Where to begin? 7.3 IDI sitting for a year.

[marmot]

Well my boss was being a tool today so I took a long lunch and tried out the new mechanical lift pump, still have very low pressure, although there were a few air bubbles that came out of the return line fitting there was not much fuel. So probably a fuel pickup or fuel line problem I'm thinking. I am picking up my facet pump on friday so I will be running out of a can of diesel and if I can always throw a transfer tank in the bed and pull fuel from it I need to .

 

[79jasper]

Did you replace the rubber line at the lift pump?
If no, do it.

Sent from my SM-T537R4 using Tapatalk

 

[IDIoit]

replace ALL rubber lines!!! and for the love of the IDI gods.
PUT YOUR TRUCK IN YOUR SIGNATURE!!!

 

[marmot]

Did you replace the rubber line at the lift pump?
If no, do it.

Sent from my SM-T537R4 using Tapatalk

I am going to pick up 6ft of fuel line and replace all the lines on friday evening. A facet pump is waiting at napa and I am going to get the engine fired first. Then I will look at the ip and or hard lines and tank selector if there is an issue.

IDIoit there she is in all her glory, it is actually a pretty nice truck except for the fact it doesnt run of course.

 

[marmot]

Hey folks,
Got the facet pump installed and plumbed just need to wire the relay in the morning and it will have lots of fuel to the pump. I have a five gallon jug of fresh diesel ready to go. Keep your fingers crossed I know mine are.

 

[sjwelds]

Awesome keep us posted. I've been following with keen interest. Wish I was there to help and hear it crack off.

 

[marmot]

Well I had everything connected and the line in the fuel can and .......nothing....I left the key in the ignition and it was apparently in the acc position so batteries are totally dead now I am waiting for a charge and I'll give it a go.

 

[marmot]

Well I bled the filter until fuel shot across the engine bay there is no sign of air. The facet pump works great but still no fuel out of the return line fitting on the IP? SO I am looking at removing the pump cover? They appear to be T25 fasteners. What should I be "exercising" in there? I think I have an idea on reassembly but any links to a "how to" on this would be greatly appreciated. Also how can I determine that the pump is not ruined. So much for my daydream of firing this thing up and driving it. I however am not a quitter so I may be looking to ya'll for some junk yard shopping. Our 1 local scrap yard is not so hot.

 

[marmot]

Just sipped a glass of rye and got to thinking which, I am told, can be dangerous. am I correct to think this has to be the fss or the ???? which the fuel shut off lever acts upon. I am assuming that the return line fitting should have fuel flowing thru it when the e-pump is on and the fss is "open" or does the IP need to rotate for fuel to flow thru the return line fitting? Thanks

 

[bbjordan]

I think the pump needs to be turning for the fuel to flow thru it. The Fuel Shut-off Solenoid normally holds the metering valve closed (no power to it). When there is power to the FSS it allows the metering valve move to do its job. The little black fitting on the pump cover has a spring loaded check valve in it and will maintain some pressure in the case, but will open when the pressure is exceeded (normal operation). The advance plunger/piston is moved by the pressure difference between the transfer pump pressure and case pressure. The cold advance solenoid has a little plunger that opens the check valve in the black fitting. This lowers the case pressure and allows the advance plunger to move advancing the timing.

If you have the top cover off you may want to see if the metering valve moves freely and is not stuck.

Here is a pretty good video explaining how the fuel is routed:

https://www.youtube.com/watch?v=veEONfhL3Uk

I also commend you on your spirit (not giving up)!

 

[marmot]

Oh man that is great, thanks for the video! Thats gives a lot of insight as to what might be wrong. Is there a way to ascertain whether the shaft is turning? I guess you'd have to remove the side cover look with a mirror?

 

[bbjordan]

I guess you'd have to remove the side cover look with a mirror?

That is probably the easiest way. I would crank the engine a bit first to see if fuel is coming out the return line.

A fair amount of fuel will come out the when you pull off the side cover. You might want to put a shallow can or something (rags) to catch the fuel.

 

[marmot]

Pulling the IP this morning, just have to run and grab a 16pt 5/16 socket cause the bolts are too tight to move with a box end. I am a bit disappointed that the new pump is the issue but thats the way it rolls some times. When I pulled the top of the IP I found no fuel, completely dry! I can move the metering valve with no trouble and held it wide open and the cranked for 2min and no fuel in the housing at all. So I am guessing it is either not turning the shaft or some other issue, I don't really know maybe stuck veins on the inlet pump or some such.

 

[marmot]

I have the pump out it is brand new and spins freely and I can see the shaft is turning through the adjustment window, there is no diesel in the pump adjustment window either. Is there a method for bench bleeding these pumps?

 

[Shadetreemechanic]

Have you checked for obstruction in the fuel line between filter and IP? The ip shouldn't need bench bleeding because the return line system should allow air out the top as fuel goes in.