clock. So that will be a great time to poke around for bad & brittle cluster grounds.

Yes the ground cables from chassis to engine were already replaced with heavy duty welding cables. So that bad "internal" ground seems to be the most likely suspect.

Best Regards,
Peter