Injection pump needed?? - PeachParts Mercedes-Benz Forum

ImBroke · #1 06-23-2004, 04:17 PM

In my continuing quest to both get this car running, and to learn more about diesels, I have a question. My injector pump will only squirt fuel out of #4 hole. I tried moving the big nut thing, spring, etc.. to another spot, and only #4 works still. With all of the assemblies removed, I can push the priming pump and get fuel out of all 5 holes. (I know, real technical jargon going on here).
I think I need an injector pump that will actually pump on all 5, but that is just MO.
I have replaced the priming pump, and bled the lines countless times. I'm getting pretty fed up with the whole ordeal.

whunter · #2 06-23-2004, 05:12 PM

Your description leaves a lot to be desired.
I had to check your profile to find that you own a 1977 300D.
Could you post digital pictures?
It is possible that you do need an injection pump, but; nobody here can answer your question from your description.
More data needed also:
#1. Total miles?
#2. Any vehicle history?

Cute name "I AM BROKE". LOL

P.E.Haiges · #3 06-23-2004, 07:44 PM

I'm,

Before you screw up the IP by taking it apart, take it to a Diesel injection shop and have it tested. That's the only way you will know if it is OK or needs to be repaired.

P E H

ImBroke · #4 06-23-2004, 07:57 PM

Quote:

Originally posted by whunter
Your description leaves a lot to be desired. Could you post digital pictures?
It is possible that you do need an injection pump, but; nobody here can answer your question from your description.
More data needed also:
#1. Total miles?
#2. Any vehicle history?

Ok, sorry for being vague,, this was a continuation post after doing more troubleshooting.
You want details, I hardly have any..
You are correct, it's a 77 300D.
Total miles?? 257k.
Vehicle history? Donated to charity, I bought it at an auction for $150, to play around with and learn about diesel engines.
My age, 39. Current vehicles owned,, 04 F150, 02 Mustang GT Convert, 95 Honda Del Sol, 88 IROC, and the Benz. Gas experience, over 20 years,, diesel experience,,less than 20 hours.

What have I done so far? Replaced priming pump. Cracked the lines and bled them going from the big nut on top of the filter, to both banjo bolts on the injector pump, no air bubbles.
Removed the hard lines going from the injector pump to the injectors, and I can hand pump and get fuel out of all of them. However, when cranking the engine over,,, only #4 shoots fuel out. The others do nothing.
I have a question though.. when I hand pump it, the clear primary filter empties,, after I stop, it fills up again,, is that normal?

What digital pics do you need, I'll get them up.

P.E.Haiges · #5 06-23-2004, 08:08 PM

I'm,

The fuel strainer in the fuel tank may be plugged causing the fuel filter to fill slowly.

P E H

ImBroke · #6 06-23-2004, 11:34 PM

PEH,, I was looking at another post by Odie, and I think we're in the same situation. My car appears to have been sitting for a while, due to the 3 wasp nests I've found. One regular and 2 mud daubers. I put fuel in, but was only able to get in 2 gallons, so I think it could have been sitting for a while with almost a full tank (gauge reads full). His post mentions Diesel purge, and trying to get it to start that way,,, sounds like a plan to try. With a full tank, I'm reluctant to get the bath changing tank filters,, but I may have to suffer..

whunter · #7 06-24-2004, 03:13 AM

Wow, back to basic diagnosis.
#1. Forget the fuel tank for now.
#2. Try to follow my crude graphic.

You have two fuel lines to the engine, input and output.
disconnect them and use rubber hose to feed from a fuel can.
Doing it this way totally eliminates the fuel tank questions.
running out of time, will answer questions tomorrow.

dabenz · #8 06-24-2004, 07:53 AM

If it was me, knowing that small critters had gotten to the car, I'd start at the beginning. Get some fuel jugs and siphon as much fuel out of the tank as you can. Pull the tank bottom plug and get the gunk out. Pull the tank strainer and get the gunk out. Find the tank vent (if there is one - may be vented through the cap) and get the gunk out. All need to be done to a high mileage car that you don't really know the history of. Then take the injector pump to an injector shop you can trust, meaning make them show you their books for YOUR pump. And remember to put new gaskets in the tank plug and strainer.

whunter · #9 06-24-2004, 08:40 AM

A can of Diesel Purge may be substituted for the fuel can.
You only need to get it diagnosed and/or started.

P.E.Haiges · #10 06-24-2004, 09:05 AM

I'm,

You can drain the fuel from the tank by removing the fuel line from the tank where it is connected to the steel fuel line. Drain it into buckets. If your tank is full, you will need 6-5 gallon buckets.

I just thought, if your strainer is badly plugged, the fuel may take a long time to drain out. Anyway, if the fuel doesn't run out very fast, you know the strainer is plugged. This is usually caused by algae in the fuel. You should treat tank with an algeacide.

The fuel can be used , just strain it thru a cloth and treat with algaecide. NO sense throwing almost $50 of fuel away.

P E H

ImBroke · #11 06-24-2004, 11:19 AM

Guys,, I have been paying attention to Odies posts as well, and if his car can run, so can mine. It did sputter a little earlier, but never fully caught on. To me, it was acting like it was catching on a cylinder or two, but not all of them. I went for the pump because when I primed it (earlier), I got fuel out of the tops of the injectors, and when I cranked it, I got hardly any. I'll put it back together and try doing the fresh fuel sucking tonight.

Would it hurt to pump by hand while cranking?? Just a thought, maybe it would help get fuel up there??

I'm going to keep trying this thing,, maybe keep a stopwatch with me so I know how long I've been cranking.

I don't know what an injector pump is supposed to look like when it's working, hopefully it looks like mine.

george d · #12 06-24-2004, 12:58 PM

ImBroke,

I am a newbie to this diesel forum as well, but I had to change my fuel filters after about the first week. The mechanics at the dealer (where I bought the filters, because it stopped running on the street near my driveway, and I had to get it off the street ASAP) told me to fill the big filter with ATF fluid or diesel, and have a friend crank the engine while I was pumping the primer pump, until it would run. That is what I did, and it started up shortly, but I had to pump for a while.

George

WANT '71 280SEL · #13 06-24-2004, 11:18 PM

I thought that if the primer pump is loosened then it will be pulling in air. So if your pumping while someone's cranking, it is just pulling in air isn't it? I'll be followinng this thread as I find it to be very interesting.
Thanks
David

kmaysob · #14 06-25-2004, 12:01 AM

Quote:

Originally posted by WANT '71 280SEL
I thought that if the primer pump is loosened then it will be pulling in air. So if your pumping while someone's cranking, it is just pulling in air isn't it? I'll be followinng this thread as I find it to be very interesting.
Thanks
David

i think that would only be true with the old style primer pump.

dabenz · #15 06-25-2004, 08:24 AM

That hand pump is there to save your battery (or a pull start). If the engine is spinning then the fuel pump is too.