Trying to diagnose air or ip

[id_bowhunter]

84 ford w 6.9.... I am banging my head against the driveway I have used clear hose from tank to lift pump, lift to filter, filter to ip, and return back to tank. Very minimal bubbles in size and consistency questioned lift pump pressure for $30 I figured wth change it. Here is the problem even with new lift pump idles ok at high rpm after 30-60 seconds it jumps to higher rpms and starts acting like there is no fuel drop it back to idle and it surges a few times and levels out or dies not sure what fuel pressure is thanks to small a** shcrader tanks are over half full my front tank has the usual problem with the pickup tube all injectors are working i did the crack the cap test I'm new to diesel motors any help would be great thanks

 

[John Deere]

If I am understanding correctly, these symptoms are at idle. How does it act with a little throttle?

 

[dgr]

You want clear hose on the IP return to the fuel filter. From the number one injector to the filter head.

My 86 has a tire valve size shrader where I can pull the fuel pressure. If you don't have access to the proper adapter, A can of fix a flat has a tube on it that should depress the valve. An extended valve stem with the top wedged open will do the same or the easiest is to unscrew the core and use a piece of hose and "thread" it onto the schrader.

My engine wasn't showing any bubbles at idle but if I revved it up and let off, it would show them. I suspect it was the fuel water separator so I plugged the hose.

Finally, please try some punctuation. Your world record run on sentence is a bit difficult to read.

 

[id_bowhunter]

After start up idles normally
High rpms 30-60 seconds it starts to flutter and puff white smoke intermittently
Let off throttle it will surge for about a minute and return to normal idle/ of fall flat on its face and die

 

[dgr]

And you changed the fuel filter? When it dies, can you pull the fuel filter and see if it is full of fuel?

 

[John Deere]

I had an 84 that acted the same way, I ran it for 8 yrs and 30,000 miles that way. Assumed it was the IP, but the pickup got totaled just before I was going to change the ip.

 

[icanfixall]

I believe your filter is dirty and needs to be changed. Your engine sounds like its running out of fuel and your fuel lite is not connected or working.

 

[id_bowhunter]

Replacing the filter was the first thing I did. Second I changed the lift pump, still no change. I did talk to a local shop they suggested clear hose on return side of ip, also they said to try running a hose on the supply side of ip into a gas tank w/ diesel to see if it was blocked supply or lift pump.

When I run the hose on the return side it idles all day long, but when I put throttle to it it starts showing bubbles , then starts to foam, then dry and die. I haven't had a chance to try the supply side yet

 

[id_bowhunter]

To the filter question it was half full a couple times but on all tests since lift pump change it has been full or at least to the bottom of the threads

 

[dgr]

Stick a bolt in the hose hanging under the front of the drivers door in case you are sucking air through the bottom of the water separator.

Take the fuel line off the lift pump and put it in a 5 gallon can of fuel. That will tell you which direction you need to search for the air intrusion. Make sure your tank isn't full as you will be returning all that fuel to it.

Am I reading correctly that you ran a clear line from the tank directly to the lift pump and saw bubbles there? That would suggest to me the fuel pick up has a crack. Kind of baffling as it seems what you are describing is an air intrusion our lack of fuel

 

[id_bowhunter]

I haven't had a chance to try the supply side of tha ip yet. The shop told me to do what DGR suggested but to disconect line at filter head outlet to inlet side of ip and run out of the gas can w/o lift pump to determin it's not the injection pump . I know the h20 separator is not stock it has a white plastic cap that is threaded and seems like it is a plunger you can pump up and down after it is unscrewed but I will give the bolt thing a shot.

 

[dgr]

That is a cool sounding separator.

Make sure that fuel I'm the can is clean. There is only a screen in the nose of the ip to trap anything

 

[redneckaggie]

do a volume and pressure test on from the schrader and change the filter, check for leaks or worn hose. Just because their is not a leak does not mean it isnt sucking air somewhere.

specs for volume and pressure test can be found if you search google for intellidog idi.

 

[redneckaggie]

http://www.intellidog.com/dieselmann/idi.htm

this have volume and pressure specs and is pretty helpful. I have chased air intrusion on a couple trucks where we just said screw it and ran all new suction hose and return hose because it was such a pain, make sure to rule out the selector valve on the frame rail

 

[id_bowhunter]

The fuel filter has all but a half hour time on it since I replaced. I did notice though that I am getting black floaties in the return side of the pump. I am suspecting pieces of the two piece weight retainer spring, so I'm borrowed time w/ the ip anyway but when I do that I'm going to replace all the lines too. Just to rule out blockages and leaks.