I could use some help. I just got this truck, 1989 F250 4x4, 460, ZF five speed, dual fuel tanks and seem to have some fuel issues. First, the rear tank pump doesn't appear to function (I ran the front tank out, switched and the full rear one stayed full and I was dead in the water) I pulled the fuel lines on the selector valve with the the 6 ports on it that went to the rear tank and drained some really skunky fuel that I put in the front tank to get to a gas station and it started running poorly soon after. I figured it couldn't hurt to change a fuel filter but I can't find one on the truck. The supply line from the front of the selector valve goes to the high pressure pump and a line from it goes to the fuel rail by the distributor and the return leaves the rail by the pressure regulator and heads back to the selector valve. What am I missing? The diagrams I have looked at and component locators seem to place the filter right ahead of the high pressure pump but there is just a line there and nothing appears altered (funky splices,etc) I have done some searching on this forum but haven't found what I'm looking for. Thanks in advance, Abe
Last edited by capn_r; 05-16-2011 at 11:02 PM.
Update on progress (?) I wasn't getting fuel from the rear tank and I drained the nasty crap out of it. Since I don't appear to have a filter anywhere to be found I pulled the bottom off of the selector valve (the part that says "do not remove cup" on it) to see if it accidentally had a filter in it like some of the earlier / other models had and found nothing but a small o-ring in the bottom of the cup. I then hooked everything back together and put one of Harbor Freights finest pressure gauges on the schrader port on the fuel rail and lit it off. The highest pressure I saw was around 35 psig and it would drop to 15 or so and run worse then pick back up to the 35 or so and run fairly decent. Does anyone have part numbers for fittings to splice the hoses from the rear tank to the one's that supply and return from the engine? I can get by without the rear tank and just want to eliminate variables with the selector valve by taking it out of the loop. Do I have a high pressure pump failing or did I introduce an air leak? Thanks for any recommendations.
Thanks redmondjp, is that the kind where you cut the plastic hoses and clamp splicers in? I think my high pressure pump just died, you hear a pump for a couple of seconds when you turn the key on, it won't start and it holds about 10 psig. Wouldn't that mean there is power to the pumps but only the low pressure one in the tank is working? I do believe I'm going to do a barbecue juice (propane) swap a little sooner than I had planned. I have most all of the components to do the swap and I believe my ignition will work good for the bbq juice and I don't seem to have any ignition issues (fingers crossed) I don't have known good spares for pumps and selector valves and I don't want to invest in new stuff that would not be used in the fuel change so I guess it is time for the swap.
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