my fuel gauge and distance till empty shows inaccurate reading even after i replaced my fuel pump… what could be the issue?

 

What year is the car?

 

2008

 

Im not sure how it works on the 2008 models. But the earlier models had issues with solder joints on the gauge cluster cracking and throwing off the fuel reading.

 

It's basically the same troubleshooting process on the V36 chassis, start by measuring resistance across pins 2 and 5 on the primary harness, pins 1 and 2 on the secondary harness.

If it's sending the correct signal but it's not showing the correct value on the dash it could be either the AC Auto Amp or the instrument cluster on the V36 chassis, you can read pins 2 and 5 on the back of the AC Auto Amp to verify it's getting the right signal. Fuel level goes directly to the AC Auto Amp which then sends the signal via CANBUS to the instrument cluster.

Whereas the V35 chassis it doesn't go through the AC Auto Amp it goes directly to the instrument cluster.

Here's a picture, pictures are good.

 

Also keep in mind there are TWO SENDING UNITS, the pump has the main sending unit, the other "pump looking thing under the rear left side seat" is just another fuel level sender since it's a saddle tank that requires two senders.

 

Where is the AC AutoAmp located ?

I get sporadic inaccurate fuel readings.
It will jump from 100% to 80% (sometimes).
80% to empty works perfectly everytime.
Sometimes it's accurate and works fine from 100% to 80%
I just assume it's dirty and needs to be cleaned.
But with the cold weather outside, I can't be bothered.
It's not that serious.

OP try this :
Try cleaning the contacts from the float level

 

I have better luck using a #2 pencil to clean circuitry contacts like that. It provides a tiny bit of abrasion to remove the crud without damaging anything since graphite is actually an excellent lubricant for some things. Just make sure to wipe it all clean when you're done.

AC Auto Amp is right behind the climate control buttons. It's the climate control computer but it does a LOT more cabin/body related stuff, not just climate control. It essentially is the interface for everything going into/out of the instrument cluster.