Just wondering if anybody knows or has information regarding the gauge sweep test.

My brother in laws 2004 F150 has a gas gauge that generally works somewhat when the tank is full but does not work at all or gets stuck in various positions when it's below half tank.

I did a gauge sweep and all of the gauges, except the fuel gauge, sweep full path like they're supposed to. Fuel gauge just kind of trembles or moves a little and then trembles. If the gauge needle doesn't sweep during the test is that an absolute conviction of the gauge/cluster itself or can problems with the fuel pump assembly mounted sending unit still cause a gauge to not work correctly during a gauge sweep?

I'm thinking the gauge sweep eliminates questions about whether the various sending units are to blame by bypassing those circuits for the purpose of testing actual gauge function?


BTW, I've checked all the wiring below the drivers seat, connectors, tested, etc., and from the data I could find, the sending unit seems to test ok although I do get some fluctuations. I think he plans to replace the fuel pump assembly anyhow, just as a preventative measure, but I have a strong feeling that won't solve the gauge problem.

 

https://www.ford-trucks.com/forums/1...e-problem.html
https://www.ford-trucks.com/forums/1...ge-issues.html
https://www.ford-trucks.com/forums/6...gas-gauge.html
Search is your friend.
I run ethanol free gas and injector cleaner every other tank and have not had this problem in a long time.

 

Yeah? Except that none of those threads has anything at all to do with my question other than the gas gauge being suspect. I am getting the proper readings on the wiring, at both sides of the connector, underneath the drivers seat against the frame rail, like I said. It does not SEEM as though the sending unit is responsible for the problem and I am already well aware of the TSB on the in tank unit regarding fuel properties.

Maybe read the thread before you bust somebody down for not searching first, because I can assure you that I spent the better part of a day searching and reading every even semi-relevant thread and couldn't find a single one that definitively said anything at all about what the RESULTANT BEHAVIOR of the gauge sweep should or should not indicate.

 

Give forum sponsor www.circuitboardmedics.com a shout, they fix those things for a living.

I've worked on plenty of instruments in the past. Based on that, I'd suspect a faulty meter movement.