Hey guys. I've been having a very erratic fuel gauge issue as of about 2 months ago. My fuel level would register full, when in fact I knew it only had 1/2 a tank or so. Then 5 minutes later it would be pegged on full. Under a 1/2 tank the gauge would read any where from 1/2 to empty from 1 minute to the next. So last week I decided to drop my tank and take a look. I was thinking maybe my fuel sender was broken, maybe a loose wire in the tank, or even that my float had dropped off in to the tank. After dropping the tank, I removed the PK-Up and sending unit and everything was intact. I placed my ohm meter on the sending unit and it checked out fine. So I took the Pk-up and rolled back up underneath the truck and plugged it back in. I had my son turn the key on and off while I moved the float to different levels in order that it would register. It registered empty, 1/4/, 1/2, 3/4 and full just fine as I moved the float to those levels. If you leave the key in the run position and move the float, it won't register or better said, the in cab gauge will not adjust with the movement. You have to turn the key off move the float and hold it there, then have your helper turn the key on and the gauge will show the position that you've moved and held it at. I simply removed the plastic cover from the sending unit, and sprayed it down real good with electrical contact cleaner. I didn't scrub the copper contact area at all. I was concerned that scrubbing might remove more than I wanted to, and really mess things up. I attached an Ohm meter and checked resistance thru out the float travel. All checked out good and I reinstalled it. So now my fuel gauge is working as it should be. I did make a video while I ohmed the Sender Unit thru it's travel, but for some reason it won't load.
https://www.youtube.com/watch?v=QZPX...ature=youtu.be

 

Hey all. I was wondering if any of you are running a Scangauge. After the repairs I made to my sending unit, the fuel gauge reads as it should, but I noticed that my Fuel level on my scangauge does not show any values. I recall that it did use to show my fuel level before I started having the erratic fuel readings. I figured that once I made the repairs to the sending unit that my scangauge would show my Fuel level again, but no go. I'm wondering if maybe my Fuel gauge in the cluster is broken, but the fuel gauge is reading true now. I believe that the fuel level from the sending unit goes thru the ecm and then to the gauge cluster, correct? Just trying to figure out what could be causing this malfunction in my Scangauge. The Scangauge is plugged in to the OBD port, which in turn get's it's info from the ecm. So I'm kinda stumped..

 

When you left the key on and moved the float and it didn't move, it's because of the "anti-slosh" feature keeping the gauge from bouncing all over the place... not sure if it's the ecm or a separate module... I'm not familiar with the scangauge so I can't comment there...

 

So it's your understanding Stebs, that there is in fact an anti slosh module on our trucks? I thought it was only the gas rig's that have an anti slosh module that's located on the back of the gauge cluster. I looked back over the pictures I took of my gauge cluster when I had it out about 3 months back, and it didn't have one. Unless it's located in a different location on a diesel.

 

That I couldn't tell you.., all I know is something keeps the gauge from bouncing around...

 

My guess is just filtering on the gauge signal.