Well, it is finally done. What IT is:
I had plumbed the VP44 return fuel into the aux bed tank. Problem is the gravity feed will not keep up with the VP44 at cruise speed and it starts filling the aux tank, not good, scratch that idea.
I had not connected the OEM and the aux tank vent lines (actually the roll over valve on the OEM tank) and had some seepage there. So I plumbed the roll over valve into the aux tank vent. No seepage.
I could not find a aux tank cap that would not release pressure as needed until the pressure built up several pounds. You know the sticker on the cap reads (Remove this cap slowly as pressure might have built up). I tried several "vented" caps and they all built up some pressure. So I carefully drilled a 1/16" hole just about 1/16" below the locking tabs on the aux tank so the tank could vent as needed. It does.
Then I plumbed the aux tank into the second port on the draw straw. When the Vp44 return line went under the fuel level as the aux fed the OEM tank the VP44 would throw a 0602 code. Was very repeatable. So I ordered the "diesel gravity feed shutoff valve" from Northern Tool. Tommorrow is the first day of that test. We'll see.
Today I finally dropped the tank to fix the fuel level sender. My error on install last time is I should have had the sender arm swinging forward. I had it swinging aft and it hit the top of the OEM tank and that stopped it at 5/8 tank full. So I turned it around BUT I also replaced it with a 14" Tempo sender because the 11 3/4" one left like 6" of fuel in the bottom at the "low fuel" indicator. I installed the 14" one today and measured the totally empty at 1/1/2" of fuel. The 1/8" to go (ie low fuel light) will give 3" of fuel. I also changed the mounting a little and will get into that.
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07/03 Update
OEM tank is full, DC gauge reads full, needle is right over the F wide red mark. Exactely where it should be. So far so good, resistor value is verified good.
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So, where I am is the aux is filling the OEM as we speak through the Northern gravity cutoff valve. It seems like a slow process, and I have to evaluate it to see if it keeps up with the injectors (dd2's) I figure about 13. 5 gph (Vp44 rated at 45 gph 70% goes to cooling (ie back to the tank) which leaves 30% of 45 gph for the injectors = 13. 5 gph)
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07/03 Update
Northern tank cutoff did indeed cut off when OEM tank got full.
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Now the details of the install with pics if I can figuer how to upload them.
The gauge is the TEMPO 420060 14" model. Larger swing than before and on the step of the OEM tank it actually is about 14" deep. It comes with the same kind of float that DC uses.
I used a Roberts MFG PF26 3 3/4" x 1 1/2" (You have to order $20 at a time for a cc order. The floats are like $2. 50 each, so you get like 8 of them in an order. So we need to let who has them and who needs them get together.
Cut the float off the Tempo 420060 at the 3 1/8" length from THE GEAR MECHANISM end on the 420060. Hold the PF26 up to the unmodified float arm, match the bottom of the PF26 to the end of the unmodified arm. Mark where the top of the PF26 is on the unmodified arm with a sharpie. Then ADD (go toward the unmodified arm float) 1/4" for the threads that will go INTO the PF26. Mark where you are going to cut the unmodified arm. MEASURE TWICE, CUT ONCE. Cut the unmodified arm. Thread 1/4" of 8/32 threads onto that extra 1/4" you allowed in the previous step for the float to thread onto. Thread the PF26 onto the arm of the 420060 until you have used all the threads (you will unscrew the float when you put the gauge in the OEM tank, and re-screw it on from inside the OEM tank). Now there is a tiny bit of mechanical interfearance of the float and the stem of the 420060. It is at the full reading so it should not matter. I will know in the morning.
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0703 Update
When the tank is full the OEM gauge reads exactely full so the mechanical interfearance does not inhibit the OEM gauge from reading full correctly
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Order a Stewart Warner 366LP-F Fuel Level mounting kit (~ $25). What this gives is a plate to screw the screws that go through the 420060 into as well as a second gasket on the tank side. The 42006 comes with a gasket for the outside of the tank. The 366LP-F will add a gasket to the inside tank side. I have not found any "goo" that will actually leakproof the tank yet. I have tried several Permatex products, but the diesel just eats them, or will not allow them to stick.
The screws that come with the 420060 are too short. I used 10-24 x 1 1/2" stainless steel screws. You will need to recut (tap) the threads on the 366LP-F to the 10-24 thread. The threads of the 366LP-F are just about 10-24, so it is not a radical change.
KEY POINT when you drill the OEM tank for the gauge MAKE SURE THE GAUGE IS SWINGING FORWARD.
Just forward of the canister part of the tank is a step raised up some. DC puts a vent line there in gasser tanks. I mounted the gauge there. Nice little platform, flat, is raised surface a little just for a "device" enough room etc.
I did not cut the center hole for the gauge mechanism any larger than I needed (about 1 3/8"). Remember the float is 1 1/2" in diameter? You are going to do the arm shortening and and cut the threading and then thread the Robert's MFG float PF-26 onto the arm AFTER you mount the gauge and get the gauge all sealed up. You are going to have the canister out and you can get your arm in there just fine. I had to get my arm in there almost to the arm pit to hold the 366LP-F and gasket with one hand as I was installing the 10-24 1 1/2 screws with the other hand.
KEY POINT when you drill the holes for the screws DO NOT UNDERSIZE THE HOLE for the screw. I did and the problem is the screw actually taps into the tank material and does not have any freedom to go into the receiving screw hole on the 366LP-F. I fought that for about 2 hours and then enlarged the screw holes in the tank material to 1/4" and then it was easy to assemble the gauge, gasket, tank, gasket, 366LP-F.
You do not want to strangle the gasket. Good and snug or it will distort if you apply too much torque to the screws. Good and snug, not strangled.
Make sure you swing the float through out the full range. I found that there is about 1" of clearance of the end of the float and the forward part of the tank platform slope. I measured the fully verticle float at 1 1 /2" of fuel. I measured the 1/8 tank remaining at 3" of fuel. Right about where we want it.
While you are in the tank (literally up to your arm pit) clean out any little shavings you might not have collected during the install. I found if you close your eyes and concentrate on your sense of touch you can retreive anything grainy of unusual feeling. I also used some paper towels to wipe out "residue".
I drained the tank by hooking a siphon hose to the draw straw fitting and siphon until it went dry. That will also tell you what is left (fuel level) after your draw straw runs dry. Of course the truck should be fairly level when you do this. Mine leaves about 1/4" of fuel in the bottom of the tank. The tank is still fairly easy to control when uninstalling it or installing it. Weighs about 20# but is a little awkard in shape.
Ok now you have to get the mechanical gauge to talk to the DC canbus. We talked before about using a 2700 ohm parallel 1 watt resistor across the DC canbus wiring. Well Tempo makes a "remote gauge capsul" 420110. One nice thing about the capsul mounting on the outside of the tank, you should NEVER have to go into the tank again EVER. The capsul electrically reads the float arm position and with the 2700 ohm parallel resistor the industry standard 35 - 240 ohm will be adjusted to the unique DC 20 - 220 ohm canbus.
If the remote capsul ever goes bad, replace it, it is on the outside. DO NOT HAVE TO GO INTO THE TANK AGAIN. Another nice thing is when you drop the tank if ever again, just unscrew the capsul and your electrical connections to the capsul never have to be opened of unplugged or anything. It is a ONE time thing. If you screwup the threads that hold the capsul then you have to "engineer" that fix.
I'll put pics in the next post so I do not screwup this post.
I feel really good about it. Mechanical float mechanism that can survive boating, float that can survive harsh chemicals, all enclosed. Remote reader adjusted for the DC canbus and this fuel level thing should be done once and for all.
Bob Weis
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