That appears to be a sealed style locking gas cap. I really appreciate locking gas caps as I just had 24 gallons of diesel siphoned out if my F two fiddy at the Denver airport. I don't think they make a locking vented gas cap but I could be wrong.

I would vent the tank using the later style (76/77) rectangular charcoal canister mounted to passenger side firewall. You just run a hose from the tank vent up to the charcoal canister with an inline check valve to keep it from leaking fuel in case off off camber or roll over condition.

This way you would be filtering the vapors rather than just venting them to atmosphere.

This system doesn't use the evaporation tank which is designed to return condensed vapor (liquid fuel) back to the tank (not the engine).

The reason you had fuel leaking out the filler neck is that the tank was full enough such that it couldn't accomodate the fuel which had expanded due to ambient temperature (or you were parked at an angle?).

The PO of my bronco drilled the small hole just at the body edge of my filler neck. The canister is the better way.

Even with the evap canister, charcoal vent etc... I had my aux tank puke out from the cap on the New Years run a couple of years ago. Filled tank up too much, once I loosened the cap all was good

Closing this chapter (HOPEFULLY! ). Here is what I did since having this issue:

1. Rerouted driver side dual exhaust into the passenger side exhaust. There are now no exhaust lines anywhere near the fuel lines. It is much quieter, which in my 20's, I probably would have been extremenly dissapointed, but I kind of like it now.
2. Bought a locking vented gas cap. I know a lot of people weighed in on the idea of converting to the later style evap canister, but I just didn't have the patience to do yet another unforeseen upgrade. Maybe down the road-- also, a vented gas cap was a much cheaper solution.
3. Installed an in-line liquid filled fuel pressure guage. I did this first before removing the mechanical pump to see if I was getting any pressure and low and behold, I had no pressure at all registering. I thought the guage was damaged because I thought for sure I would see some sort of pressure. I called JEGS and they told me they were sending a new one at no charge and to just throw that one out. I will say, JEGS has had excellent customer service everytime I buy something from them.
Fuel pressure.JPG

4. Removed the mechanical pump and installed the Carter P4070 as well as a "better" in-line fuel filter. Fired the Bronco up and all is functioning properly-- EVEN the fuel pressure guage. It was reading 4psi right after I fired it up... guessing after it warms up a bit, that number could climb up to 5? Clearly, the mechanical pump was toast.
Carter Pump.JPG


So I am hoping that a combination of exhaust running too close to the line would heat the fuel up way too much, thus causing evaporate in the tank to cause a vacuum type effect because of it not having any venting capabilites, ultimately causing the vapor lock becuase of a bad mechanical pump. Sounds good to me... now I just need to test and hope I don't get stranded somewhere again!

Thanks for everyone's input the last week or so...

Nice, Ill be keeping my fingers crossed. I know how frustrating a problem like that can be.

Sent from my C771 using Tapatalk 2

Sweet, hope it fixes it for ya.

So I had no issues starting the Bronco since all of my repairs have been done the last couple of days. Took it to run a few errands yesterday and things seemed to be fine. I remembered that when we had installed the Power Steering a few months ago, we had to remove the coil from its location to bolt in the power steering cooler. I had read on CB.com that someone was having some issues with losing power at higher temps and they traced it back to their coil. My coil had actually just sitting pinned in a location fairly close to the block hence probably heating it up. The plug wire running from the dizzy to the coil is too short to route it someplace at the moment so my plan was to get a longer wire and bolt it to the inner fender away from any heat source. However, I went to start it this evening to run and grab dinner and now it won't start. The ONLY thing that I did since it ran yesterday was pick up the coil to take a look at it--- maybe turned it on its side and was looking at the mounting bracket.

When I attempt to start it, it sounds like it has plenty of power, it turns over like it wants to start and I can definitely hear the fuel pump and I have fuel pressure (and I can smell fuel.) My only thought is that this coil is acting up. How can I test the coil? I do have a mutlimeter. Does this sound like it would/could be a bad coil?

Make sure you see 12V to the coil with the key on. If not troubleshoot the ignition wire to the switch.

Should have 1-2 ohms on primary side of coil (between the 2 small terminals, wires disconnected). 7-9K ohms on the secondary side (either small terminal and the high tension terminal).

I don't know, so I am throwing this out there - doesn't a coil need grounded to the body? You mentioned you moved it. Is it just hanging there?

Your secondary should be something like 5-10,000 ohms. I'd replace it. A failing coil getting hot could account for your issues.

Gotcha, that makes more sense. The wiring whisperer is the one to be talking to about this for sure! Could be drained battery not spinning the engine fast enough as well, especially if it's older.

Here is where I lay dead and beaten:

Per Phil's suggestion, I took the plug wire end on the dizzy coming from the coil off and tried to hold it close to a ground (not sure if I am doing it right since there is a rubber boot on it). I did not see any sort of spark.

I used a spark plug light/tester (http://www.oreillyauto.com/site/c/detai ... t+%26+tune) and followed the directions of plugging the black end into the spark plug-- and then sticking the silver probe into the spark plug wire. I tested the spark plug at the front of the passenger side. NO light whatsoever popped on.

I checked the voltage at the battery and was getting 12.5V and then around 8-9v when turning ignition.

....SO, now what?

These things happen, at least you haven't made any "bad" changes, or replaced any good parts. Everything you've done will only help it be reliable down the road. The fuel/exhaust routing, and fuel pump were good reliability upgrades. The old fuel pump was waiting to bite you sooner than later.

Wish I could help with the spark problem, I had a MSD set up from day one, until I went to Ford EFI a couple years ago. So I know squat about the stock ignition. I took a couple weeks to figure my MSD failure out.

Good luck

I have almost this exact set-up. Looks like a Ford upgrade a while back. Duraspark ignition module with Ford distributor and coil.

Did you mean that the voltage drops to 8-9 while cranking or just key on, either way that's an issue, it shouldn't drop below 9.6-10v when cranking, if it is that would most likely indicate a weak battery, but obviously no spark is your primary issue, and if just keying on that would be a serious draw, but even with 7v to the coil there should be some spark, unless there is an issue with the module, pickup coil, or wiring, currently the coil sounds like its ok, if I had some more time to look at diagrams and think on it I'd give more input, I haven't dealt with duraspark much, so without doing some reading I wouldn't be to much help, when keyed on, not cranking did you say the voltage to the coil was 7v, if so it's possibly a bad connection, or left over resistor wire, or ballast resistor, ill let the duraspark guru take it from there

Sorry had to edit the post above, meant to type more, accidentally hit reply. Well if you just want to make sure you have battery voltage at the coil with the key on not cranking, if that checks good I would be talking to Phil about either, pickup coil, duraspark module, or wiring to the module from the body, and wiring between the pickup coil, module and ign. coil, in the meantime while your waiting on Phil's response check for broken wires, backed out pins, chafed wires, poor connections at the module or distributor and anything in between

If you want to install the mile marker ign, I do have the paper work for it, I will locate the file and give it to you

Here are some troubleshooting procedures. Duraspark is a very good system. duraspark troubleshooting[1].pdf

We are running duraspark in Willem's rig and it has been trouble free. If you end up needing a spare module let me know, I think I have one on the shelf.

Thanks Keith. Whenever you track it down let me know. I've got some stuff for you as well. Thanks for the PDF Phil. Kirk, I'll let you know if I determine its the module. May borrow yours until I rewire and most likely add the Mile Marker.