This is a 460 w/Holley 4B carb. Duel Tanks. Fuel lines go from carb directly back to tank selector on rail behind driver side and then to each tank. I see no mechanical fuel pump. Checked Inertia Switch-power is working. Vehicle has been sitting but i have been starting every week. I am not hearing any energizing of pumps when the ignition is on or cranking. I cannot find any fuse box under hood, only under dash. All fuses under dash check out good. Replaced both Fuel Relays[Power up (EEC) and Fuel Relay(green) on driver side fender under hood. Tank selector switch under dash panel indicates fuel in both tanks(it moves when the toggle switch is changed from tank #1 to #2).There is one small 3Amp fuse at the bottom right of the fuse panel that does not have any power even with a new fuse, key on or off. I'm not sure what that fuse is for. I checked all the tank selector wires where they plug into selector, with the ignition key on, and no power is indicated with the testlight on any of the contacts that plug into the selector. No power to tank selector wires during cranking either. Is there a 5 pin Fuel Tank Select Relay ? If so, where is it located ? Both tanks have fuel. Any suggestions ? <!-- google_ad_section_end --><!-- / message -->

 

For testing the system you need to jumper out the oil pressure switch at the back top center of the engine. Then turn on the key and you can check every thing without cranking the engine.
You need to do all of the power testing with a test light and not a meter.

Here is a wiring diagram:


/

 

Thanks Bill. Can you give me a walk-thru on the testing? How do I "jumper out" the oil pressure switch ? Give me some details on checking out everything with the testlight. I need some step by step help as the electrical troubleshooting is a bit of a mystery to me.
Order of testing would be helpful too.

 

You have no EEC relay. Only the 5 pin Fuel Tank Select Relay and the Fuel pump cut-off relay.

To jump the oil pressure switch do it as in the photo below.
First you need to locate all of the items in the diagram above.
Most are in the photos below.

Maybe it would be better if you emailed me your email address and better yet if you would email me your phone number and when to call you.
My email address is at the bottom of this post.

Oil pressure switch jumped:


Tank selector valve/relay:


Fuel system diagram:


The relays:


/

 

Well, thought I had posted a reply .. but nothing here.

So, thanks for the info again!

Now, how is all of these effected with an auxiliary battery ... (and a generator )?

Jeff

 

The auxiliary battery and the generator are for use with the coach and not the chassis.
The engine charging system does charge the coach battery but not the other way around.
Some do have an jump switch that you can push if the chassis battery is down to get your engine started.
The auxiliary battery and the generator have nothing to do with the fuel system.

 

Hi Bill,
Could you send me the pics that you sent of the relays and wiring diagrams and how to jump the relays and switches.

 

The images have been restored.
Do a reload.

 

I've run into an issue where I have no resistance when I turn the ignition key. I have learned it is most likely the lock bolt spring, do you know where I can get one or should I just put a start button in.

 

Ignition switch shown as 11572 in pic, bezel shown as 11584 .. Where is this lock spring bolt?

 

Sorry it took so long to get back to you, but I went to ford dealership and found out ford no longer makes the spring anymore.

 

Check the column for the rod going from the cylinder to the actual ignition switch that has the wires going into it. You should be able to purchase it at any auto parts store. Your key lock will have little resistance when it breaks. https://www.rockauto.com/en/moreinfo...EGNXVdv49Jx8H8

 

I can't find a replacement for the oil pressure switch.
Who made it in which year.
The ford dealer was clueless. Parts stores dont know what to look at. And Google isnt helping.

 

Okay great---another newbie who doesn't list WHAT they're working on and tacks onto an unrelated thread NOT of the issue.

They're all over RockAuto.

 

How about you stick to HELPING solve the problem instead of ASSuming you know everything.

I know what this thread is about. Been watching it since early last year. My problem is similar with the same set up.
So, NOW here is the answer.
Ford did NOT make an oil pressure switch for a dual tank system. Oil Pressure Switch is NOT the oil pressure sending unit.
Thanks for nothing JWA.