Need opinions please - PeachParts Mercedes-Benz Forum

ColLonewolf · #1 08-18-2008, 01:55 PM

Have an 83 300SD that I purchased a month or so ago. Been driving it around for all this time with no real mechanical problems. Moved last week and when I drove the car to the new house it was losing power and I had to put the pedal to the floor just to make her move. Got it to the house and figured the fuel filters were bad so I ordered a new set and put them in. Took it for a test drive and all seemed well. This morning tried to drive her to work and all seemed well till the car got to operating temp or there abouts, then she started sputtering again and lost all power. This eventually ended with her dead on the side of the road. Restarted her and away she went for about 100’ then she died. Decided to try to head for the house so I restarted, turned around and took off for the house like a bat out of well you know. Had her up to 60mph then the same thing she just lost power and when I got to about 35 she died. After this she would turn over and start but as soon as you let go of the key she dies. So short story long is it the lift pump or the injection pump or am I on the wrong path? What should I look for to find out? What should this repair cost me? Seam s like she is out of fuel but I see it in the inline filter and the gage reads a quarter tank at its lowest indication (she will bounce back and forth off and on to a bit under half then back to a quarter). None of my gages work 100 percent but the oil pressure. I tried to prime the system with the pump and when I was done she still would only start till you let go of the key then she dies. Enough ranting and raving. Any assistance on this matter would be greatly appreciated. Thank you for your time and effort.

Wodnek · #2 08-18-2008, 02:10 PM

Sounds like the fuel tank screen.

ColLonewolf · #3 08-18-2008, 03:04 PM

How do you get to that? How would I test for it? The tank is behind the seat and in front of the trunk so how easy is access? Thanks once again.

bob_98sr5 · #4 08-18-2008, 03:10 PM

cal,

i replaced the fuel tank screen and all the fuel hoses. i'm also going to replace some o-rings as well. the fuel tank screen on a W124 takes a 46mm special tool, but i made mine out of shelving brackets, a piece of metal, and a 1/2 nut. welding is required but saved me some coins. i also replaced the fuel thermostat parts too. i had 3 lines that were weeping fuel big time too. not to mention, the return hoses were weeping too.

now my engine runs very smoothly, hardly any diesel fuel smell, etc. i have a post that address all of this.

bob

Bajaman · #5 08-18-2008, 04:10 PM

It's clear that your not getting sufficient fuel. Start with the tank screen and work your way forward checking all of the rubber/clamps. Also make sure there is enough fuel in the tank. Don't mess with the lift pump until this has been done.

kerry · #6 08-18-2008, 06:07 PM

Switching inlet and return lines will tell you if the tank screen is plugged on the inlet line. Running it on an alternative fuel supply under the hood (as if you were doing a diesel purge--see dieselgiant's website) would also confirm if the problem was in the tank.

Bens lover · #7 08-18-2008, 06:54 PM

Have you had a look at your primary fuel filter? (The one that is transparent)
I have seen this before that it clogs up so bad....

LUVMBDiesels · #8 08-18-2008, 09:19 PM

Open the fuel filler. Do you hear a whoosing sound of air rushing into the tank? The vent could be blocked. Do a search for fuel vent to see how to unblock it.

Diesel911 · #9 08-18-2008, 11:39 PM

If your Fuel Tank is contaminated it could be the Tank Screen as the others have said but it also could be that both filters did their job and are plugged again. I would change both filters again but save them incase they are Ok. I would get a separate container of clean diesel fuel and run a fuel hose into the separate container (5/16 of an inch works). this will completely bypass your fuel tank.
If your car runs normal like that you know that you have a tank problem.
Exchanging the Fuel Return Hose and the Fuel Inlet hose will also work (a good way to find it the Tank Screen is blocked) but if you have crap floating in the Fuel itself it might plug up your filter again.

JimmyL · #10 08-19-2008, 12:15 AM

Quote:

Originally Posted by ColLonewolf

Got it to the house and figured the fuel filters were bad so I ordered a new set and put them in.

Quote:

Originally Posted by Bens lover

Have you had a look at your primary fuel filter? (The one that is transparent)
I have seen this before that it clogs up so bad....

Diesel911 · #11 08-19-2008, 02:19 PM

Quote:

Originally Posted by JimmyL

I saw those statements but if your fuel is cruddy enough you might change a whole box full of filters and still have problems. The primary filter is an nominal 20 micron filter (the mesh looks bigger than that to me) so it is possible for the primary not to get plugged and the Secondary Filter to get plugged.
My thought was that for trouble shooting buy new filters again and eliminate them as a source of the problem while at the same time using a source of clean fuel that would not plug the filters again.

compress ignite · #12 08-19-2008, 08:55 PM

Take 8 Oz. bottle...Dump into Diesel Tank (Then top off tank with diesel)...
Drive it like you "Stole It" for 20 miles to mix the contents of the tank...
Within 3 days problem will have gone away.

ColLonewolf · #13 08-20-2008, 09:03 AM

Looks great if it works but I still have to get it to run before I will be able to run it at all. Thanks for the info and your time. How do I get to the pickup screen? The same way you get to the sending unit? Through the first aid kit storage? Thanks once again.

kerry · #14 08-20-2008, 09:06 AM

No. The screen is screwed into the tank at the bottom where the outlet hose is. The tank will need to be drained. I would not got to that effort before either switching inlet/return lines or running on an alternative fuel supply to confirm that the problem is with the tank screen.

Bens lover · #15 08-20-2008, 11:44 AM

Here is what I found at my local marine store...It works great and only needed two applications.