how do i set up my fuel gauge to work with a blazer tank?

[67cst]

i filled up my blazer tank a couple days ago and the gauge only read half, how do i get it to read full? i think a while ago i read in a post about reseting fuel gauges...im not sure how and id like to get this working asap, when i filled it up i made a 45 minute trip on the highway, the needle dropped 1/8th of tank when i got home, since then ive driven in town maybe 20 minutes and its down another quarter, so 3/8ths of a tank total, for some reason i dont think the needle is accurate, it shouldntve of dropped that soon i dont think, whats the deal with getting this gauge to work right? any help would be great, thanks guys

Derek

[Gee_Emm]

Do you know what type of sender the tank has? There are different ones, for some reason a six cylinder takes a different sender then a v8, auto or manual trannys too. I asked on here before what the difference is but no one knew.

[67cst]

No i dont, when i got the tank it just came with one, maybe ill e mail scotts super trucks and ask them, maybe i need to buy a new one? what size is the tank behind the seat? just curious to how close it is to mine, i was hoping that the gauge would just work, oh well, just another thing to work out

[jhow66]

Did it work right with the other tank?

[SS55]

I have always been told that all of these trucks used a 0-90 ohm sending unit. The differences in sending units, as explained to me, was the size of the fuel line. The I6 and the 2bbl V8 got the 5/16" line while the 4bbl V8 and the Big Blocks got the 3/8" line. And there's also the difference for a behind the seat sender and the Blazer/Suburan sending unit.

[67cst]

i dont know if it originally worked, im sure it did but as soon as we got the truck home i began stripping it, i guess ill have to email the buisness i got the tank from and ask them how i go about getting it to work

[Kas68c10]

I dont think all the trucks used 90 ohms, I think the burbs used 70 ohms, may need to swap the guts odf the sending units in the 2. I am pretty sure I did it, about 3 years ago though, memories kinda hazy, must had a couple of beers doing it !

[jorgensensc]

These are the facts as I know them:
I did a blazer tank swap on my truck and the sending unit sends the same ohms. My guage wasn't working correctly( as I'm pretty sure your's isn't either), and was broken. i bought a good used one from someone on the board and bought a new resistor (white thing on back over the two posts), filled the gas tank up and hooked the gauge up. i used a fork to remove the needle, set it to full (be sure you are not on a driveway with a slant, I had to do it again on a flat surface, Doh), then ground the fuel sending wire going to the gauge (sends the needle to past empty). Then connect it to the sending unit again and make sure it goes back to full. Do this a couple of times to make sure the gauge works correctly before putting everything back together. I did all this using long wire jumpers with alligator clips, so the gauge wasn't actually installed until I was finished. I cannot stress this enough... MAKE SURE ALL YOUR GROUNDS ARE GOOD!!!! make sure the tank is grounded to the frame, and make sure your gauges are grounded good. If you have a partial ground you will fight this all day long.
Sorry to be long winded, but I speak from experience. It took me the better part 6 months to finally get all my gauges restored and working properly. Finally they ALL work like they should. Hope this helps a little.
Shawn

[Kas68c10]

Yep, the grounding issue could be the cause allright,and I could be wrong on the resistance, I am sure I took one apart, but maybe not.

[67cst]

thanks shawn, wow i really dont want to take my dash cluster apart! but i think i might have to on a rainy day, how do i ground the gauge? and also i assume the tank should be topped right off? also for now what i want to know is when i fill the tank the needle reads half full soooo when i am almost empty will the needle be past empty? this is hard to put in words, what im trying to say is will the needle travel the same distance as if it were inthe right position?because i dont know when im empty right now...jeez i must sound like an idiot..lol

thanks

DEREK

[cableguy0]

all gm sending units are 0-90 ohms check your grounds and the gauge could be bad

[jorgensensc]

trust me, you can take a gauge cluster apart in 15 min. (5 if you do it as many times as I have) it's really not hard at all. The way I grounded the cluster was I took the bottom lone post on the fuel gauge and ran a wire from it to the brake chassis part. Make sure it is a good ground first. I did the same with the circuit card. hope this halps a little.
Shawn

[jhow66]

Check out this site:

www.fix-a-gauge.com