Fuel gauge malfunctioning

I just bought a 2000 Blazer 4wd at an auction. It has 97k on it and i had to have the transmission rebuilt. After that, the only problem i notice is the fuel gauge doesnt seem to be working correctly. it works fine from a full tank to a half a tank, but then doesnt go anywere. The other day on a road trip the gauge read half a tank but I had driven 190 miles. Any help you guys could give me would be great. Thanks

Most common cause is sending unit

I agree I have the same problem

I just use the trip meter as my fuel guage

If it is in fact the sending unit you might as well just wait until the fuel pump goes out. Dont you worry because sooner or later it will go out. The just do the entire assembly at once. I just say that because there is really no need to drop the tank if you dont have to. But then again thats just my opinion.

has anyone replaced the fuel pump and sending unit by sawing through the rear floor area? I did that on my camaro by following an internet fixit guide.

will it work on the blazer?

thanks.

I've seen this done, and I have to say its the most stupidest thing you could do. If you have an accident, gas can get in, fire risk, carbon monoxide risk, the list goes on and on....

i tried it on my z28 like this and it seemed to be fine with heavy gauge steel plate, plenty of liquid gasket (red) and I put in 20 sheet metal screws to hold it down. seemed stronger than original body but rollover risk would be higher with the blazer so maybe fuel could get in.

http://www.geocities.com/formulapower2/fuelpump.html

Why saw through the floor when it only involves dropping the tank? Seems to me like it would be more work, not to mention dangerous, to saw through your floor and then have to replace the hole you just cut. ?????

Why saw through the floor when it only involves dropping the tank? Seems to me like it would be more work, not to mention dangerous, to saw through your floor and then have to replace the hole you just cut. ?????

I Agree.
The first time I dropped the tank on my '97, it took me 5 hours from start to finish.
The second time, it took me less than 3 hours from start to finish.

Cutting a hole in the floor, then having to patch it back up is more work than taking the fuel tank out. I can't see any benefit to doing it that way.

rather than call it a hole, i like to think of it as an access panel. i've done fuel tanks on other chevy's (e.g. astro van) and just seemed a whole lot easier to sit comfortably in back working downward than laying under car trying to wrestle the tank upward. as to danger of cutting hole over tank--tank must still be drained and one must be just as careful drilling first hole as placing jack stands on raised car or removing air bag units--if not done carefully, disaster can always occur.

bottom line--sounds like most of you drop the tank.

thanks,

jeff

If and when you decide to replace it, this site has the pump/sending unit for alot less than it would cost at a dealer.

The part# is 25176789

http://www.gmpartsdirect.com/

Yip, sending unit.

The unit in the tank gets stuck at half way or is fouled.

do you have part no for fuel pump also, may as well change that if changing sensor.
thanks,
jhsmith246

It might come as one unit with that year.

Some years the pump was the whole assembly.

Make sure you get AC Delco only for the pump, do NOT cheap out and get Carter or something or you will be sorry.

I just bought a 2000 Blazer 4wd at an auction. It has 97k on it and i had to have the transmission rebuilt. After that, the only problem i notice is the fuel gauge doesnt seem to be working correctly. it works fine from a full tank to a half a tank, but then doesnt go anywere. The other day on a road trip the gauge read half a tank but I had driven 190 miles. Any help you guys could give me would be great. Thanks
Fill it up hit your tripometer and go about 210-220 miles until your pump goes out.

rather than call it a hole, i like to think of it as an access panel. i've done fuel tanks on other chevy's (e.g. astro van) and just seemed a whole lot easier to sit comfortably in back working downward than laying under car trying to wrestle the tank upward. as to danger of cutting hole over tank--tank must still be drained and one must be just as careful drilling first hole as placing jack stands on raised car or removing air bag units--if not done carefully, disaster can always occur.

bottom line--sounds like most of you drop the tank.

thanks,

jeff
What took me the longest about getting it out was getting the gas out because wouldn't you know it was just filled up the day before. Get it off the ground one bolt one nut undo the filler pipes which I already did because that where I got rid of the gas. Drop down the tank and cut the front hose so you don't break ninety degree fitting that you can only get from dealer then let the front down so you can see to unhook gas lines on pump and electric connections and out it comes. Don't forget to get a new wiring harness when you buy your pump.

does anyone know how common this problem is? i have 2 blazers, a 2000 purchased used at 1 year old from enterprise rent a car here in california and a 1999 sold originally in arizona that i bought used when it was 4 years old.

both have the failed sending unit problem which for me is 100% failure rate. when i think about chance of having a sample of 2 cars with failed sending unit i wonder if maybe thats rare or could it be that 75-90% of blazers from that period have this problem. does anyone know what percent of these cars had (or have) this issue?

The problem is common on many GM vehicles. The pivot wears and allows lateral movement, and the bifurcated contacts become weak and lose consistent contact with the resistor array. They can be repaired easily (once they are out) by tightening the pivot and adding tension to the leaf contacts (very carefully). I've done several, but never by hacking a hole in the body structure:

http://72.19.213.157/files/LevelSensor05.jpg

interesting

does anyone know how common this problem is? i have 2 blazers, a 2000 purchased used at 1 year old from enterprise rent a car here in california and a 1999 sold originally in arizona that i bought used when it was 4 years old.

both have the failed sending unit problem which for me is 100% failure rate. when i think about chance of having a sample of 2 cars with failed sending unit i wonder if maybe thats rare or could it be that 75-90% of blazers from that period have this problem. does anyone know what percent of these cars had (or have) this issue?
Well I know out of the last four five if you count mine that has came through my body shop only one of them the gauge worked. I am talking over 90K vehs and the one working had just had a pump replaced and now mine works because I had to replace mine also.:pimp: