i just installed new IP after checking the usual suspects-filter, lift pump(electric) fuel linesfor problems, found none figured it must be IP. so new pump in everything reconnected aaand no fuel to the injectors. fuel at schrader valve, fuel in return lines, just nothing coming out of injector lines, so WTF- where's the fuel? any ideas?

 

it takes a lot of super fast cranking with new cables,new 850 cca's and perfect starter.about 2 to 3 crank sessions each lasting 15 seconds (with 2 min starter cool down between.)
how long have you been cranking?
about to have this fun myself tomorrow,after adjusting the fuel screw.i never mess with injector lines.i just crank,cool,crank,cool,crank and she's running.
least with chip truck.here's to hoping log truck isn't any pickier lol.

you've got power to the fss? working glow plugs? smoke from tail pipe?

 

fss working, gp's good, no smoke. I'll play with it tomorrow after work

 

Loosen 2 or 3 injector line caps a turn or so and crank until theres fuel coming out, tighten em up and let her rip. Does take some cranking to get the IP filled up and fuel into the lines. Would be forever cranking without bleeding some of the air out.

 

I'm having exact same problem. I personally replaced glowplugs batteries and lift pump. Bled system by cranking a couple times then loosened line on top of injector pump and pushing needle on shrader valve. Couple more cranks got it running. But system filled with air again during test drive. Seems to want to idle just fine. Took it to mechanic and he diagnosed. as bad injector pump. Replaced. Still the same. waiting for more...

 

IT'S ALIVE! I thought maybe I didn't have enough fuel in the tank, so I turned on the electric fuel pump and left it running while I went to gas station. got back 15 minutes, cranked it twice and she fired right up!! and I didn't even put the extra 5 gallons in the tank woohoo

 

the schrader valve is on the drivers side of the fuel filter, I'm not sure which line you are talking about on top of the pump. there is a return line going into the top of the pump to cool and lubricate it. best way to bleed system in my experience is to loosen at least 1 injector on each side and crank 20 seconds and cool down 2 minutes. search "Installing IP" on here or start a separate thread. I knew nothing about these trucks when I bought this one and now I am my mechanic. 2 hours to remove and install my 2nd new IP. first one took three days. This site taught me everything!! Good Luck

 

you're right, the schrader valve is indeed where you say it is. I had tons of air coming out there. and I also opened the return line to top of injector and tons of air come out there too. my mechanic says that excess fuel flows OUT of the inj. pump there at the top, not IN from return line for "re-use." that's how I thought it was working until he straightened me out. the fuel return system is low pressure, so it probably isn't drawing air, otherwise there would be an obvious leak. my 2 pumps are brand new, there are no leaks under truck. so where does fuel go? and how does air get introduced? im suspecting the tank switch. the front fuel tank is very empty and the rear tank is brimming full. I usually keep SOME fuel in both tanks but when the truck went down I was short on cash, and had run the front tank close to empty before switching to rear tank. I filled rear tank to be sure there was some fuel in truck. put 9 gallons in till it wouldn't take anymore. if that tank switch is messed up and drawing from both tanks at the same time, then an empty tank would be introducing air into the system. I thought of this and went by shop and put 4-5 gallons in front tank as a troubleshooting measure. if it runs now, I know tank switch is bad and can replace it.

 

Return line fuel goes back to the fuel tank through its own fuel line.

Air enters the fuel system anytime it is "open", such as replacing fuel filter, lift pump, etc or from a leak anywhere in the fuel system, from the tank to the injectors. Cracks in the fuel line are a common place to develop air leaks. Also from an improperly installed fuel filter.

 

It was the tank switch. not sure if it was doing what i thought. mechanic said he ran some tests with switch still in place and noticed something wasn't quite right. he pulled it out and bench tested it and it wasn't working right. he also mentioned that those switches did all sorts of strange things over the years he has worked on them. Truck is temporarily plumbed to rear tank only and is running good. new aftermarket switch on the way...

 

Freddyack...fyi... fuel return line goes to tank switch, not directly to tank on my '86 model.