I have a 86 f250 xlt lariat with a carbed 460 with only 64k miles. When I got the truck it had been sitting for 27yrs so i got it a standard tune up and it ran fine for about a week and now it wont stay running at all. It gets enough fuel to run for about 30 secs but soon as the fuel sent to the carb from the pump when i first turn the key burns up, it dies. Its like the fuel pumps are pumping enough fuel to start it but soon as it starts and the pump switches power sources (i dont know what powers it when its turning over or what it switches to once it starts running, all i know is that it gets power when starting then switches once its running to a different source) it dies. When I 1st looked at the engine when this happend I saw that there was no vapor seperator (inline filter) and the return fuel line was not hooked up. Also there was no fuel filter in the carb, so i put a new filter in the carb as well as the vapor seperator whitch also hooked up the return line but still nothing. Im not super mechanic so i have a hard time trying to understand the schematics on here. Can anyone help me? On top of all that i was trying to start the truck and I think I tried to many times cause now it won't turnover at all. It seems like the battery is dead but I checked it and its good. I also tried jumping it and that did'nt work. When I turn the key now it sounds like the battery is being drained. Also when I turn the key all the lights dim to almost off and all this happens with the battery soon as i turn the key. What could this be now? I don't know what to do now.
<!-- / message -->

 

First, I really do want to help. But, I'm finding it very, very hard to wade through your post since you don't capitalize the first word of the sentence and many of your sentences are extremely long. There's been a discussion of similar posts on here and many of the guys won't bother trying to understand them and just move on to help someone else.

So, I can't say I have my head wrapped around all you said. But, I do have some questions and suggestions. Did you drain out all the old gas and replace it with fresh? Hopefully so, and I also hope you actually removed the tank and flushed it out.

I say that because I bought a truck that sat for 2 years and its fuel had turned to turpentine. We removed the tank and poured the stuff out, poured in 2 gallons of fresh gas and put a chain in with it, and sloshed gas and chain for quite a while. Dumped that and did all of that over again 3 more times. The inside of the tank looked good so we put it back on.

After filling the tank up and starting the engine the accelerator nozzles plugged very quickly and we removed the metal fuel filter that screws into the carb and took it apart. In fact, we took two different brands of those filters apart. As it turns out, those things are good for stopping gnats, but little else. So, we installed two see-thru plastic filters, one ahead of the mechanical pump and one between the pump and the carb. And even then the nozzles plugged one more time.

So, if you haven't dropped the tank and cleaned it out I would highly recommend doing so. I can't even imagine how bad it would be after sitting for 27 years. And, will you have it out or the connector off the pump I would put either a light or a meter on the connection to the pump and have someone turn the key. If you have power in both Start as well as Run then consider replacing the pump. If only in Start then find out where the power stops, although that will take getting a manual or having someone who has one post a copy of the wiring diagram.

And, once you have power to the pump and a clean tank then install a see-thru filter that uses a pleated filtering material. That way you can watch to see if it is needing to be replaced.

 

Sorry about the crapy post its my first post. Thank you for the advice I will try that and see if that works and post my results. Also any idea what the issue with not having enough power to even start it now?

 

Thank you, Nate, for writing better!

White space between paragraphs helps tremendously, too.

About the power thing... turn on the headlights and turn the key to START, report what happens to the headlights (they dim a LOT and almost go off, they dim only some but not a whole bunch).

I'm thinking bad electrical connections at the battery/solenoid area but, if the lights go WAY dim when the starter motor is trying to turn, this could be a failing starter motor (or the wiring leading to it), too.

 

Hey! That's a lot easier to read. That helps me to help you.

I did forget the starting. You said it now won't turn over at all and acts like the battery is bad. But, apparently the lights come on fairly well but go dim when you hit Start. How did you check it to say it is good? A battery can fail internally such that it gives the proper voltage with no load on it but the voltage drops dramatically when a load is put on. The best way to test that is to take it somewhere like a parts store that tests batteries for free.

If the battery tests good then you either have a connection problem or a bad starter. The parts store can probably also test the starter, but it is a bit harder to take out to say the least. So, I'd check the battery and, if good, try to start the truck. Then work on connections and then starter.

For connections, you should pull/clean/reinstall the following, and should also check the condition of each cable in the process:

• The positive cable connection to the battery
• The positive cable connection to the solenoid
• The starter cable at the solenoid
• The starter cable at the starter
• The negative cable at the battery
• The negative cable at the frame
• The negative cable at the block

And, when I say "clean" I mean they should be wire brushed and down to bare metal - both sides of the connection as well as the bolts. And, I like to use anti-seize compound to ensure the connection stays good, but that's not required.


If the battery is good and the connections and cables are good then it is the starter - assuming the solenoid is closing, and it is if the lights go dim.

 

I use dielectric grease for electrical connections, never heard of using anti-seize there.....?

 

I wouldn't use anti-seize on delicate things like transistors. And, you can't use it on connectors where there are multiple circuits unless you are very careful. It would be easy to get it across two circuits and it could short them out as it has metal particles in it.

But, for battery connections, grounds, etc it works well. It certainly won't wash off and since it conducts it actually helps make the connection.

 

If you get enough fuel to 'start' and not to 'run' either the inertia switch needs to be reset, the oil pressure switch is not functioning or the fuel pump relay is bad.
While cranking, the fuel pump is powered directly by the ignition switch.

To me it sounds like all your cranking has melted the starter windings and it is drawing too much current.
You did say the battery was tested...

 

Yea I took the battery to a shop and they tested it and said it was fine. The headlights dim to the point where there almost off when I turn the key. This battery problem started because I cranked it over for to long. I can't figure out how to jump or even check my oil pressure switch. I know where its at but it doesn't look like the other ones ive seen. I will try to post pictures of my problem areas.

 

I apologize in advance for the super long post with all the pics. I just thought it would be best if anyone with the ablity to help me was seeing what Im seeing, not sure if this will help but cant hurt to try so...

This is my oil pressure switch. I do not know how to jump this cause the grey piece that the 2 red wires are coming out of is like a plastic cap or somthing i cant seem to just pull it off.



This is my battery and starter. Im not sure how to test the starter to see if it is working properly.



This is my fuel pump relay. Not quite sure how to test this either.



This is my fuel tank selector switch. Im not sure what to do at all here. The only thing I've done here is bleed the lines looking for junk in the lines.



This is my fuse box, it had no cover on it so i dont know what fuse does what. I herd somewhere that there is a fuse that could be the problem but as far as I could tell none of them here are blown.



This is my vapor seperator. I had to install this because when i got the truck the main line went straight to the carb and the return line was not hooked up. Also there was no filter in the carb but I did install one.



Finally this is my carb. On the back of the carb there is a round piece that sticks straight out and in other pics Ive seen a hose hooked up there but there is not one on mine. Im not sure if Im even supposed to, just thought i would bring that up.

 

I'm sorry Nate, but your pictures don't seem to be coming through. Can you edit your post to be sure you don't have double http:// in front of the IMG code?

 

Also if anyone could give me a step by step for removing my gas tanks without messing something up that would be great. Also I have tools but if someone could give me a list of any special tools i should need to fix or work on any of the problems I have that would be great as well. I have all the basics like sockets (i dont have deep sockets just the standard), wrenchs, vicegrips, ect.....

Thank you so much to anyone and everyone who is able to help me or give me advice, I really appreciate it. I have been trying to do this alone with no one to help me and ive had learn everything from trial and error. I started off with no knowledge of trucks at all and this site has helped me learn so much, thank you. I have a 4yr old who relies on my child support for everything and as long as my truck is giant paper weight, I cant work and earn my paycheck for him. So again THANK YOU EVERYONE FOR THE HUGE AMMOUNT OF SUPPORT AND HELP, THANK YOU.

 

there is not a double http. it just says img before and after. is that normal?

 

Heh, Nate....

You have to put your images up onto a hosting site, something like photobucket or imageshack or some such, then use the URLs to the images on their server.

You're trying to post pictures that are attachments in your google mailbox, we can't get into your mail to see them.

This might help ya:

User Gallery & Picture Display Help - Ford Truck Enthusiasts Forums

 

Well, you're certainly in the right place if you're looking for expertise on these things. The knowledge contained by the people on FTE amazes me at times.

As for your gas tanks, this is pretty hard to mess up as it's all pretty basic.

I think what I did is disconnect the rubber portion of the filler tube from the external filler neck, then drop the tank(s) at least partially so the rubber part can be disconnected from the tank.

There is a plastic vent tube inside the filler tube, be sure that gets reassembled correctly and stays in place to avoid hour-long waits at the gas pumps to fill up the tanks.

See if either of these threads answer any of your questions:

https://www.ford-trucks.com/forums/1113750-86-f350-rack-body-fuel-filler-issue.html
https://www.ford-trucks.com/forums/1...bed-302-a.html

As for tools, you're gonna find that many of the body fasteners and a small portion of stuff under the hood (basically, everything except most of the engine) uses metric-sized nuts & bolts.

There may be some 10 mm nuts/bolts involved with the gas tanks, I really don't remember for certain but 10 mm doesn't have a SAE equivalent - it's between 3/8 and 7/16 as I recall.

You'll want deep-well metric sockets for the gas tanks, at least for the side tank.

You should also get a multimeter (aka DVOM) and maybe a test light. Sometimes an analog meter (with a needle) is better than the digital variant, it'll be up to you and what your preferences are.

Harbor Freight & Walmart sell digital meters for $5-$10 as I recall.