300TD...no fuel - PeachParts Mercedes-Benz Forum

Mismost · #1 11-20-2007, 08:13 PM

Yesterday I put 20 bucks worth of fuel in the wagon, then washed it, and then it died!

I assumed it was the small fuel filter and changed it out...the old one seemed clean and it was easy to blow through. Well, after much cranking and priming with the hand pump, there is still no fuel showing in the new filter.

Is there a "pick up pump" on these wagons that pushes fuel to the injector pump? If so, where is that puppy?

kerry · #2 11-20-2007, 08:17 PM

Gravity fed. The TD tanks is lower than the sedan so has less of a gravity pull on the fuel but I think you should get some flow if you remove the line fromthe primary filter and hold it downwards below the tank level. If you get no flow, there's a problem upstream somewhere, possibly a plugged tank strainer.

toomany MBZ · #3 11-20-2007, 10:15 PM

Quote:

Originally Posted by Mismost

Yesterday I put 20 bucks worth of fuel in the wagon, then washed it, and then it died!

I assumed it was the small fuel filter and changed it out...the old one seemed clean and it was easy to blow through. Well, after much cranking and priming with the hand pump, there is still no fuel showing in the new filter.

Is there a "pick up pump" on these wagons that pushes fuel to the injector pump? If so, where is that puppy?

When primping, did you open a vent for the air to escape to?

Mismost · #4 11-21-2007, 01:53 AM

Ok, I'll try the gravity deal in the morning.

Where is the "lift pump" on these wagons.

Where is the vent that needs to be open when priming?

pawoSD · #5 11-21-2007, 03:43 AM

Open your cap to the tank too....make sure there's no vacuum in the fuel tank. If the vent line is plugged it can easily happen....

toomany MBZ · #6 11-21-2007, 04:35 AM

Quote:

Originally Posted by Mismost

Ok, I'll try the gravity deal in the morning.

Where is the "lift pump" on these wagons.

Where is the vent that needs to be open when priming?

The primer pump is located on the driver side of the engine. Follow the fuel lines from the firewall, you'll find it. The old style pump has a white round handle, unscrew, and pump, when done push all the way down, and screw clockwise to lock. The new style is black, and needs only pumping, as it has a spring.
You have two filters, a clear one in-line, and a spin on one that looks like an oil filter, again follow the lines. It is located just behind the power steering pump. Forgive me if you already know this.
Anyway, loosen the small banjo bolt on top of the housing, the one with three lines, when priming. If replacing that one also, fill up with fuel before installing.

240Demon · #7 11-21-2007, 04:35 AM

Your lift pump is located on the injection pump...where the primer is and the little filter...

I would agree with the tank strainer idea...as I have seen them get plugged with algae and the like. It isn't hard to clean...you just have to drain the tank and then use some ginormous socket (can't remember what size off the top of my head) to get the strainer out.

peterhardie · #8 11-21-2007, 08:26 AM

Will cause no-start. It lets air into the system, starving the IP. That might explain why the car died all of a sudden (happened to me) and why you are not getting any fuel pumping.

Dee8go · #9 11-21-2007, 09:55 AM

I guess the fuel system works on the hydraulic principle? If you get air in the fuel line, it ceases to draw from the tank? Is this only true of diesels, or do gassers work the same way?

winmutt · #10 11-21-2007, 10:03 AM

Swap the tank lines and it will blow out the tank screen. Be prepared to have plenty of prefilters on hand.

LUVMBDiesels · #11 11-21-2007, 10:20 AM

Quote:

Originally Posted by winmutt

Swap the tank lines and it will blow out the tank screen. Be prepared to have plenty of prefilters on hand.

Last time I did a diesel purge I connected my air compressor to the fuel line and blew about 20psi down it. (tank was less than 1/2 full) I opened the fuel cap too. That blew away any gunk that had collected on the strainer and the amount of fuel getting into the primary filter has increased. That was six months ago and the strainer has not clogged up yet.

BIGRED · #12 11-21-2007, 10:40 AM

Not sure if it helps or not...I know it can't hurt...when changing fuel filters as part of maintinance...

Quote:

Originally Posted by LUVMBDiesels

...air compressor to the fuel line and blew about 20psi down it. (tank was less than 1/2 full) I opened the fuel cap too. That blew away any gunk that had collected on the strainer and the amount of fuel getting into the primary filter has increased.

along with a shot of some type of gunk killer.

Don

Mismost · #13 11-21-2007, 11:03 AM

while cruising the site last night I also came across this bit of info....

reverse the feed / return fuel lines

I think that just might tell me if it is a bad lift pump or just a bad prime problem or a sucking air situation.

Have already blown the fuel line with compressed air back into the tank...it made bubble noises!

Mismost · #14 11-21-2007, 12:04 PM

while cruising the site last night I also came across this bit of info....

reverse the feed / return fuel lines

I think that just might tell me if it is a bad lift pump or just a bad prime problem or a sucking air situation.

Have already blown the fuel line with compressed air back into the tank...it made bubble noises!