Hey guys, I read the great thread that was on here from a couple years ago, and have printed out the fuel system diagram. My issue is a bit different than that individuals, so was going to post asking about where maybe to start looking for my problem.

This coach has the 460 in it with the C6 transmission, front and rear tanks. (we just bought it used two weeks ago, I changed oil, flushed transmission, new batteries and made new cables. After they adjusted the carb it managed to pass smog, I'm in CA, yesterday).

Issue 1, starting it from the front tank, if it's been sitting a few days it doesn't want to start, and we end up pouring a bit of gas into the carb to get it to fire. after that it'll run fine after it warms up, and the next day even it'll start after a couple of tries.

Issue 2, the other day I put a few gallons in the 2nd/rear tank as well, and when I got to a stop light (right by my house) I switched to the rear tank. The fuel gauge does register the level of the other tank, but the engine ended up dying (I had turned the corner and it died out, so maybe 1 min after switching tanks).

My thinking on issue 1 is that it might be the choke not working right and maybe there is a slow leak so the bowls lose fuel after sitting a few days, and I plan to have a mechanic buddy go through it soon, is that likely?

Issue 2 I'm more of a loss at. any input appreciated guys.

Red

 

No ideas guys? did I not put enough information? I'm hoping to get some time to work on it this weekend.

Red

 

Issue 1:
Maybe a bad starter relay:

Issue 2:
Bad fuel pump in the rear tank or bad fuel selector valve or if you have the 83 stile with two relays selector relay also.

1986 one relay:


1983 two relays:


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An '84 460... wouldn't that have a mechanical fuel pump rather than the in tank electronic ones?

And since it does this after sitting a couple days, it may have an air leak somewhere in the lines causing it to loose prime, and since it "must" have a mechanical fuel pump, the engine has to crank to get the fuel back up.

 

Subford, your posts were the ones I read before and the reason I joined up, thanks for the reply. I think you're right on the first one, my uncle for some reason thought that it might be in the ignition, the "key tumbler" doesn't turn as you'd expect, seems "gummed up" since it's inexpensive I was going to change it out. I'll check this relay too.

I'm not sure which setup I am, one relay or two, I do know that the tank selector valve is marked e3ub-9b256-ca. I had already printed out your diagram of the 2 relay system from the other post, I'll print the other diagram too. I appreciate it.

John, it is definitely electric fuel pumps, the mechanical pump location on the engine is capped. (I looked there first, as I have a mechanical pump on the 429 in my 51 :-) )

I will check for air leaks too, they should have shown up when I had it smogged if it had them, which was one reason we waiting till after smog to start checking through everything. my uncle's 79 ford truck just failed smog because of a air leak in a hose in his fuel system. But you never know, I'm just hoping whatever thep roblems are they're easy to fix, I'm already at budget and this damn thing still has little things to get done.

Thanks guys, I'll post back.

Red

 

Do you leave it parked on a hill? Thinking the fuel may run back downhill if it's pointed nose-up.

If you only have few gallons in the back tank, it might take more than that to help prime the pump? I'd go with Subford's thought - bad fuel pump. Did you put in a new fuel filter?

 

It's the fuel pump!

All right, my buddy rebuilt the carb for me yesterday, the choke wasn't working on it. After it was installed it started and ran MUCH better, no pouring gas in the carburetor.

With that done we went to the fuel system. I have a relay mounted on drivers side fender area (this forum is awesome, my mechanic friend helping me out was surprised and wants me to show him how to look up this kinda stuff) it is working. On the frame there is a relay/switch that the fuel lines actually run through, it is working. And right at the tank (not up at the pump, but as close as I could get) there is power getting back there when it is switched. but the pump isn't running (ear against tank) so tomorrow I'm going to drop it down, confirm, and replace.

Thanks for all the help guys. This thing is pretty close to done now.

Red

 

Note that the gauge selector/valve has nothing to do with the running of the pumps in the tank. It just changes what tank the gauge reads from and changes the flow from a tank to the engine and back to the tank on the return.

The pumps in the tank are controlled by a relay and the selector switch on the dash or just the switch on the dash for the one relay set up.

The selector valve/switch on the frame:


The relays on the fender:


The fuel system:




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Shoot, typed reply then navigated away and lost it. My relay was not green, but was in the same spot and responded when the switche was operated. with a tester on the wire going to the pump I get power when the switch is on rear, and none when it is on front. I honestly was hoping it would be the relay or the switch, and I wouldn't have to drop the tank, but it looks like a straight forward deal, and I figure it doesn't have too much fuel in it so I can get it down with a jack and check things out.

I appreciate the help. My wife isn't too happy about all the time I'm spending on it, but I bet she'd be less happy if I was paying somebody else to do it.

Red

 

I hope you were on the wire going to the rear pump.

 

I got on the only wires I could find that came out of the bundle/loom on the frame rail and went up to the top of the tank, there are other ones that split off and look like they're going to the lights, these were the only ones going to the top of the tank, there were two, and up on top there is a ground going to the frame. I slit the cloth cover and there were two wires inside. when the tank was switched to the front I got nothing from either. when it was switched to rear I got power on one and blinking (tester that shows power with a light) on the other, my friend said that would be the signal to the gauge.

But when I drop it I'm going to put a jumper straight to the pump and see for sure before removing it. does it sound like I was on the right one?

Red

 

You did not say anything about wire colors.
The gauge wires are always Yellow with another color stripe OR another color wire with a Yellow stripe or hash on it.
Blinking does sound like the gauge wire though.
The pump wire should have near battery voltage on the selected tank wire if you jump the oil pressure switch and turn on the key.
The oil pressure switch is located at the rear of the engine top center. You would need to take the dog house off to get to it.

Oil Pressure Switch jumped:


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Hey Subford, I wanted to update you. I did look at the wires again by the way but can't remember, I want to say that one was orange, Id idn't see a yellow one, but they're pretty old and maybe my eyes weren't great under there.

I took the tank out, it had way more gas than I thought (must have had some in there already) so I drained it after I got it down. I didn't want to cut the filler and vent hoses at the top so fought them off, then found out they were cracked up top, I should have cut them to begin with.

The pump was for sure dead, and good I took it out anyways, the maxi pad looking filter disintegrated as I tried getting it out. (no, I'm not dropping the front one just to change it )

I got a new one in, and tested, but am waiting on the hoses now, I am slow so am going to have to finish it this coming weekend. I haven't taken as many pics as I should have but did get a few so will post them when done for anyone needed them for reference.

I really appreciate your help, I can see an end in sight with this thing!

Red