Sucking air..

I'll check that here in a bit and see. The supply line to the injection pump ts for a dual feed to the injection pump and on the t there's a plug. It still bubbled air out after I changed the airdog motor. The dual feed kit uses push lock on the 3 hoses. I'm starting to think I've got a crack in one of the rubber fuel lines.


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Ok, It builds fuel pressure as soon as the key comes on


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Changed overflow valve back to a stock one and didn't fix the issue. I did turn the airdog on and it had fuel coming through the overflow valve right away.. ?


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Run your suction line into a bucket of diesel to help eliminate the sump.
 
kole32 said:
Northern Indiana


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If you were closer to Columbus I would say come on down. If you are actually getting air it's pretty easy to eliminate. Remove line from sump put in buckets to suck from. Put a sight class in supply line at pump. Run unit. If still air you have not found the problem. It will only be sucking air on the suction side before the air dog. Another way to determine air is submerge the line at the pump and check for bubbles. It's a dirty not fun process but each part needs eliminated
 
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Thanks, I'll do that tonight, i just found it strange that when I had the overflow Valve out, I turned the airdog on and it pushed fuel out right away.


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Ok, I put the fuel line off the sump into the bucket, had a buddy turn the airdog on and I watched the 2 feed lines for the injection punp go into a bucket. The one line pushed fuel and the other didn't,Until I stuck my thumb over the one that was pushing fuel.


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Only time it pushed fuel out of the other line was if I stuck my finger over the line that was pushing fuel


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kole32 said:
Only time it pushed fuel out of the other line was if I stuck my finger over the line that was pushing fuel


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That's a problem you need to figure out why it's not moving fuel
 
I hooked up a single line to it, gonna see what happens


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97rada said:
That's a problem you need to figure out why it's not moving fuel
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Why is this a problem? You said you have the 40psi spring. It puts fuel out the IP supply line ONLY UNTIL the fuel pressure on the supply line reaches 40psi then it sends fuel through the return line back to the fuel tank. When you put your thumb over the IP supply line the fuel pressure overcomes the spring and sends fuel out the return line. This sounds to me like it's working properly. You need to check the fuel pressure in the IP supply line with a 60psi gauge to see what your fuel pressure from the AirDog to the IP is. It should be @ 40psi.

From what you initially said, your problem was that the AirDog was pushing air into the sump. Did it push any air into the bucket from the line that hooks to the sump?

Hook the IP supply line back up. Run the return line into an empty bucket and put the line to the sump into a bucket of fuel. Start the truck.
  • How does it start?
  • How does it run?
  • What's the fuel pressure in the IP supply line?
  • Is it pumping fuel out of the return line into the empty bucket?
  • Any air out the supply line (the line that goes to the sump)?
  • Any air out of the return line going into the bucket?
 
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I am out. To many hands in that lol if you stil can't figure it out pm me and I will give you my number. I do this stuff for a living
 
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No air was pushed back into the bucket.. I'll get a fuel pressure gauge tomorrow and check that, right now I have fuel in a bucket being sucked from the airdog to the injection pump, I took off the dual feed lines, I'm gonna see if it starts on its own. I


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97rada said:
I am out. To many hands in that lol if you stil can't figure it out pm me and I will give you my number. I do this stuff for a living
Click to expand...

Sorry if I offended you Austin. Not what I was trying to do at all. I've done this stuff for a living, too. Is there a flaw in what I posted?




kole32 said:
Ok, I put the fuel line off the sump into the bucket, had a buddy turn the airdog on and I watched the 2 feed lines for the injection punp go into a bucket. The one line pushed fuel and the other didn't,Until I stuck my thumb over the one that was pushing fuel.
Click to expand...

If I'm understanding the above quote correctly, we may have found the problem.

Kole, how do you have the two lines that come out of the same end of the AirDog run? Do you have both of them running to the injection pump?
 
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No, I have one line to the injection pump and one is to the return Into the tank, the other is from the tank to the airdog, I have a Vulcan dual feed kit, and it tees into 2 feed lines to the injection pump, when I put the supply line in the bucket and turned the pump on, only one of the 2 lines was pushing fuel to the injection pump.


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