Hi again, it's been a while.

I have the opportunity to look at a 300 td wagon tomorrow morning. Been searching for one all summer. It sounds like it's been a test vehicle for a local biodiesel producer here in Austin. The seller says that it's been with him for a number of years, and hasn't run it much lately, but that it had all manner of brews running through it in its early years with him. Now it won't start without help (he uses a rag over intake, if that makes any sense). He thinks the injection pump has gone bad. He says he checked out the injectors. I believe that it has been sitting for a while, and now won't start, and he doesn't want to get involved with it. Let's assume it's not the glow plugs, although he didn't say anything about checking them.

The price is under 1000, so I'm actually not all that worried even about a compression test, as long as the power feels pretty good. What I'm worried about is what can result from bad biodiesel. It probably has had all manner of mixes of diesel, glycerine, water and hydrocarbon running through it. Maybe adequately filtered, maybe not.

Thanks for any help.

Matt

assume that it is anything complicated to start with. i would start by draining the tank and putting fresh fuel in. then fresh fuel filters, air filter and oil change. then if it doesnt start i would check the glow plugs.

non experienced people always seem to want to blame the injection pump. but on a benz that is one of the least likely to fail.

that said the pump derives lubrication from the fuel so on some fuels it could sustain damage.

but i would start with the simple things first. always.

tom w

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[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.

Have a friend with a large car tow the MB for you. While being towed, turn ignition on and when the GP light goes off, slip it into S, the engine should start easily if the IP and fuel are fine.

NB, MB is one of a few manufacturers who provide this feature on their Auto transmissions.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

Have a friend with a large car tow the MB for you. While being towed, turn ignition on and when the GP light goes off, slip it into S, the engine should start easily if the compression, timing, IP and fuel are fine. Any one of these "out of spec" can prevent operation

NB, MB is one of a few manufacturers who provide this feature on their Auto transmissions.

__________________
Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

Keep rags away from the intake.. what a chance for a messy accident...

If it will run after one of these ' extra ' measures.. I don't think it is an IP problem... it is a starting problem... which is either temperature of the block or compression... which could also be valve settings or glow plugs...or battery/cables/starter speed....(the latter relate to the Speed of Compression... which relates to the temperature of the air at the point when the fuel is injected ). It could be an IP timing issue also... but generally the use of alternative fuels provides more lubrication to the IP as compared to less....
Bottom line... if it runs powerfully after started you will probably have only small things to fix to get it back to normal... follow Tom W's suggestions....
The symptoms described DO NOT call for towing the car to start it.