Ford 7710 won't run

[DR7710]

I bought 1989 Ford 7710 and it was running great. I bought all new filters, but before I could replace them it quit running. Started out as a sluggish throttle, but then one day it would not start after I turned it off. I pulled the sedimenter and fuel filter and they were about half full of a thick sludge. So at that point i decided to pull the tanks too and clean the whole system. The tanks were in good shape but about a half inch of the same junk in the lower tank. Cleaned the tank and lines and put on the new filter. I did not do anything to the lift pump or injector pump. Filled the tanks with new fuel and started priming the system. I thought I had finished priming it this past weekend, but still wont run. It will act like it is starting but die in about 3 to 5 seconds. It actually ran about 15 seconds at one point but died then as well. With just turning the engine over I'm getting light puffs of white smoke. When if fires and acts like its going to run I getl big puffs of black smoke. So my question is, does it sound like I still have air in the fuel system or does it sound like I have another problem going on?

Thanks,
Doug

 

[Tx Jim]

Which type inj pump(inline or rotary)? If rotary check to see if check valve outlined in red is stopped up.

 

[DR7710]

Tx Jim, here is a photo of my injector pump. To be honest, I haven't dealt much with these injector pumps so you will have to confirm what I have. I'm thinking it is a rotary???

 

[DR7710]

Which type inj pump(inline or rotary)? If rotary check to see if check valve outlined in red is stopped up.

I pulled the valve this evening and checked it. There wasn't any trash in it. Looked clean. The ball and spring operated freely. Any other suggestions?

Thanks

 

[BAP]

I would suspect the lift pump. Are you using the hand lever on the side of it to prime the injector pump? If so, does it pump well or weakly? Also, check the engine oil, does it smell strong of diesel fuel and thinned out? When those lift pumps go, they can let fuel into the crankcase. Also, if the has the cable operated shut off, make sure the cable is pushing the lever on the injector pump all the way back like it is supposed to.

 

[DR7710]

BAP, thank you for the help.

Is there a way to check the lift pump, or do I just have to take it a part and rebuild it?

I started using the hand pump on the side of the Sedimenter/fuel filter body, but that got old quick. I filled the upper tank with fuel and as I cracked the vent screws I let gravity fill the sedimenter. I then used the hand pump to fill the fuel filter and get fuel to the pump. I then cracked the lines coming out of the fuel injector pump and turned the engine over a few time until I go fuel dripping out. I closed those lines then cracked the lines going into the injectors. I turned the engine over again until I got fuel without air bubbles coming out. The hand pump is now very hard to press where as when I started it was very easy to press.

I will check the oil the next time I'm out there. It does have the cable shut off. I checked it earlier, but I will check again to make sure.

Update: After checking that check valve, I tried starting it. On the second attempt, it started and ran good for about 30 second. Stopped smoking and was running pretty good with no throttle hesitation then it just died. Went back to only sputtering for a few seconds then dying. Not sure if that tells anyone anything, but thought I would add it just in case.

Thanks

 

[DR7710]

Also, check the engine oil, does it smell strong of diesel fuel and thinned out? When those lift pumps go, they can let fuel into the crankcase.

I finally got back out there tonight to check the oil. The oil was at the right level and did not have a strong smell of diesel at all and it is not thin. If I try really hard I can get a very slight hint of a diesel smell, but mostly it just smells like oil.

Any thoughts? :anyone:

 

[Rocky Hoffler]

It sounds like you still have air trapped in system if bleeders are present on filters open and see if fuel flows out if not start working lift pump handle and see if it will pump fuel to filters if there is very little resitance when pumping handle it should get harder to work when pumping fuel with no air. when you are satisfied that filter is full then move to injection pump if it has bleeder open and pump handle on lift pump to you get a good flow of fuel. close bleeder and try cranking if no start crack inj lines at inj and if has fuel tighten line. there is very little flow while working pump manually so it takes a long time to purge air. if you have bleed system take air filter out I use spray silicon start spraying this in intake while cranking give it a little throttle if eng starts and runs on its own run for a while to make sure all air is purged from system. Good luck

 

[banjodunn]

G'day does the top of your lift pump have a removeable cover if so then you should find a screen in there that could be blocked


Jon

 

[sixdogs]

Sounds and acts like air in the system. Something must not be bled right or is loose or something like that.