fuel system check
 

Hi,
My mercedes 300 D turbo is have a problem where after 5 seconds or so the engine dies, i am able to rev it up as much as i want, and even if im holding it at 5krmp it will still cut. Iv checked almost everything it seems. Iv replaced the fuel filter,prefilter and checked the screen in the fuel tank. Iv bled the system numorous times, changed the fuel, replaced some of the fuel lines. and tried to check for any leakage.
I emailed the guys at diesel giant and asked them, they said it sounds like air is leaking into the system. Makes sense. seems like that would be the last option.
Is there any way to check if air is leaking in? how do you find where its happening, is there any common place this happens? is that my last hope, before i spend a lot of friggen money getting this baby towed , which i dont really have at the moment.
thanks for any help

dan

RE: fuel system check
 

I checked the vacuum hoses, and found the several were disconnected, reconnected them, no change. then disconnected the hose from the injection pump, no change.
I looked at the prefilter and didnt notice any bubbles passing through, though there is a big one there. Would there be a stream of bubbles if the car is only running for a 5 seconds or so? also, the engine seems ot run a little bit longer when the engine has warmed up. perhaps b/c its more fuel effiecient when its warm.
anyways. if the bubble arent streaming through, then is there a possible leak after the prefilter? is the a possible clog anywhere? is it a mechanical piece that has gone bad, like the injection pump or something? im pretty lost at this point.

thanks

dan

RE: fuel system check
 

hey,

I was talking to my boss today about the symptoms of my mercedes. He doesnt know a ton about diesels, but he did say that (at least for his cummings) there is a secondary pump that pumps in some fuel during the preglow and/or choking. He said that maybe the reason it dies every time after about 5-6 seconds is because the main pump is bad, and the initial 5-6 seconds of running time is just the fuel that the secondary pump pushed in. and that the injection pump is bad.
Is this a possibility? not sure, but i havent heard anything about a secondary pump. Makes sense i suppose, seeing has nothing else is making any difference in the performance.
Could someone advise me on this please?
thanks

dan
(1983 mercedes 300 d turbo)

RE: fuel system check
 

any suggestions?

RE: fuel system check
 

Sounds like the rack stop is too tight. On the back of the injection pump there is a spring loaded device that keeps the injection rack from shaking, loosen the lock nut and turn it out 1/4 turn and tighten it back down. If you go too far the motor will shake at idleafter warming it up or after driving it on the highway for a while. I would clean it off real good and paint mark it before adusting it.

RE: fuel system check
 

Before you do that, how long has it been since the valves were adjusted?