Fuel Tank Replaced, Hooray! Sending unit doesn't work, Booo.

[finkelstein]

So last fall, prior to a NY winter storage, I replaced the fuel tank in my '79 bay. This job proved to be a solid learning experience and I was successful in installing the new tank. Got it from BusDepot.

FYI, if you're running FI, you need to install your own return line. I braised in a nipple, then sealed it with a fuel grade silicone gasket making product. Held fuel over winter. I was a little worried, but so far so good. No runs, no drips, no errors.

Anyway, when I removed the old tank the sending unit worked adequately. When I reinstalled, it read empty. I stored it anyway as winter was setting in and I can deal with it in spring.

Thinking I must have reversed the wires in the reinstall I switched leads. Tank read full. Pegged way right full. Well, I put it away full, so it must be full.

So I drove it to work and back. Round trip 76 miles. Still pegged way right. This can't be correct.

Anyone have any advice on where to start? It reads full, so FSU must have power and ground, right?

Any help greatly appreciated. I know there are hundreds of sending unit threads here, but honestly, wading through them in futility is killing my aging eyes.

[busdaddy]

If it's pegged all the time the most likely suspect is reversed wires, unless you've managed to install the sender sideways and the float is hung up on the side of the tank. Another possibility is a pinched wire.

Luckily the firewall can be removed with the engine in place on a 79, sounds like it's time to go digging.
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[finkelstein]

[Wildthings]

If the wires were on correctly when it was reading empty then the sender could well be bad. You may have jarred the sender around hard enough moving it from one tank to the other for it to decide its time had come. If the sender is bad, you might consider rewinding it verses replacing it as the new units aren't known for their accuracy. Ni-chrome wire doesn't cost all that much and you can find instructions either here on TS or elsewhere on the web.

[SGKent]

RAtwell:

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[busdaddy]

[finkelstein]

[finkelstein]

Ok....

pulled the SU. As BusDaddy initially responded, I didn't reinstall it so that the float would not brush against the tank wall. Pulled it, reoriented, replaced wires, boom. Good to go.

Took a stick measurement while I was in there to gauge how well the gauge works. Its still spot on.

Thanks for the help, gurus.