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General Category => Yamaha FJ1100 / FJ1200 Running Problems => Topic started by: SpiderFJ1200 on July 01, 2023, 10:39:02 AM

Title: Fuel gauge failing
Post by: SpiderFJ1200 on July 01, 2023, 10:39:02 AM
I can't imagine the problem is with the float, but my fuel gauge has started either showing between half a tank and empty, even when full. It randomly moves around. So for now, I'm relying on the fuel light to know when to refill the tank. Any ideas as to where to start troubleshooting this?
Title: Re: Fuel gauge failing
Post by: Motofun on July 01, 2023, 10:52:23 AM
A bouncing fuel needle is usually a symptom of a loss of the damping fluid in the back of the gauge.  There is a fix for this that involves refreshing the mineral oil fluid.  I've found that just using the tripometer like i've done for years and years works just as well.  I don't think I'd trust the fuel gauge anyways.
Title: Re: Fuel gauge failing
Post by: red on July 01, 2023, 07:01:41 PM
Quote from: SpiderFJ1200 on July 01, 2023, 10:39:02 AMI can't imagine the problem is with the float, but my fuel gauge has started either showing between half a tank and empty, even when full. It randomly moves around. So for now, I'm relying on the fuel light to know when to refill the tank. Any ideas as to where to start troubleshooting this?
Robert,

Sounds like a flakey ground connection.  Connect a dedicated ground wire temporarily, from the sender ground to the meter ground.  If that cures the problem, clean and/or replace the OEM wire ends and connectors for the sender/gauge system.  Do the same with the sender wire itself, if necessary.
Keep us posted.
Title: Re: Fuel gauge failing
Post by: SpiderFJ1200 on July 02, 2023, 02:04:43 PM
Quote from: red on July 01, 2023, 07:01:41 PM
Quote from: SpiderFJ1200 on July 01, 2023, 10:39:02 AMI can't imagine the problem is with the float, but my fuel gauge has started either showing between half a tank and empty, even when full. It randomly moves around. So for now, I'm relying on the fuel light to know when to refill the tank. Any ideas as to where to start troubleshooting this?
Robert,

Sounds like a flakey ground connection.  Connect a dedicated ground wire temporarily, from the sender ground to the meter ground.  If that cures the problem, clean and/or replace the OEM wire ends and connectors for the sender/gauge system.  Do the same with the sender wire itself, if necessary.
Keep us posted.

This sounds like it's likely the issue with the way it behaves. Since it reads way below empty, needle pointing straight down and only occasionally coming up a bit into the normal operating range. I'll trace those wire(s), clean the contacts, and report back soon. Thanks!