I was having a problem with switching from my front fuel tank to my rear fuel tank. At first, the truck would only run when switched to the front tank. Now it will not run off of either tank. I am getting zero fuel pressure off the rear tank and very little pressure off the front. I am also having a problem with my ignition system (little to no spark). What does the fuel selector valve on the frame rail have in common with the ignition system? Could this be my problem? The reason I ask is that the replacement valve at my local parts house is called an "ignition fuel selector valve". The truck is a 1985 F-250 4X4 with a 460 and currently has a breaker point type distributor in it.

Thanks,

Zeus

 

I am about 99% sure the selector valve isn't tied into your ignition at all, I think that is a separate problem in itself. How are you checking your pressure? there are not fuel pumps in the tank so they won't just push fuel magically. Will your truck run if you dump a little gas in the carb? or on ether?

 

In 85, there are pumps in the tank, the system uses two low pressure in tank pumps. The selector is operated via the pressure from these pumps, it is basically a shuttle valve that slides when pressure is applied to either side. There is a filter in the base of this "valve" that will block the system if clogged. Last time I got one, i wanna say it was 7 bucks from napa. That may be an issue for the fuel pressure. another issue may be not enough voltage at the pumps, it should have full system voltage, and a clean ground. The usual aftermarket selector is electically operated and not compatible without modification. Now this all relies on the system being as originally equipped an unmolested. From the sound of things, this may not be the case.

If you have a points distributor in there... first question is WHY?? Next, you need to check voltage at the coil, check the resistance in your wires, check the cap for fouling/carbon tracking etc, also the point gap and point condition (burned etc).

Just a few places to start...

 

My mistake my 87 EFI truck didn't have any pumps in the tanks nor did my 79 w/ two tanks.....guess I was assuming :P

 

D5TZ-9189-B .. Fuel Tank Selector Valve

6 ports / Marked: E57B-9F271-BA

Fits many different models and engine sizes 1985/91.

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This is on my son's truck that we just purchased not too long ago. I did not notice that the previous owner had swapped in the old point distributor until we tried to do a tune up. I'm guessing that he fried to old system and had this on hand. The old connecter where the ignition box plugged into was melted beyond use and bypassed. As soon as I can make the 100 mile trip to the junkyard, I plan on putting it all back the way it should be. I just need to locate a wiring harness and other parts to replace it.

When I spray starting fluid in the carb, it will not start. Sometimes it seems like it wants to start but just cant quite make it. I put a timing light on the spark plug wires to see if it would light up but no luck there either. I changed the points, condenser, cap and rotor and coil. Still no spark.

As for checking fuel pressure, i do not have a fuel pressure gauge. I disconnected the fuel line and cranked the motor. At first no fuel would pump out of the line. Then after cranking for a while, the clear in-line filter would slowly fill up and then seep out of the fuel line. It seems like it should pump quite a bit more that what it's doing. Maybe it has a safety cut off that senses the open line?

Is there a computer or relay on this truck anywhere that could be causing my problems?

 

get an hei style dist for it. with your wiring woes it seems like it would be your best bet. With those all you need to do is give it juice, they are a self sustained unit. no ext coil or box or anything. they go on ebay for around $100. worth it to me, especially since your wiring is fried.

 

Did you try putting the timing light pickup on the wire from the coil to the distributor? Do you have 12V to the coil w/ the key in run?

If it's anything like my '87 it should have a mechanical pump on the side of the timing case. Where is the inline filter? The mechanical pump should work anytime the motor is cranking. Carbs only need 5psi or so to fill the floatbowl.

Not that I'm aware of, are you sure the ignition switch is working properly? Do you have a schematic?

I don't see how your '85 should be much different than my early '87

 

Jim, I'll check the voltage to the coil with a meter tonight when I get home and try the timing light pickup on the coil wire. I'm not sure if my son checked that or not.

As for the mechanical pump, this truck does not have one. It has a cover plate blocking the area where it should be. It has two electric pumps (one in each tank). When I turn on the key, I can hear them loading up. That's why I was thinking maybe fuel is not making it past the tank selector valve. The inline filter is located just before the carb above the intake manifold.

I do not have a schematic. I did notice that the solenoid looked like it had been pretty hot at one time. The insulation on the battery cable was melted and the insulation on the ignition wire was partially melted where they connect to the solenoid.

scottie2hottie,

Which part # of HEI distributor would I need to be compatable with the 460? I'm not familiar with HEI distributors other than a GM HEI. Is this what your refering to?

Thanks

 

Well, at least that would tell you whether the switch, coil or distributor was at fault.
It sounds to me like this truck did not come from the factory w/ a 460. Try to use the VIN decoder at the top of the page under 'articles/specs' to find out what it DID come with. Then you can find a schematic that resembles what harness is left in the truck. (you might also do some research into what your 460 came out of)

Good luck sorting this out Zeus.

 

Yes it is GM HEI style distributor built for the ford 460. Uses the theory of HEI and one-wire hook-up for a ford. Check out the following ebay auction:

http://cgi.ebay.com/ebaymotors/Brand...spagenameZWDVW

 

Locate the selector switch, should be on the drivers side frame close to under the drivers seat. Remove the line from either the main tank or aux tank before it enters the selector valve and then check pressure and volume at that point. The switch is electrical and is selected by the switch on the dash. It switches tanks and tank pumps. If you need to replace the valve use a ford unit instead of an after market valve, fuel lines do not mate up on the after market units.

Only thing common between the distributer and selector switch is battery voltage.

 

I like the idea of this HEI distributor. It really makes things look eazy...the price is right too. Can anyone let me know if they have actually used this and how it worked out?

http://cgi.ebay.com/ebaymotors/Bran...sspagenameZWDVW

 

Sorry I was not more clear on this.

I had asked if there was 12V to the coil w/ the key switch in 'run'
Looking @ the schematic for a '84-'86 FI truck (assuming this was a FI truck to begin w/) it seems to me that the 'start' position is one pin, and that the tank selector and ignition coil are on another ('run').
IF the switch or the red/light green wire were bad I belive it could get power in 'start' and loose power when the switch returned to 'run'.
Obviously the harness has been hacked, but I just don't know how bad.

 

I checked to voltage to the coil with the key switch in the run position. Voltage was 6.95 to 7.0 volts testing at the coil. I'm not sure yet where power to the coil is coming from yet. It was too dark for me to see clearly when I got home.

I talked to my neighbor about the coil voltage and he said that if I was getting 7 volts or higher at the coil then I either had a bad ground or a bad coil. He said if it was operating correctly, that the voltage should be lower. He then said that I could run a ground wire from the neg side of the coil to a good known ground and re test the voltage. If it dropped to around 4-5 volts with the key on, then my problem was a bad ground in the ignition system somewhere and would need to be located and fixed. If the voltage did not drop then my coil was most likely bad and needed to be tested. Does this sound like he knows what he's talking about?

There is not much of the harness (under hood) from the original electronic ignition is remaining. The two of the three wires had been cut behind the plug that had connected to the ignition box that was mounted on the inside of the fenderwell. Also, the plug itself had been melted together to the point that nothing would be able to ever be plugged in to it again.

As for inside the truck, I have not checked any of the wiring or ignition switch yet. I did however take a quick look under the dash and found a nightmare of wires dangling where it looked like the previous owner had a stereo, aftermarket gauges, and off road light switches hooked up. I will try to take a closer look at it this weekend.

One more odd thing...under the hood the truck is set up for cruise control. However, inside the truck there are no controls/switches to set or otherwise operate the cruise control. It does have an aftermarket steering wheel. Were the cruise control switches located in the original steering wheel?.....if not, then that means that someone changed the steering column too. Hmmmm...........the plot thickens I guess.

The truck is not a Fuel Injected model. It has a new 750 cfm Edelbrock AFB carb #1411 on a performer manifold. I replaced the old holley 750 that was on the same manifold thinking the carb might be contributing to the problem and since I really dont like holleys to begin with. It appears that all emissions equipment have been removed or bypassed.

I'll check it out a little more tonight when I get home.

Thanks for all the input.