Please Help - PeachParts Mercedes-Benz Forum

bajaranger88 · #1 05-03-2006, 05:20 PM

I have tried searching, but have not had much luck. My g/f's mom has an '87 TDT w/ the 6cyl. She was driving and it lost a lot of power so she pulled over where it finally died. she could start it up but then it would die again. I figure she ran it out of fuel, so i put 1g of fuel in but still nothing. I replaced both fuel filters as she usually runs biodiesel and they needed it. I can now get it to stay running sometimes w/ my foot on the floor, but its at about 1000 rpms. it acts like it really wants to fire and run but cant. The secondary fuel filter is full but the primary is not(has some fuel). I assume its because the system neds to be primed to re pressurize the system, but can not find the priming pump. Am I on the right track, Doesit have a priming pump, where is it, anyhelp would be appreciated, oh and its in the 70-80's here, so I'm pretty sure its not the g/p's, thanx.

mj_sid · #2 05-03-2006, 05:39 PM

If I remember right that should be a 603 engine. If its any thing like the 603 in my 300SDL there is no primer pump. It took forever for me to get fuel into the engine when I changed the fuel filters. I always get confused when it comes to the naming of the fuel filters. When I replaced my filters I added fuel to the big filter (I think it is properly called the secondary but???) by taking the bolt off the top and put a funnel in the hole. Then I added some diesel fuel; it made it much easier to start.

Are you sure that it is running diesel??? For some reason my gut is saying that it should start easier; I would double check that gas didnt accidently get put into it.

Good Luck,
Matt

pawoSD · #3 05-03-2006, 05:45 PM

If it ran out of fuel you need to put more than a gallon in the tank, thats nothing. Put about 4-5 in there and then try cranking it. If the filters are new/clean then the only thing I can think of that'd restrict starting is a clogged tank strainer, but it seems to sudden of a problem to point to that. Put in more fuel and try to crank it for a bit. If the primary filter is not full of fuel then there's a fuel shortage problem.

Also check the fuel lines for any place they could be leaking or letting air into the system.

Ken300D · #4 05-03-2006, 05:54 PM

To expand on the above comments, the reason one gallon of fuel is not enough to get the car restarted is because you are now sitting still. While the car was running the movement was able to slosh fuel around so it could be pulled into the fuel system intermittantly. Sure, there would be periods of time when only air could be pulled, but for some period of time you'd get enough fuel to run the car.

Now that you are sitting still there is no sloshing action, and without that sloshing the fuel can't reach the tank strainer. You have to overcome that with several gallons of fuel, not just one gallon.

Does the fuel level gauge show up down at the "R" or lower? I learned the hard way not to put too much trust in the "low fuel" light coming on. One time it didn't.

Ken300D

t walgamuth · #5 05-03-2006, 07:13 PM

it also could be fungus.

if more fuel doesnt do it you might want to get some fungicide and treat the fuel.

available at truck tractor and marine suppliers.

tom w

stcbenz83 · #6 05-04-2006, 12:57 AM

when i changed my filters this happened to me, i was to lazy to prime, so i started it, and kept the peddle on the floor for about 2 mins until the secondary filled up, it was running rough and would die if i let off the peddle, after about 2 or 3 mins, the engine started to rev up, i continued to let it rev just to make sure it was fll, ever since then, it has been ok

t walgamuth · #7 05-04-2006, 05:39 AM

you can also use wd40 or similar to prime it. take off the air cleaner and spray directly into the intake opening while someone else cranks. if everything is ok except lost prime it will start and run on the wd til you stop spraying, which you can do as soon as you see it is running on its own fuel supply.

good luck

tom w

bajaranger88 · #8 05-04-2006, 08:21 PM

I appreciate all the input. I will put more fuel ion to be sure but I don't think thats the problem, Every other vehicle i've ever worked on would start and run with a gal of fuel, after running out, the "sloshing" effect doesnt make that much difference. and it is getting fuel the secondary(large filter) has fuel but the primary(little one before the secondary) got almost full once but generally stays mostly empty, the fuingus on the tank strainer is a definate possibility, will add some fungucide with some more fuel. As for the wd40 trick, ive done that with gas engines(like starting fluid). however I wouldnt think that that would work with a diesel(due to the obvious differences between the 2). Still looking for moree help, THankx.

bajaranger88 · #9 05-04-2006, 11:05 PM

ttt

t walgamuth · #10 05-04-2006, 11:07 PM

wd40 will work in a diesel i have done it many times.

i bet you used ether in the gassers.

dont use ether in a diesel though...it will blow the head gasket and maybe worse!

tom w

Hatterasguy · #11 05-04-2006, 11:12 PM

Forget about the WD40.

Ok let me make sure I read correctly:
The car was running fine, lost power and died. I am assuming the fuel guage was probably on E so one would assume its out of fuel.

Clogged fuel filters is likely since all the crap gets sucked through them when you run the tank dry.

How much fuel have you added? If only 1 gallon add more! Like 5, then crank with your foot down and she will bleed off the air and start.

Also try this, disconect the fuel line before it goes into the hard lines that lead under the car. Stick that line into a can full of clean fuel and see if she will start.

Rick Miley · #12 05-05-2006, 10:37 AM

Quote:

Originally Posted by bajaranger88

the secondary(large filter) has fuel but the primary(little one before the secondary) got almost full once but generally stays mostly empty

That little filter can have a small bubble air in it, but no more. If there is a significant amout of air, then the pump is sucking in air instead of fuel.

P.E.Haiges · #13 05-05-2006, 10:52 AM

Baja,

Just because other cars will start on a gallon of fuel in an empty tank, doesn't mean the MB will. I had to add 2 gallons to my 300SDL with the 603 engine before it would start after running it out of fuel. There is no oprimer pump an a 603 engine.

Take the rubber fuel line (below the fuel tank) off where it connects to the steel fuel line. Notice how much fuel runs out. If it just dribbles the tank strainer is plugged. If a stream comes out, the strainer is OK.

Don't pay much attention to a lot of dirt getting sucked into the filters when running out of fuel. Just as much dirt will come out when running near empty and that doesn't clog any filters. The fuel and any dirt are a homogenius mixture from the fuel splashing around in the tank.

Here's another easy test: Take off the primary filter and blow thru it. If its easy to blow air thru it, the filter is not plugged.

P E H