'95 E300D...replaced fuel lines, now barely runs - PeachParts Mercedes-Benz Forum

NoSpark · #1 11-20-2006, 03:16 PM

I recently did all the fuel lines/o-rings/filter/copper washers on my brother's '95, and it barely starts, barely runs, even flooring it. It started and idled fine when I first finished the job, but would bog down and struggle to maintain 15mph. My brother thought he could figure it out, went in there and bled the "plungers" off the pump (technically I think those are the injectors, while the nozzles are atop the head??). Anyway, he forgot to tighten one of nuts atop the injector. I think he introduced a bunch of air into the system...although the new fuel lines sure look free of bubbles.

I've seen it posted before that the '95 and later models are supposed to bleed out air in the fuel automatically...but i have to ask, is there a manual IP bleeder valve like on the older diesels?

I've tried bleeding out air by cracking the nozzles one-by-one, and even the injectors off the pump. A friend of mine did this on his Cummings diesel 2 weekends ago and that fixed his ills. Does this mean the lift pump needs replacing? I did notice that the stop knob bolt atop the fuel filter seems to be leaking out of the knob part, not from between it and the housing (I replaced both o-rings). I tore the bolt off my '99, but it has a bigger internal diameter for greater fuel flow. That didn't solve anything. Argh!

Any advice is welcome. Thanks.

TMAllison · #2 11-20-2006, 04:12 PM

Just like our 99's, fix the air leaks first (ie: stop switch on top of filter).

It is self priming by use of the starter motor like our 99's too.

Is the MAF still connected up? EGR and resonance flaps? Each of those will bog you down.

longshore1 · #3 11-20-2006, 07:58 PM

I have the same car. I just replaced all my fuel lines with clear ones. I have a small air leak coming out of the prefilter. I need to get a new o ring for the prefilter. I used a 99 cent siphon pump to pump all the air out of the lines. runs good but still a small air leak that effects the start up if it sits over a few hours. make sure the lines are in the correct order. fill the fuel filter up to help get the air out.

NoSpark · #4 11-21-2006, 11:30 AM

Thanks guys, but I've replaced EVERYTHING that could cause a leak. All the fuel lines, o-rings, and copper washers. Everything is hooked up correctly yet it won't start or run unless I floor the throttle. And even then it only runs for a few seconds.

Isn't the first time I've done a job like this, I know about topping off the fuel filter and whatnot. And bleeding the injectors. It's just that nothing I do seems to make any headway. A manual bleeder on the fuel pump would sure come in handy, I feel like I'm abusing the starter.

scott19_68 · #5 11-21-2006, 11:50 AM

If you are absolutely positive that there are no air bubbles coming up from the lift pump to the spin on filter (the one on the far right when standing infront of the car and facing the engine) then it might be that one of the seals on the spin on filter is bad or you have not tightened it enough. Are you positive that the O-rings on the bolt that holds the spin-on filter to the housing have not been damaged?

TMAllison · #6 11-21-2006, 12:00 PM

Quote:

Originally Posted by NoSpark

I did notice that the stop knob bolt atop the fuel filter seems to be leaking out of the knob part, not from between it and the housing (I replaced both o-rings).

Has this leak been fixed yet? Its the manual kill switch, and its leaking....

NoSpark · #7 11-21-2006, 12:33 PM

Quote:

Originally Posted by TMAllison

Has this leak been fixed yet? Its the manual kill switch, and its leaking....

Well, I used the bolt off my '99. The inner diameter is bigger, but it'll seal off the leak for now.

scott19_68, I see no air bubbles and the fuel filter is on as tight as i dare. The original bolt holding it was wicking a small amount of fuel from above (not from between the bolt and fuel filter housing), I assume fuel is getting past the ballcheck valve inside it. I replaced it w/ the '99's bolt for the time being. This should seal off the system while I run down the problem.