how to test gas gauge??

[1ugly88]

ok, ran the truck out of fuel today cause it seems that my gauge gets stuck at a half tank. it will work fine for the first half tank the just stops at the halfway mark. it did this a few months ago but started working again after about 2 weeks. how do i go about testing it to figure out if it's my sending unit, cluster or just a bad wire? info.... she's an 88 scsb converted over to a 93 cluster with tach. did the swap about 3 years ago and was working flawlessly till a few months back.

 

[joshjuniorr]

was actually searching for this topic lol. Hopefully someone comes up with something. Sounds like if it stops working at half a tank its a sending unit..stuck float maybe....

 

[NAST96]

^^^Agreed. Im also having the same problem only mines sticks at 3/4 tank. Works great for the first 1/4 but stays at 3/4. Once in a blue moon it will work but rarely. my specs are 96 ecsb 5.7. I changed the fuel pump a while back. And it worked great for a few months. Now its doing the same thing as 1ugly88's. Im guessing sending unit?

If anyone can shed some light on this id also appriciate it.

--Jarred

 

[joshjuniorr]

mines just pegged out at over full lol. i'm assuming its probably the sending unit >.<

 

[NAST96]

i really dont feel like pulling my tank down agian... So i just live with it and run the trip meter. But id like to know if mine is the sending unit.... just in case i ever have to get in there agian.

 

[1ugly88]

i really couldn't say what happened to mine cause about a month ago it started working again. so my guess is a bad wire or connection somewhere.

 

[oneluckypops]

been a long time since Ive seen an 88. If it was newer you can test the sending unit with a scanner, but with it being an 88 I cant remember if you can or not I am thinking NOT. So if memory serves me correctly GM sending units are measured in ohms (0-90 ohms) find the correct wires for the sending unit at the tank and measure the ohms when you fill it up and again when you think its around E or even 1/4 tank. compare the readings to the normal values and replace if nessicary

 

[Tinbender59]

to test fuel guage

you can test the gauge, the sender is a drop to test situation.

1. to test your gauge "any GM": get under the vehicle.
2. find the gauge wire, look at schematics:
3. unplug it at the most convenient place
4. turn the ign switch on: gauge should read - pegged out full
5 now short the wire on the dash side to ground: turn on ign switch should read - dead empty.

if that all works out ok the most common "bad gauge reading issue" is
a bad ground to the sender unit. if you can reach up on top of your tank feel for the wire that is connected to the metal tank plug that is the top of your sending unit. Trace it out and it usually will be corroded or broken at or near the grounding point, i have personally enjoyed this before

 

[joshjuniorr]

I thought the ground might cause that..just wanted verification from ppl who have been there done that.when I'm done with my clutch I'll check that wire