79 300SD, air in fuel lines. . . - PeachParts Mercedes-Benz Forum

imagesinthewind · #1 05-27-2006, 05:11 PM

I searched and didn't find what I needed.

So, I've been running a blend of bio, diesel and WVO and the car seemed to love it. More power (didn't even need to downshift on some hills that we normally have to) and the milage stayed the same, no loss of MPG.
Tom decided to not stop and get more fuel when the tank read R and the car
experienced a loss of power twice. Both times the car came right back.
I figured that since he let the tank get so low and we are using cleaner fuel that the fuel filter was clogged.
So, I took it out and took a look and it seems to be fine, not clogged, not black. I put some diesel through it, shook it up a couple times and emptied out the fuel and reinstalled the original filter. I did have a new one, but it wasn't a good one, opaque, couldn't see what is in it, so I put the other one back on.
Now she doesnt' start. She tries and tries. Ive tried 5-6 times for 20-30 seconds each time and it sounds like she wants to start but just never really catches on. I'm trying not to discharge the battery.
Anyone have any ideas to share?
Thanks so much!

(and no, it's not coked injectors, this is the first tank of blend we've done)

diametricalbenz · #2 05-27-2006, 05:14 PM

Did you bleed the air from the top of the spin on filter? If you didn't you'll crank your battery dead. To assist getting the air out crack the nut at the top of the fuel filter where the return lines end and pump the manual fuel pump to bleed the air out. When bubbles or hissing is absent, have someone crank the motor while you pump the manual fuel pump and it should fire.

imagesinthewind · #3 05-27-2006, 05:24 PM

(blonde moment coming, please be gentle)
Now let me make sure I know what you're talking about.
The spin on filter is the next filter the fuel goes through, right?
Its the metal one? My car has what I think is a plastic tube that comes
verticale out of the with a black plastic cap.
Is that the filter?
Thanks,

mikemover · #4 05-27-2006, 06:36 PM

Another technique to try is to loosen all 5 of the hard fuel injection lines, right where they connect to the injectors. Then use the hand pump on the side of the injection pump repeatedly... Pump it a LOT of times... to get the air out.

Re-tighten the lines, and the engine should start, assuming nothing else is wrong.

I've used this method to get several 617 engines that had sat dormant for a LONG time to start.

Mike

imagesinthewind · #5 05-27-2006, 07:52 PM

Ok, I've done that. Cracked the nut, pumped the pump forever tried starting.
I can get it started for a second. It uses all the fuel in the filter and it doesn't seem like the fuel is coming to the filter.
It's now empty.
Help?

mikemover · #6 05-27-2006, 08:38 PM

The screen in the bottom of your fuel tank might have clogged, since you ran it so low on fuel, all of the assorted crap that can accumulate over the years might have settled onto it...

Remove the fuel gauge sending unit from the top of the fuel tank, and use a flashlight to look in there and check it out.

Mike

imagesinthewind · #7 05-27-2006, 11:07 PM

Okay THAT's done.
What a F***ing B***ch THAT was!
How does anyone do that by the side of the road!

But, it's running again and I drove it around to help charge the battery.
I think Mike is right about the tank screen. While driving I found a lack of power for a few moments and then it would come back. That happened
a couple times and I think tomorrow I'll be asking how to take out that screen
and clean it!

I don't want to do that again!!
Thanks to all who helped me out there!

DougO · #8 05-28-2006, 08:14 AM

When you do clean & or replace the in tank screen it will be most helpful to have the tank almost empty and have have something to drain the fuel into. Unless you have something like a fuel caddy to siphon the fuel into. They use these in service facilities when working on fuel tanks.

Plus you have the possibility of taking a good diesel bath.

imagesinthewind · #9 05-28-2006, 12:17 PM

Okay, I'm awake and ready to go tackle the tank screen.
Ome problem, how do I get to it?
79 300SD, can I get to the tank screen from the top of the tank
or is it a drain the tank and get to the screen from the bottom
of the tank?
I kinda need a step by step (yes I searched and didn't find) in
order to help me. I haven't found a manual for my poor 116 as they
all seem to be for the 123.
Thanks to all who can help, I'd like to have this done by mid afternoon so
DH can drive it to work.

imagesinthewind · #10 05-28-2006, 12:31 PM

Okay, this morning I want to get to and clean the tank screen.
I've not done this and don't have a manual since my car is a 116
and manuals for that one are scarcer than chicken teeth.
Can you all help me with a step by step?
Where to get to the screen (from under the tank or through the top?)
What to use to clean it or should I get a new one? Dealer or NAPA for
that?

I'm getting a loss of power that isn't sudden but kind of like the car just
decided to take a nap. Doesn't stall just goes slow. I cleaned the in line
filter and spent too much time learning how to pump the air out of the lines.
But I still have the power loss and it's definitely a fuel starvation thing. Hence I figure it's the cleaner fuel I'm using and then allowing the tank to get low on fuel and the gunk gets to the screen.

Thanks to all who help me out, I'd like to have this done by mid afternoon so the DH can drive the car to work.

Thanks!

Biodiesel300TD · #11 05-28-2006, 01:05 PM

I'm not familiar with the 116s but on my 123 there is a big allen bolt on the bottom of the tank that is the tank screen. I needed a 24mm allen to get it out.

First make sure your tank is nearly empty.
Jack up one side of the car.
Drain any fuel that is left in the tank.
Unbolt the tank strainer.
Make sure you have something to catch fuel in, I garrenty you will leak some.
Clean the strainer with water, and make sure it is dry before putting it back in.
I would get a new O-ring for it, just so it doesn't leak when you put it back on.

imagesinthewind · #12 05-28-2006, 01:19 PM

Thanks Andrew!
I'll be under the car.. .

I did find a link to a place with some picks of what and where the tank screen
is located. Now I need to see if I have the right size socket.
If not, a trip to the hardware store! I love the hardware store!

Biodiesel300TD · #13 05-28-2006, 02:00 PM

If you can't find a allen to fit you can do what I did. I bought a bolt that had a head that was the right size or close, I had to file mine down to get it to fit. Then buy three nuts to fit on the bolt and wrench the nuts down on the bolt so you can wrench on the nuts to get the screen out.

Diesel Giant · #14 05-28-2006, 02:08 PM

On this pictorial I have some pics of where the fuel screen is.

http://dieselgiant.com/mercedesfuelhoseinstall.htm

imagesinthewind · #15 05-28-2006, 05:36 PM

So far this is what we've done (got my DH to get under the car, his very first time doing car work, I have a sunburn on my back and cannot lay on the ground).
We got the tank screen out but honestly it wasn't the tar mess that I was hoping for. It was pretty clean really. I soaked that to clean off what was there. We did have to drain 8 gallons from the tank.
I found a fuel leak in the longer line to the in line filter so I went and got new lines for that.I couldn't keep the car started this AM when we started and when trying the battery went really low so it's been on a charger for about 3 hours now.
So, the tank got emptied, the screen got cleaned, the filter and lines got changed. I pumped the fuel up to the spin on (my pump shoots fuel as I'm pumping, I'm sure THAT souldn't happen). Filtered the fuel and refilled the fuel tank. I haven't tried starting it yet. Want to let it on the chargers for a bit longer.
So, if it doesn't start what is my next step.

(When I went to NAPA for the new fuel line I was greasy and gross and one guy said it was nice to see a chick working on her car. . .)