bwdozerman

Cleaned all the check values in the pump. Pump outlet valve was limited most. Crossover passage has pressure relief valve back to pump inlet. Cleaned that as well. Engine started right up and ran good. Just sitting too long seems to be what caused the problem.

I'm sending from my laptop, so it might not show up the same. Before I put the lift pump back in, I want to clean and check everything in the crossover chamber to ensure nothing is hung up in there. Fuel does get into the inlet side of the lift pump, but, not to the outlet side. Let me know if you are aware of any precautions I should take before opening this up. Attached photo for reference. Thanks,

I'll try blowing air through the lines, but, it seems the problem is internal to the lift pump. Thanks,

The idler gear isn't worn, and only has a very slight backlash. Seems fine. Hand primer easily pulls fuel from tank to pump. Fuel just won't go from pump inlet to outlet. Can the passage be opened and cleaned to unstick, or does it need specialized rebuild? Any ideas on a source for a replacement? Thanks,

Timing checked out to be ~19 to 20. Hand primer pumped up tight, but, no return flow to the tank. No return flow to the tank while cranking either. Removed lines to lift pump. Very obvious that no fuel at all is passing through the pump. I don't have any idea of how the passage from inlet to outlet works. Most likely springs set to control precise pressures. Something must be seized to prevent all flow. I turned the motor with a bar and the pump gears do turn. What's the best repair strategy? If I go to the Mack store, they'll most likely not be able to look up or supply a replacement. Thanks again,

I removed the fuel return check valve. It shuts off good and has appropriate spring back pressure. I will try the ether like you suggested. There is no smoke at all when cranking, making the fuel supply issue likely. Please say exactly where the fuel lift pump is located. I was thinking it was inside the injector pump, like a farm tractor. Thanks,

Pump drive gear turns when cranking.

I cleaned up the area and remove both screw caps and the timing cover. Rack moves freely. Pulls all the way in when fuel shutoff lever is rotated to shutoff position, and pushes out when throttle lever is rotated. The hand primer lifts fuel easily through the filters. After cranking to start, it seems like the hand primer pressure is lower. There is no external lift pump on my truck, that I can see. Is there a way to check the low pressure lift pump section of the Ambac pump? Maybe it's something else. Thanks,

Are the screw caps that expose the fuel rack on either side of the timing cover? The tachometer is connected to one of them. The throttle lever pivots freely, but, doesn't appear to be moving anything internal. Stopped by the Mack store to try and get an exploded parts view, but, they couldn't get anything off their system. I haven't actually opened anything, just took the photos below. The fuel inlet has the silver fitting, mabe a check valve. Let me know what to open to expose the fuel rack. Thanks,

Excellent! I'll check this out on Friday.

The throttle shaft turns OK. Maybe it can disengage from the rack. I'll loosen a few injector line nuts, but, don't expect to see fuel. Everything seems fine, except no fuel into engine.

I'd love to hear the '59!

Is there any kind of electrical shut-off for the fuel transfer pump? I'll check out all y'alls tips. When the motor lugged down to stall, could it have turned the injector pump backwards? There may be a check valve right at the pump. It's a little wet with fuel now. Maybe forced shut to hard. I'll look it over Friday. Thanks again!

Mine has the "V" injector pump. I did stroke the fuel shut-off lever, and it is normal. The motor cranks normally. It just acts like it's not getting any fuel, which it isn't. I was thinking the drive gear to the injector pump may be damaged, or something else inside the pump shifted. The starter can move the truck easily, which makes me think there's no mechanical damage. The hand primer pump doesn't seem to circulate back to the tank freely now. Any thoughts? I thank you for your reply.

1987 Superliner w/e9. Engine was running fine. It sat for a couple of years and the clutch was stuck. I pulled it into gear and it moved forward and stalled. Now, it won't start. Acts just like the fuel shut off is closed. Could the injector pump be damaged? Any ideas are appreciated. Thanks