2004 Chevy Astro fuel guage

This vehicle is common to have fuel level sensor issues. Which is in the fuel tank. Sometimes if the level sensor is bad it will set a trouble code. Have the vehicle scanned to see if any codes are set.

Take the fuel pump connector loose. Use a resistor on the proper wire terminal, see if the gage reacts properly? Purple wire with white tracer and solid black wire, use proper resistor in between the two terminals, key on. 250 ohm resistor, the gage should show full. 40 ohm resistor, the gage shows empty. If the gage reacts properly, the sending unit in the gas tank is suspect. Radioshack sells resistors, they are cheap.

Have the trouble codes checked, manufacturer specific as well as generic.

Have the charging system professionally load-tested. In particular, the full-load output current must be close to the rated value of the generator, and "ripple" voltage must be low. GM has had a real lot of trouble with their generators since they redesigned them for the '87 model year. It's common to go through four to six replacements in the life of the vehicle. If the generator fails its tests, to reduce the number of repeat failures, replace the battery at the same time unless it is less than about two years old. These generators develop huge voltage spikes that can damage the generator's internal voltage regulator and diodes, and interfere with computer sensor signals. The battery is the key component in damping and absorbing those spikes, but as it ages and the lead flakes off the plates, it loses its ability to do that.

The fuel gauge problem can be a couple things. However, usually the float rheostat goes bad and sends a bad signal. The bad part is the float is part of the fuel pump (not cheap) and the fuel tank needs removed to replace it. Please keep in mind, there are other things that could cause it. None of which are cheap. The rheostat sends a signal to the body control module (BCM) and then it sends the signal to the gauge. Either could be bad too.

The fuel sending unit is part of the pump assembly. They have been known to go bad. Also, check to see if there are any lose connections on the pump wiring harness and check for good grounds.

Hi there,

T you for the donation,

This will be a faulty sender unit with is located in the fuel tank, you will have to get the fuel tank removed and there is a special tool required to unlock the sender retainer before it can be removed, the fuel pump will be mounter with in the sender assembly so this will have to be transferred to new unit.

Mark (mhpautos)

Now wont start can hear fuel pump come on

Do below to determine if its a fuel or spark problem

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, cap and rotor, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing