2000 GMC erratic gas gauge

[wsl1971]

I just so happen to have my 98 blazer in the shop today. My fuel gauge was doing the same thing and finally yesterday the fuel pump went. My mechanic told me it was the sending unit making the gauge act like that. So $900.00 later i have a new fuel pump and no crazy fuel gauge. I say keep good records of your fuel and miles and just prolong the agony until the pump dies.

good luck
bill

 

[bricker]

fuel gauge

I have a 2005 Envoy with the same problem. Techron brings the needle up to 1/8 tank even when full. Then it registers empty the next day. Cryin shame they can't get it right after all these years!

 

[Wayne02]

Some pricing investigation on the parts (I'll do the install myself) reveals the least expensive to be ebay for an OEM replacement for $180. Comes with pump, strainers, level sensor, tank seal / o-ring. Plus $13 at napa for the wiring harness that is recommended to be replaced at the same time.

Shucks, Napa and GM parts direct have the oem replacements for $333-$352 or so.

Shucks also has a Carter aftermarket kit with harness for $274.

All of these only had a one year warranty though. I did not see any (including the $500+ Bosch units) that had more than a one year warranty.


Good call on removing the bed for the install. I looked at that today and it certainly seems to be the most expedient method. Looks to me like the bed just needs to be walked back a couple feet and may be able to be set/rested on the rear tires. However, I don't know how much that short bed weighs but I suspect it is more than just my son and I can handle. I think I can back the truck under the hoist arms, sling the bed from the tie-down points in the four corners and use the hoist to lift the bed off the chassis. It will be nice not having to mess with draining the fuel, tank straps and hose routing.

 

[bayfisher]

You originally said that you have a lift and a tall trans jack in your shop.

I drop tanks all the time. All you have to do is, raise the truck,put your trans jack under the center of the tank, loosen the 2 hose clamps on the fill and vent tube, pull the driveshaft(gives me room to get a stool to stand on), Remove the two bolts holding the straps that hold the tank to the body, and slowly lower the jack.

You can lower the tank to the point where you can remove the pump assy from the tank without fully removing it. Just make sure you have the tools to disconnect the fuel lines from the pump assy.

The harness problems others have spoke of was if your pump has the flat straight across plug, replacement pumps come with a more squared plug which requires cutting the old harness and wiring the new squared harness to match the new pump assy.

One last word of advice, DON'T go with an airtex or master replacement pump. Put an AC/DELCO in and forget your problems for years. Or you could go cheap. But how many times do you want to change out that pump just because they offer a lifetime gauranty(SP?) Thats why i put ac/delco in my 98 Z71, 6 years and still going strong.

 

[USAF385]

I had something like this happen once. At first there would be small movements of the needle. Eventually they got more and more extreme. It would sink all the down to empty and then jump to full. The entire time I'd be driving it would be doing this. Finally it "snapped" and stuck on way past full. The car ran fine the entire time, and ran for another 3 years. I never bothered having it fixed or finding out what it was... my trip odometer let me know when it was time for gas.

 

[Class III]

I had the same problem on an '88 K-5 Blazer, '93 1500 4x4 and an '02 2500HD 4x4. Loose ground wire on the '93, easy fix. The Blazer and the 2500HD both had a broken baffle in the tank. The spot welds that hold the baffle in place break and the baffle slides around in the tank causing the guage to go crazy at times. Replaced the tank on both the '88 and the '02 with aftermaket tanks and the problem went away. On the Blazer I went with a high capacity poly tank (45 gal). It hung down about 4" lower than the stock tank. Only drawback to the poly tank is that it is more suseptable to puncture than a metal tank. I fabricated a skid plate for it using corregated steel and angle steel and bolted it to the frame. With the extra 14 gal of gas in the tank it was nice being able to fill up every other day. That beast got 12 MPG in town an 14 HWY.

Class III

 

[2Loud4You]

Wayne, be careful using some cheap ebay part. If it doesn't work then you have to do it all over again it might be a pain to return for a working one. I say spend the money and get one from a store near you. Sometimes peace of mind is worth more money. I've done enough to know that sometimes brand new pumps go out.

 

[1968hawkeye]

I have a 2005 Envoy with the same problem. Techron brings the needle up to 1/8 tank even when full. Then it registers empty the next day. Cryin shame they can't get it right after all these years!

I had a similar problem last Christmas with my 2006 Envoy. We were on our way to OK City to visit our son and stopped for gas somewhere on I-40 in TN. Filled up, started the Envoy and the gas gauge was on E and the little yellow light was on. Well, I knew I had gas so we hit I-40 again, as we drove the gauge gradually worked its way to to what seemed like an accurate reading. This didn't go away. When we got back to NC took it in and they replaced the sending unit. Thank goodness, it was still under warranty.

Hawkeye

 

[41]

Good call on removing the bed for the install. I looked at that today and it certainly seems to be the most expedient method. Looks to me like the bed just needs to be walked back a couple feet and may be able to be set/rested on the rear tires. However, I don't know how much that short bed weighs but I suspect it is more than just my son and I can handle. I think I can back the truck under the hoist arms, sling the bed from the tie-down points in the four corners and use the hoist to lift the bed off the chassis. It will be nice not having to mess with draining the fuel, tank straps and hose routing.

Mine is a 1990 with a short bed. I used the mail man to help me lift it off and set it in the yard. Not sure you can slide it back because of the bumper.

It is so much easier working from the top versus dropping the tank. I did a search of the message boards and that was the preferred way to do the job.

I only replaced the fuel pump and it was about $70 at Advanced Auto Parts.

My fuel pump got weak because the fuel filter was not changed as often as required. Overall it was an easy job.

41