Hi All,

Some brief history: I only drive my 300D turbo in the summer, which is about May through October here. Parked it for last winter with a full tank, once in a while I'd start it up and let it idle for 10 minutes or so on a warm day. Spring rolled around and I got hot to try some minor repairs on it. I removed and cleaned the valve cover with the intention of putting on a new gasket so it wouldn't drip oil all over the engine, and discovered hairline cracks around where the hose goes out to the air filter (which has some oil in it). Being in there also was enough to aggrevate the old hoses that go from injector to injector into cracking at the ends and leaking fuel. So, I got some new hose and replaced those. I cleaned the valve cover and put it back on (old gasket for now until I get a new valve cover), reassembled the throttle assembly. (Over)Charged the battery, stuck it in, and got only weak crankage.

I was getting busy and so it went to the local shop. It now has a new starter and a new battery and turns over fine but will not stay running (mechanic's words). After dropping nearly $500 I wanted to get some more opinions before proceeding with any more work.

So: my first thought is that I failed to completely bleed the fuel lines of air. Is there any special procedure required to ensure they only contain fuel?

Then, what other possibilities are there? The mechanic said some of the vacuum hoses were looking brittle/showing some cracks, and the vacuum lock system for the doors is very slow and sometimes not functional so I know it's not holding a vacuum very well.

Sorry to be so long winded. Just trying to put all the relevant info out there. Any suggestions for simple tests I can perform, etc would be most valued.

Bill

There are more than a few things that will cause your diesel to run and then shut down as described. Vacuum is not one of them. The MB diesels run vacuum from a pump and not from the intake manifold.
First suspect would be the fuel. After sitting it may have fungi growing in it and that will plug up the supply. Usually can be seen in the clear prefilter, looks like black crap in there.
Next could be fuel lines, specifically the cigar hose. It runs from the steel fuel line near the engine cowl, about a foot long. You mentioned rotted lines and that one can get open sores and will suck air in, which will either cause the car to die after a bit, or will keep running with no power.
Be sure to check to see if fuel runs out the steel line with the cigar hose removed. If not fuel weeps out, you may have a problem in the tank with the strainer. Located at the bottom of the fuel ta\nk, it will get plugged if there is fungi in there.
There are other problems that will cause what you are telling, but check the fresh fuel supply first off. Most common, and cheape$t to fix.

Bill,

It sounds like a fuel problem. Check the fuel flow out of the fuel tank by removing the rubber fuel line where it connects to the steel line. If fuel barely trickles out, the tank strainer is plugged, probably from Fungus. If fuel runs out rapidly, strainer is OK.

It could also be plugged filters. Try blowing thru the inline filter. If fuel doesn't squirt out, its plugged. Only way to test secondary fuel filter is to replace and notice any difference.

Cigar hose has NO effect on running of engine. It is a return fuel line. Engine would run the same if U took it off except fuel would run out. Same with the injector return lines.

P E H

if any indication of fungi in fuel (black dots in prefilter) get some fungicide from your local truck tractor of marine supplier and kill it in the tank. usually this will also break it up so it can flow out thru the filter. then do it twice more to be sure you got it all.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Tom,

The fungus I had didn't break up by using Biobor fungicide. It was a brown, silicon rubber type substance that blocked the tank strainer. I couldn't find anything that would dissolve the fungus so I had to mechanically clean the strainer with an air gun.

If the fungus plugs up the primary or secondary filters, they will have to be replaced. This frequently happens after using the fungacide so carry spare filters.

P E H