2002 Chevrolet Blazer LS Automatic 4WD 4-Door SUV. Spec says it has a 18 Gallon tank but when it reads empty and I fill it up I can only get 10 Gallons in. Please help. Thanks.

 

It could be many things:

Wiring fault from the PCM to the sending unit
Bad ground at the sending unit to the frame
Sending unit
PCM
class 2 com to IPS
IPC

The two most likely causes are first three. If the power or ground wire is corroded and places additional resistance into the circuit then the PCM will see the 240 ohms that indicates empty too soon. That or the sender reostat may be gone.

A first test would be to provide a clean ground at the sending unit when you read empty and see if it corrects to half or so full. Next would be to isolate the power wire and test it. If the tank has to come down to get access then you can test the sending unit while its down. In the meantime, reset your trip odometer every time you fill up and go by that. I do this on every vehicle as standard practice.

Live bait as in google eyes or greenies?

George

 

Mine is doing the same, 2001 ZR2, I’ve put in a new fuel pump with a new level unit, same thing!