Fuel gauge.
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Joined: Oct 2025
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Fuel gauge.
Hey gang how you all doing? I've got an '89 f150 lariat XLT 3.9, 6 cylinder 5-speed overdrive manual transmission, lockout hubs. Standard Bench seat cab and a short box. Got about 105,000 mi on it. It's been sitting for the last 5 1/2 or 6 years. Had the transmission and all out of it cuz the starter bolts snapped. My brother took it out cuz I had shoulder replacement surgery and couldn't do it at that time. Well 5 and 1/2 or 6 years later I decided I'm going to get the son of a bitch going. And guess what I did. I had to find all new bolts. Everything from the flywheel to the u-joints. I took the interior out and put some sheet metal down on the floor on the driver side because my foot could go right through if I wasn't careful. I did a real hack job because hopefully later I can actually get a floor pan and weld it in. I just wanted to get it running. Anyway to make this long story a little bit shorter. I've got it running now and it runs like a top. The engine is not an issue at all. It runs perfect. The transmission works perfect. The starter works perfect. The only problem I'm having that's irritating me is the fuel gauge is jumping all over the place. Sometimes it works and sometimes it doesn't. Now. Most of the time it doesn't. It just bounces around way over full. I'm pretty sure it's a ground or something I'm just looking for suggestions on where to look first. This is the first Ford I have ever worked on or owned. I have been pretty much GM most of my life. Which is 67 years now. If anybody's got some wizdom they'd like to pass along, I'd appreciate it. Lord knows I need some. Thank you guys for allowing me in your thread. It's the first time I've ever done this. I know that's what they all say.
Last edited by ReefinRon; Nov 3, 2025 at 06:27 PM.
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Joined: Jul 2007
Posts: 3,806
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From: Cape Girardeau MO
Welcome to the site! Buncha knowledgeable folks here, and occasionally I try to play that part.
Not discounting the wiring or grounding issues especially now given the age and its idle time, had a similar issue with my '89 wayback - stayed way overFull forever then within ~20-30 miles would start bouncing around then dropping like a rock to about 1/4 where things stabilized.
Right, wrong, or otherwise - figured it was the sending unit in the tank.
Given the challenges of replacing, opted to just deal for what turned out to be more than a few years with it since the last quarter tank was where I got interested and put filling up high on the list of things to do for that fuel pump cooling wisdom. Kinda kept an idea of how many miles I'd get between fill-ups and planned fuel stops accordingly.
Aside from all that, perhaps inspect the wiring coming off the tank for any damage such as mice-gnawings or pinchings, maybe wiggle and jiggle the wires to see whether the gauge readings change.
Not discounting the wiring or grounding issues especially now given the age and its idle time, had a similar issue with my '89 wayback - stayed way overFull forever then within ~20-30 miles would start bouncing around then dropping like a rock to about 1/4 where things stabilized.
Right, wrong, or otherwise - figured it was the sending unit in the tank.
Given the challenges of replacing, opted to just deal for what turned out to be more than a few years with it since the last quarter tank was where I got interested and put filling up high on the list of things to do for that fuel pump cooling wisdom. Kinda kept an idea of how many miles I'd get between fill-ups and planned fuel stops accordingly.
Aside from all that, perhaps inspect the wiring coming off the tank for any damage such as mice-gnawings or pinchings, maybe wiggle and jiggle the wires to see whether the gauge readings change.
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Joined: Oct 2025
Posts: 9
Likes: 4
From: NJ
Fuel gauge
Hey gang how you all doing? I've got an '89 f150 lariat XLT 3.9, 6 cylinder 5-speed overdrive manual transmission, lockout hubs. Standard Bench seat cab and a short box. Got about 105,000 mi on it. It's been sitting for the last 5 1/2 or 6 years. Had the transmission and all out of it cuz the starter bolts snapped. My brother took it out cuz I had shoulder replacement surgery and couldn't do it at that time. Well 5 and 1/2 or 6 years later I decided I'm going to get the son of a bitch going. And guess what I did. I had to find all new bolts. Everything from the flywheel to the u-joints. I took the interior out and put some sheet metal down on the floor on the driver side because my foot could go right through if I wasn't careful. I did a real hack job because hopefully later I can actually get a floor pan and weld it in. I just wanted to get it running. Anyway to make this long story a little bit shorter. I've got it running now and it runs like a top. The engine is not an issue at all. It runs perfect. The transmission works perfect. The starter works perfect. The only problem I'm having that's irritating me is the fuel gauge is jumping all over the place. Sometimes it works and sometimes it doesn't. Now. Most of the time it doesn't. It just bounces around way over full. I'm pretty sure it's a ground or something I'm just looking for suggestions on where to look first. This is the first Ford I have ever worked on or owned. I have been pretty much GM most of my life. Which is 67 years now. If anybody's got some wizdom they'd like to pass along, I'd appreciate it. Lord knows I need some. Thank you guys for allowing me in your thread. It's the first time I've ever done this. I know that's what they all say.
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