One Fuel Tank Pegs Gauge

crash-harris

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Ok guys, I got my new tank selector switch plugged into the dash about an hour ago and the stock FSV now switches!

The bad, as soon as I switched to the front tank, the fuel level gauge pegged. As some of you know, I replaced the 2 wire harness on the front tank due to it being burnt all the way to the frame rail. I triple checked my wiring and pulled factory wiring out of the harness and nothing is amiss. Does it sound like the board for the float in my front tank is trash and grounding the single wire? I haven't even tried to pull it out and look at it since the lock ring looks to be rust welded to the tank. I'll most likely have to replace the tank if I pull it out.

This and retiming the IP are my only mechanical issues now! UPS is delivering yet another driver's fender Wednesday and I'm trying to get the reusable panels sanded and primed so she'll be on the road after next week!
 

The Warden

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On a brick-nose or OBS truck, a pegged full fuel level gauge indicates a dead sending unit (a slant-nose will peg empty). You might get lucky and have a connection issue, but I would be prepared to replace the sending unit...and, from what you said, possibly the tank as well. You might try soaking the lock ring in Aero-Kroil before trying to turn it.
 

crash-harris

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I just tried toying with the lock ring. The tabs are just decoration at this point. Touch one and it disintegrates.

I failed to mention, there is no change if I unplug the harness from the sender, so maybe it's just not making contact?
 

typ4

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When open the gauge pegs on a brick. I have dead spots in my front tank rheostat and it runs out when at 1/2 tank. bounces all over as it goes from full to out on a trip.
I have the part number here somewhere. Ill post it when found.

I know Motorcraft PS 22 is for the brick Bronco tank.

PS 19-20 and 21 also fit but have no description on amazon. so all will fit but may take some float arm mods, I would buy the longest, easier to cut than add.
 
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crash-harris

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When open the gauge pegs on a brick. I have dead spots in my front tank rheostat and it runs out when at 1/2 tank. bounces all over as it goes from full to out on a trip.
I have the part number here somewhere. Ill post it when found.

I know Motorcraft PS 22 is for the brick Bronco tank.

PS 19-20 and 21 also fit but have no description on amazon. so all will fit but may take some float arm mods, I would buy the longest, easier to cut than add.

Thanks! I'll cross reference it with something hopefully cheaper. I'm reading well above $100 on ebay for all 3 part numbers. I can always just pull the float arm off the one in the tank and snap it on a new sender.

To that affect, what's the difference, or is there any at all, between the gas and diesel fuel level senders?
 

typ4

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No difference. or buy a gas sender which is less than 100 and rob the board off it. I bought motorcraft ones 8 or so years ago for 18.00 each. I should have bought them all.
 

crash-harris

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OEM Replacement switch, about $37 from quickparts via ebay. I have a feeling that the in tank level sender is why the factory sender harness was fried. I'll probably leave it for now and try to get into it after the wedding/honey moon/vacation, so like July or later LOL

Gotta get to hauling and riding All State for this property damage claim.
 

typ4

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There is not enough current in that circuit to fry wires, but is someone was in there with test leads, possible.
 

crash-harris

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Ok, now I'm not so convinced that the sender is bad. Played around with it a little after painting and it ohms out at 16.6 ohm. I couldn't get continuity between the tank and the bed/frame/exhaust (but batteries are out right now, yet it should still ground). I know there is fuel in it, 5 gallons or more. And the other odd thing is that the fuel gauge pegs regardless of the fact that the harness is plugged in on the tank or not?

If the harness isn't connected to anything, there would be no current to flow from hot to ground, so could it be something in the FSV, like a loose/broken contact always making a connection? Like I said, I traced all the wiring for it and nothing else is burnt, frayed, outside the split loom touching anything and overall hunky dory.

Thoughts on that?
 

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