1987 - 1996 F150 & Larger F-Series Trucks1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks
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Fuel over flow problem...check valve/selector valve??
Ok...I know this subject has been beat to death as I have done a couple of searches but I am not certain if "my" problem" has been answered and I need some help!!
I have a 1995 Ford F150 (302) with dual tanks...
The other day I was driving and noticed a fuel smell...I get out and open the hood...look around and notice fuel on top of the charcoal canister...I was like that weird??? I didn't over fill my gas tanks???
Pull vapor line of canister and the whole thing is full of fuel...great...I'm thinking the purge solenoid is bad...I call dealer for part and its coming...
So I decide to leave vapor line off to drive the truck around...next day I smell gas again...open hood....and see some fuel coming out of vapor line??? Huh??
So now I am thinking its not the solenoid anymore...something else...
I go and open the front gas cap....lots of pressure release....
Then I go and open rear gas cap....and lots of GAS comes out! Way overfilled!
So that's what is making gas coming out of vapor line up front!
Now I realize when I have the tank switch set on front tank the pump must be feeding some to the rear tank too...I thought my fuel mileage was taking a dump but in reality some fuel from the front tank was being sent to the rear...
So what exactly is my problem??? The "cross flow" problem appears to be only for 93 trucks with the mechanical style selector????
Since mine is a 95 I am assuming it probably is the rear fuel pump?? Or is there a check valve inline somewhere???
Would I have to buy a whole new pump or can I just purchase a check valve??? Are these dealer only parts or are they available at Autozone/Oreillys??
Any and all help would be great! I don't want to have to buy a bunch of different parts if I don't have too...
Well, misery loves company. I'm having the same problem, the front tank pumping fuel into the rear, that is. I don't have the other problem but I always keep switching tanks to keep the rear from overfilling. I've researched the possible causes but noone can answer the central question, is it the rear check valve ONLY that failed or has the front valve stuck shut forcing the rear open? A little knowledge on how the system operates is in order. The whole system is Tee'd. When you actuate a tank, the fuel pump in that tank is turned on and the pressure pops open the return valve to allow fuel to return to that tank. I know the rear's broke. What I don't know is: is the front valve stuck shut. If that's the case and I replace the rear FDM (fuel Delivery Module) it will just break again. No one, including the Ford garage, can tell me how to check the front unit. The valve is supposed to be closed with no pressure, so even if one remove's the front FDM, the valve would be shut, which is normal. I don't how one would pressurize the FDM to check the valve. For now, I just live with it. Of course, just replacing both units blindly would probably cure it, but I'm not that desperate yet. BTW, from what I've heard, if you want to do this, people seem to think it's easier to remove the bed to access the tanks than to drop the tanks. I think I agree. If you come across anything I'd appreciate a post.
Ya i'd say it's easier to remove the bed than drop both tanks. The bed is 6 bolts, two filler necks, a little wiring for the brake lights, and it comes off pretty much. It's the fact that ya gotta have a few extra guys handly to pick it up, 3 people can do it, 4 is better.
I couldn't tell ya which check valve is broken, but the FDM has the pump, sending unit, and check valve in it...so ya gotta replace it as a unit, which isn't too bad because you should probably change all of those items while you're doing this anyway...the pumps go bad after 100k just like most things anyway. So if it were me, I'd pick a day to do the job, take the bed off, and swap out both of the FDM's. You can get them at any local parts store. I looked at one from autozone, and it used a walpro pump, which is good, but I prefer Napa they seem to have better parts on average.
could be you need a cross flow check valve added to your fuel line. There were recalls for this on 94's. See alldata.com, TSB's on the left and then find your year 0of truck at ther bottom of the page. On my 87 it was cause d by a fuel selector value going bad. Look up recall because sometimes it builds up pressure to in the tanks. Haynes says if FDM intank fuel pump is bad you need to replace it , no repair kits for a stuck valve inside pump .
In the late 1980's Ford had a recall on E150 vans with crossover fuel flow problems. Only some vehicles were part of the recall. My 1989 E150 was, my mom's 1989 E150 wasn't. Ford was supposed to have fixed the problems with crossover fuel flow. I called Ford before I replaced my mom's change-over valve on her 1989. I'm not sure if Ford has any newer recalls but if you call your local Ford dealer, ask for service and tell them you want to check a vehicle VIN# to see if any open recalls exist on your truck. If there is one for your cross fuel flow problem they fix it for nothing. If not, locate the valve and swap it out. It took me 20 to 30 minutes on the van.
I have been unable to locate the valve on my 1991 F150 however, it isn't mounted in the same place my 1988 F150 and her 1989 E150 are. I can't tell you where yours will be located.
Ford has had at least three designs. Generation 1 had the fuel selector valve. For the pickup trucks it was through about mid 1989. There was a recall on those.
Generation 2 got rid of the selector valve, using instead a "fuel delivery module" in each tank. The FDM has a high-pressure pump, a check valve and a shuttle valve. The check valve prevents backflow from the pressure side, the shuttle valve ensures that the fuel return line is only connected to the tank with the pump operating. In mid 1993 there was a different recall on generation 2. The fix then was to change out the regulator and add a redundant, external check valve in the pressure line coming from each pump.
Generation 3 would apply to your 1995 era truck. I believe this is the same as Generation 2, but not subject to the 1993 recall. Presumably it has an improved design Fuel Delivery module. It might have extra external check valves, as in the Gen 2 recall, though I doubt it.
If the check valve in the non-active tank leaks, there will be quite a bit of fuel transfer, because there is 40PSI worth of "head" on the pressure line. If the shuttle valve on the non-active tank leaks or sticks open, there can also be fuel transfer, though not as bad as with a leaking check valve, because there is less head.
If the shuttle valve in the ACTIVE tank sticks closed, it will create considerable back-pressure on the whole system. This may force fuel past the check valve or shuttle valve in the inactive tank. You should be able to tell that this is happening by the excessive fuel pressure evident at the fuel rail.
Chances are the problem lies in the rear tank. You have to replace the complete fuel delivery module. These are available at places other than Ford. It might be possible to add the redundant check valve, ala the 1993 recall, for less money. It is possible there is a recall on the later models, or that Ford would help you out, since it is a safety concern. I don't know, because I have a 1991.
I have a 95 F350, 460ci with the same problem you described on this forum. My back tank pumps into the front tank. I discussed this over a two-week period with my local Ford dealership and allegedly with the regional rep but their attitude was "Get out of my face." A complaint at National Highway Transportation Safety Agency (nhtsa-dot-gov)is next. If they don't want to fix my truck, they can fix all of them. BTW, the NHTSA number for the 90-93 recall for the same problem is 93V125000. And, one check valve from the 90-93 recali is $250. Yeah, right.
May I ask what you eventually did to solve your problem? I can install a new pump but I'm not sure where the check valve actually is. Nor can my local Checker slash NAPA guys. The FDM is $100 more expensive than just the pump ($150 @ checker) and my attitude is telling me their might be a Toyota truck in my future right about now.
I Haven't done anything yet. Too cold up here in Northeast. I was considering calling NHTSA and playing dumb by saying the tank was overflowing and causing a fire hazard. Maybe they could issue a recall. THe earlier trucks with a different system had a similar problem and they were recalled. This system is harder to fix, though. Only way is to pull the tank and replace the FDM (or as some have suggested, lift the bed to get to the FDM). It's a unit, so you can't just replace a check valve. I think Ford has abandoned the dual tank philosophy because they know it has caused problems.
This is caused most likely by the Fuel Pressure Regulator. I have a '92 Flareside 302 w/ dual tanks and had this happen about 5 years ago except the fuel was flowing out the front tank fill spout. Ford had a recall on this and still should check with Ford or your local dealer.
was in a hurry on the last post so I forgot to mention that the dealer also told me there was no recall when this happened and charged me big bucks to fix the problem. 2 months later I got a letter from ford stating that this was a recall and they refunded most of my money.
Yes, call your local Ford dealer. I usually ask for the service department and specifically tell them I want to "check a VIN number to see if there are any open recalls on a vehicle". They have a system they access to check, again by VIN number. I have searched many forums on this website looking for references to where the check valve on my 1991 F150 is and found mine is unlike the 1988 I have which is on the frame between the tanks. I found it is incorporated into the fuel pump assembly somehow. My front tank doesn't even work right now. I haven't gotten to replace the switch yet. Once I get that done I will also see if my truck has a cross fuel flow problem as well. I've already dealt with my mom's 1989 E150 van's same problem. It, like my 1988, has the external valve.
I have been reading about the fuel problem you all are having. My son is in the same boat with his 95 F150. I am a loyal Ford guy with a 2006 Freestyle, a 2004 F150, a 1997 Lincoln Mark VIII, the 1995 F150, a 1973 Mustang Conv show car. I also have projects I am workin of of a 64 Comet, a 68 Cougar, a 53 and a 55 Ford Truck. I mention all this to say that I am as loyal as it gets, but it really ticks me off to see Ford or anyone for that matter turn their backs on us loyal customers. I think we should all get together and file a class action suit against Ford to force them into a recall. Let's get together and solve the problem. We may be the only hope Ford has of surviving as they are stupid enough to stick it to the very people that keep them alive.
Yes, a recall that forces them to pay all kinds of money they don't have to fix a 14 year old vehicle will certainly help them survive. It's already been recalled once before and now time has expired. Buy a fuel pump and keep on trucking. Oh, if you buy the pump from the dealer, that will go much farther helping Ford survive than a lawsuit.
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