Fuel Sending Unit/Gauge - SOLVED

[RAMurphy]

Well, exhausted my troubleshooting with tank installed on truck. Going to drop it and continue from there. However, I did order another fuel pump assembly so I will have it on hand.

 

[ncalvo]

Well, exhausted my troubleshooting with tank installed on truck. Going to drop it and continue from there. However, I did order another fuel pump assembly so I will have it on hand.

My experience isn't as drastic in level changes as yours but my fuel gauge about half the time does not track accurately. It is slightly off, and sometimes drifts to correct over time. I had my fuel pump replaced 11 yrs ago and I plan on replacing it again this year as a preventative measure, I saw rock auto had a delphi pump with an 'oe fix' which I believe addresses an issue with the float

 

[swathdiver]

Some random and crazy numbers/readings. So like I said in my last post, for whatever reason my scan tool reads that the fuel tank capacity is 21.6 gallons, i know that is incorrect. When my gauge indicated full the volts were 2.90 and the indications for fuel level remaining 21.6 gallons. When the gauge indicated slightly less than full (between 3/4 full and full) I had 1.84 volts and 17.4 gallons remaining. When gauge indicated slightly less than 3/4 tank, I had 1.92 volts and 15.1 gallons remaining. Closer to half a tank - 2.02 volts and 12.9 gallons remaining (at 60% fuel tank remaining).

Are you using an app like Torque and an OBDII adapter? That one I know asks for the tank size and it may have a default number. A Tech-2 should read it correctly.

 

[RAMurphy]

My experience isn't as drastic in level changes as yours but my fuel gauge about half the time does not track accurately. It is slightly off, and sometimes drifts to correct over time. I had my fuel pump replaced 11 yrs ago and I plan on replacing it again this year as a preventative measure, I saw rock auto had a delphi pump with an 'oe fix' which I believe addresses an issue with the float

I went with the delphi pump this time. It was delivered yesterday.

 

[RAMurphy]

Are you using an app like Torque and an OBDII adapter? That one I know asks for the tank size and it may have a default number. A Tech-2 should read it correctly.

I essentially work on all of ours and my kid's vehicles. As of today that's 8 different makes/models. So, I'm using a XTOOL bidirectional scanner which allows me to utilize the features on all these vehicles. Never thought to look to see if I could input the tank size. Will check and see if that is possible. Although, each time I fire this thing up, I learn something new. I also have an OBDII and utilize dash command.

 

[RAMurphy]

Maybe this weekend on the fuel pump, just need to utilize some more of the fuel in the tank.

 

[RAMurphy]

Looks like the weather has warmed up and rainy this weekend. So I'm going to get to dropping the tank. Some final wire checks and then changing out the fuel pump. Prep work today after work (raising vehicle and such) then complete the work on Saturday.

 

[RAMurphy]

Tahoe up on stands. Less than 1/4 tank of fuel. Let's get this done.

 

[RAMurphy]

Tank dropped. Cannon plugs and wiring all looked good. did a little troubleshooting with the wires. Could not find an issue. Removed retention ring and pulled fuel pump. Think I found the problem. Sending unit where float attaches to the unit is extremely loose and a metallic piece in only partially attached. I will try to get a good picture and provide it. New pump installed. Will complete this job tomorrow.

 

[Fless]

I'd be curious if the loose item is something that snaps in or screws on, or just wasn't installed properly (if it's an actual separate piece). Or maybe it's just broken.

 

[RAMurphy]

I'd be curious if the loose item is something that snaps in or screws on, or just wasn't installed properly (if it's an actual separate piece). Or maybe it's just broken.

Tried to take pictures, just wasn't detailed enough. Looks like both - not properly snapped in (the electrical bands) or not installed properly. Definitely significant more play than the delphi set up. I will take it apart and see if I can figure it out. First, we need to see if this new pump assembly fixed the problem.

 

[Scott in AZ]

My 2001 Yukon exact same. Fuel level reads accurately below 3/4-Tank but when full the level and the low fuel warning light are intermittent. Gage will suddenly read low, and warning light illuminates, for a few minutes then returns to normal.

Chevron fuel treatment concentrate didn’t help, but it probably helped the overall fuel system.

Will I need to eventually drop the tank and replace the pump/level sender assembly?

 

[Fless]

Tried to take pictures, just wasn't detailed enough. Looks like both - not properly snapped in (the electrical bands) or not installed properly. Definitely significant more play than the delphi set up. I will take it apart and see if I can figure it out. First, we need to see if this new pump assembly fixed the problem.

Curious. I think you said you replaced it a few years back with an AC Delco, IIRC. Wondering what level of AC Delco.

 

[RAMurphy]

Curious. I think you said you replaced it a few years back with an AC Delco, IIRC. Wondering what level of AC Delco.

Well, I do keep all my records. I will look up when I get a chance. Pretty sure I purchased from Rock Auto.

 

[RAMurphy]

My 2001 Yukon exact same. Fuel level reads accurately below 3/4-Tank but when full the level and the low fuel warning light are intermittent. Gage will suddenly read low, and warning light illuminates, for a few minutes then returns to normal.

Chevron fuel treatment concentrate didn’t help, but it probably helped the overall fuel system.

Will I need to eventually drop the tank and replace the pump/level sender assembly?

To be honest, pretty sure my issue will be fixed with the new unit. But, until I get it hooked up later today, unable to verify right now. My issue just kept getting worse to a point I didn't trust what I was reading and quite frankly it was pissing me off. Hope to mark this one "Solved" by the end of the day.

 

[Fless]

Well, I do keep all my records. I will look up when I get a chance. Pretty sure I purchased from Rock Auto.

Well, if you did, they might warranty it for you. There are several levels of ACDelco quality, but the MU2294 pump shown for the FF engine is the Gold level, one down from Genuine GM. Not sure what came OE with these trucks.

The MU2294 is the same pump my '04 took when I replaced it.

 

[RAMurphy]

Well, if you did, they might warranty it for you. There are several levels of ACDelco quality, but the MU2294 pump shown for the FF engine is the Gold level, one down from Genuine GM. Not sure what came OE with these trucks.

The MU2294 is the same pump my '04 took when I replaced it.

Yes, it was a the gold MU2294.

 

[RAMurphy]

SOLVED. Pump installed and tank back up in place. Wow, much easier dropping the damn thing. Fuel gauge/quantity working perfectly. Filled up. Correct "full" reading then drove for about 50 miles. No issues what so ever. Remained steady with no fluctuations. Didn't mention this in my comments when I replaced the fuel pump almost 2 years ago - but I was having no luck with getting the lock ring off with a screwdriver/punch and hammer - so I purchased a tool. Made removal and install pretty easy.

 

[Joseph Garcia]

Great to read that our issue is solved, and thank you for posting 'solved' in your thread title. Our collective knowledge base has been increased.

 

[Fless]

Thanks for the walk-through and posting the details of the solution.

I had to pull my pump (exactly the same as yours) a couple of years after replacing it, to replace a defective gasket. Not sure if we wrinkled it a little when it went in, or if it was malformed and we didn't notice it. Weird that it didn't cause an evap leak until so long after install.