'76 300D Need help identifying fuel lines

[stevebee]

I just had my mechanic install a GreaseCar Kit in my '76 300d, and I don't think he hooked up the fuel lines correctly because after about 60 miles, the car now won't start.

The Haynes manual is not very detailed, and I need help identifying where the fuel lines go.

The instructions that came with the kit refer to the output port on the diesel fuel filter, and the feed line on the injection pump. Can some describe where these are? The Haynes manual says there are two lines going into the injection pump.

What I see are (1) a fuel line from the very bottom of the fuel filter that runs to the injection pump; (2) a line that runs from the push-button that is attached to the top of the filter (I believe this push button bleeds air); and (3) a line from the top of the filter that I believe is the return line.

The GreaseCar kit has two 3-way valves. I suspect that the mechanic set it up so that veggie oil goes through the diesel filter, and I think it's supposed to go directly to the injection pump.

Any and all help appreciated. Thanks from a newbie!
--steve

[t walgamuth]

to me if he had them wrong it would have showed up as a problem right away.

tom w

[stevebee]

It's possible. The car became gradually harder to start over a period of a few days. I think it wasn't being purged of the veggie oil because the veggie was going into the diesel filter. GreaseCar says 30 seconds to a minute for purge, and I don't think the diesel filter could be purged in that short a time.

Is the line at the bottom of the diesel filter the input line? Is the line at the top that comes out of the "push-button" the outlet?

Thanks,
--steve

It sounds to me like there is air in the system somewhere. Unscrew the primer pump handle (on the side of the injection pump) and pump it until fuel flows out of it. If this doesn't work... let us know.

Here's one way to figure out the fuel line setup for the Greasecar system:

(1) Locate the fuel filter housing for the auxiliary tank (it is the one wrapped with a copper heat exchanger and reflective bubble wrap). There is a rectangular t-fitting box that has a radiator hose coming in (from the auxilary tank) on one side of the box, and white pex fuel line from the opposite side. This is the fitting where the HIH (hose-in-a-hose, the fuel line inside the radiator hose) splits.
(2) Follow the pex piping. Eventually, it should be fitted to a flexible fuel hose (typ. rubber), then hit a t-fitting, from which one hose should continue through the fuel filter, before attaching to the SUPPLY valve (solenoid) at the NC (Normally Closed) port.
(3) Directly opposite this port on the valve is the COM (common) port. If you follow this line, it should go to the lift pump on the side of your injector pump (IP, you will see a priming handle there). From there, the fuel line comes out the other side of the priming handle (to the left of it if you are standing on the driver's side of the car) and should feed the IP (in the back). The fuel is then fed into the injectors through the metal hoses from the top of the IP.
(4) Fuel that isn't completely combusted is returned through the black friction-fit return hoses (they have woven fabric on the outside, like the childhood finger traps) between the injectors. Follow these lines, and they should take you to the banjo bolt fitting atop the fuel filter. One line goes back to the IP and the other goes to the COM port on your RETURN valve.
(5) From the return valve, the NC fitting (again, directly opposite the COM port) should reconnect to the tee I mentioned before (before the aux. fuel filter).
(6) The NO (normally open) fitting should connect to the return line to the diesel tank.

Back to the supply valve...
(7) From the NO port on the supply valve (now going in the reverse direction of the actual fuel flow), the fuel line should connect to the original fuel filter housing (near the banjo bolt fitting you saw before), come out and pass through the primary fuel filter (a small plastic filter that typically has a transparent window) and attach to the supply line from the diesel tank.

Let me know if you need more info...

[stevebee]

Originally Posted by vwoodruff

It sounds to me like there is air in the system somewhere. Unscrew the primer pump handle (on the side of the injection pump) and pump it until fuel flows out of it. If this doesn't work... let us know.

My car doesn't have the primer pump handle on the side of the injection pump. There is a saucer-shaped device with a rubber push-button on the side of the diesel filter. Can I bleed air just using that little push-button?

The Greasecar plumbing is not exactly as you described. The return lines appear correct, but the supply lines run as follows:
1. Supply from the diesel tank goes through the small clear pre-filter to the lift pump on the side of the IP.
2. A line goes from the lift pump directly to the Greasecar supply valve normally Open port.
3. The supply valve Common port goes to the push button primer pump on the diesel filter.

The diesel filter has three ports as follows:
1. A clear line from the bottom of the filter runs to the injection pump.
2. The banjo bolt on the top of the filter has a.) a clear line going to the back of the injection pump; b.) a fabric-covered line going to the injectors; and c.) a new line going to the Greasecar Return valve, Common port.
3. The saucer-shaped gizmo with a rubber push-button with a line going to the Greasecar Supply valve, Common port.

This suggests to me that the diesel filter is full of veggie oil and that we have to run the purge cycle for long enough to purge the whole diesel filter. I don't belive that is the intent of the Greasecar system.

Thanks for your help, and any suggestions as to how to proceed!

--steve

Steve,

Do you have photos? From what you've described, it sounds as though there is no way for the VO to get pulled into your system. The lift pump should be on the other side of the supply valve. Otherwise, there is nothing to pull VO to your engine, which would jive with the problems that you're having. On my first install, I did the same thing, and my engine choked out because it wasn't getting any fuel.

With a lift pump, the plumbing should go....

diesel tank ----> primary fuel filter (clear plastic) -> secondary fuel filter (screw-on type) -> NO port on supply valve

and then...

COM port on supply valve -> lift pump -> injector pump

I'm not sure about this rubber push-button, but I would assume that it is a primer.

If you don't mind me asking, how much does a mechanic in Santa Cruz charge for a Greasecar install?

[stevebee]

I attached 3 photos. The supply valve common port feeds the line that goes into the push-button on the diesel filter. There is a clear line going from the bottom of the diesel filter to the IP. From this, I infer that all fuel goes through the diesel filter. I think the veggie should bypass the diesel filter.

In any case, it's been warm here, 70 degrees F, and I heated the filter and injection pump, and still couldn't start, so I'm thinking there is air in the system.

Or maybe the diesel filter is clogged with grease? But since it's been so warm, I don't think the veggie grease would have frozen.

--steve

[Palangi]

The older type of filters (like that one) have a drain plug near the bottom. Open up the drain plug and let it drain into a container. See if fuel or jello comes out. Put the plug back in and pump it up with the hand pump. (This may take many many strokes.) I actually prefer that type of filter over the newer (spin-on) type because you can easily let the krud out of the filter and see what's in there.

Yeah, there is no way that the VO should go through the diesel filter. Like I said before, I am unfamiliar with the push button near the banjo bolt, but I am sure that - if there is a lift pump - it NEEDS to be on the engine side of the supply valve. Switch that over, start the engine on diesel (pumping this button for a bit if need be), set the 3-way switch on purge for a couple of minutes (this will fill the lines to the trunk with diesel and push any air to the tank), and then switch to VO.

BTW... is there a line that runs from the bottom of the diesel filter housing? This config looks very similar to the '74 240... in that set up, the fuel line from the diesel tank went through the plastic, inline filter, to the fitting in the photo that you labelled "from COM port of the supply valve", through the diesel filter housing, out the bottom to the NO port of the supply valve, then the COM line went to the lift pump. Hope this helps...

[stevebee]

Hey, thanks for the replies. I will try draining the filter to see what comes out.

Yes, there is a line that comes out the bottom of the diesel filter. It's a clear line, and goes to the injection pump. Sounds like I need to cut that and splice it so it goes from the filter to the Supply Normall Open valve. Then the Supply Common line will splice into the other half of that and go to the injection pump.

I'm not sure I'll have time to do any work on it until the weekend. I'll let you know the outcome.

By the way, vwoodruff, you asked about what the mechanic charged. He charged $1000. I know that's a lot of money (!), but I have so little free time these days, and I just wanted it done. This was his first install. He did a neat and tidy job, and he fabricated mounts for the tank, too. (I can't believe that the GreaseCar kit comes with such a nice tank, and no brackets to hold it down.) I'm not too unhappy. But I'm not sure I want to take it back for him to fix, either! So, thanks for everybody's help here.

--steve

Sounds right on the new splice... and don't worry about the banjo bolt (I replied on the Greasecar board).

$1000, eh? Guess I've been charging too little! Of course, things are a bit cheaper out here. I lived in La Honda for a bit... man is it pricy out your way!