Pump Loosing Prime

[sparks57]

My injection pump is loosing prime when it sits over-night or while I'm at work, and stumbles a little when it sits for an hour.



What's going on here?



Three things have recently been done:



•AFC hose broken, held together by gasket shelac and teflon tape.



•Full fuel screw in 1/2 turn (now 2 turns from stock).



•New supply line.



Could any of those things be causing this? If not, what is going on here???

 

[bmoeller]

How's the lift pump? Any external fuel leaks? Fuel filter sealing properly?

 

[sparks57]

No visable leaks. The pump was leaking pretty bad out of the top where the supply line comes into the top but that was fixed with the new hose.



I'll look closer at the pump and fuel filter in the morning.



Could the bad leak at the supply line have stressed and messed up the lift pump? This only started AFTER those three things were done, so this started after the leak was stopped.



Thanks for the help!

 

[sparks57]

I checked a little closer and I can't, for the life of me, figure it out.



Any ideas?

 

[dpuckett]

I wouldnt think the AFC has a DANGED thing to do with the fuel flow. I ran mine w/o the hose for 2 or 3 months till I had the cash to buy a new one. Never had a problem, except it drove like a stock rig.



So, that leaves us with the supply line (likely source) and the fuel screw, which you just cant leave alone. Check the conections of the line, and see if there is anything leaking. AND if all checks out well there, you may have pushed the VE over its limit, and it's not holding due to some internal overstressing (you broke something again). Is this the Wonder Bread pump, or did you get your original rebuilt?



Daniel

 

[sparks57]

The problem seams to have remedied it's self.



Me, break someting??? NO WAY.



At least, I better not break it, this one's a loner!



Once I get some time to call the Pastor, a PDR performance pump is on the way! But finding time during business hours is tough!

 

[sparks57]

Ok, maybe not... still doing it.



Observations:

•Tries to catch when I first bump the starter (fuel in injection lines?).



•Primer pump lever does not respond until I crank the engine over a few times.



•Once I crank on it for a few seconds, the primer pump catches and I can prime the pump, then fires fine.



Any ideas?

 

[JLEONARD]

Primer pump lever does not respond until I crank the engine over a few times.

I would suspect the lift pump, or the integrity of the connections to the pump.

How old is the pump?

Jay

 

[dpuckett]

I would at least get the thing pressure checked. Mom's LP has to be just right for it to prime with the manual lever, so that in and of itself isnt too much to worry about. Seems like i remember reading his pump is fairly new, but that could have been some other kid.



I need to get in touch with the Pastor, but I also need the money before I do that. Danged Gestapo... ... . Worse than the tax man as far as taking money.



Daniel

 

[cerberusiam]

The primer on the lift pump will work or it won't. You are probably just getting it with the lobe up more often than not.



If it will consistently start fine after priming the lift pump there is a drain back problem. There should be a drain back valve some where in the system to hold fuel in the lines and it is probably leaking back after sitting. Could be worn or garbage in it. I think it is in the top part of the fuel filter housing but not sure.



Didn't you change injectors in the truck? It could be you need to retime the pump to take into account the higher pop pressures of the new injectors and the fact that is not the exact pump for that application. If it is timing you should be seeing a lot of white smoke on startup and until the engine warms. If no excess smoke it is probably a drain back issue.

 

[sparks57]

Hmm... thanks cerberusiam...



I'm not thinking it's the injectors because this didn't start until a few weeks after that... I'm thinking this "drain back" issue is looking warm... lemme poke around at my fuel system this weekend and I'll get back to ya.



Hey, that pump might be headed back your way soon, I just gotta get ahold of the pastor for a PDR pump.