99 Blzr LS - Fuel Level Question after new pump

So I get this new fuel pump (the one with the lifetime warranty) and all is good, truck runs perfect...but notice that now the gas gauge moves faster as if to use more fuel than before.

Prior condition: fill tank, needle goes above Full by 1/8" and stays there until about 70-100 miles then begins to decline. At registered 1/2 tank it's at about 175-200 miles then from 1/2 tank to the "Low Fuel" it would drop in 100 miles.....seems weird but that's what I have lived with...

Current Condition: new fuel pump so I know that had to slide off the float level and install it on the new one, OR I in fact have the whole new assembly....don't know yet. Now tank level drops at more a linear level an begins to drop around 30 miles and hits 150 at half, 250 at 1/4....

Not sure what's going on....but gonna ask if they swapped out a whole new assy or re-used my old fuel float system.

Any one experience anything like this or any other thoughts ?

Possible reason why :

Seems when they put in the pump they put in a whole new assy as a unit. More up-to-date, and possibly more accurate....

:eek7:

did you buy the truck new?

could be after they changed the pump/screen/filter.
more gas is flowing than before.....
i experienced what i believe to be something similar after my pump was replaced.....
i did notice more power......which i believe is due to better fuel flow........
and i too have about 250 miles at 1/4 of a tank.
mine is a 93 "the box truck" :)
i would think your year would be a lil more aero dynamic......and get a lil betta mpg.
also how much did u pay for the job......
to replace the whole float/fuel line assembly...adds like 200 more to the job...from what i was told...
i paid 250 for my job....with out the new assembly.
otherwise it would have been almost 500.....
plus if you dont watch whats done ...who knows..
if they actually replaced it...wether they say they did or didnt.....
could be the old unit...and when they moved it out of the tank..it changed the way the float sits...
i dont really know.....
youl have to ask the guy who did it.

Because you had this done at the dealer, you most likely got the whole pump assembly (based on what you stated the cost at). The pump alone would have only been ~$100.00 at the dealer, while the assembly is ~$500.00. Dealers never take the least expensive way out.

I experienced a similar result with the new pump I put in my '97, although my pump is a Carter, not Delco. Before replacing the assembly, I had installed a new level sensor unit that also gave a more linear result.
(BTW, the sending unit senor is a bit more robust on the Cater unit compared to the Delco unit, the fingers on the Delco unit are quite flimsy, The Carter fingers have riveted weights on them to keep them in contact with the carbon ink)

Because GM has a known problem with these units for '97 models, the newer level sensor has a different carbon sensor layout on the sending unit that I'm sure has been incorporated into all of the current units.

Like you, I no longer sit at the full mark for over 100 miles only to see the gauge drop like a rock for the next 150 miles. My gauge comes off the full mark at about 30-40 miles.

Because you had this done at the dealer, you most likely got the whole pump assembly (based on what you stated the cost at). The pump alone would have only been ~$100.00 at the dealer, while the assembly is ~$500.00. Dealers never take the least expensive way out.

I experienced a similar result with the new pump I put in my '97, although my pump is a Carter, not Delco. Before replacing the assembly, I had installed a new level sensor unit that also gave a more linear result.
(BTW, the sending unit senor is a bit more robust on the Cater unit compared to the Delco unit, the fingers on the Delco unit are quite flimsy, The Carter fingers have riveted weights on them to keep them in contact with the carbon ink)

Because GM has a known problem with these units for '97 models, the newer level sensor has a different carbon sensor layout on the sending unit that I'm sure has been incorporated into all of the current units.

Like you, I no longer sit at the full mark for over 100 miles only to see the gauge drop like a rock for the next 150 miles. My gauge comes off the full mark at about 30-40 miles.

So far it moves off of full at about 35 miles , 160 @ 1/2 215 @ 1/4.

What do you get for a range on a full tank ? I was getting about 280-300 but now I am not sure...

I am wondering if I should invest in a professional injector cleaning at this point.....

So far it moves off of full at about 35 miles , 160 @ 1/2 215 @ 1/4.

What do you get for a range on a full tank ? I was getting about 280-300 but now I am not sure...

I am wondering if I should invest in a professional injector cleaning at this point.....

I average between 15-19MPG, depending on the time of year and what type of gas formulation the State of Wi. mandates. (reformulated in the winter months, crappy mileage- thanks Chicago) 50/50 highway/city driving. Reformulated gas ended Apr 1st, mileage jumped up to 19mpg.

I run my truck down to 250 before refueling (1/8 on the gauge, this actually leaves about 4 gallons in the tank)
I got used to refueling at 250 miles because I drove the truck for three years without a working gauge. Old habits are hard to break.

Thanks for the information.

I drove to 222.3 miles which registered a quarter of a tank, then refilled with 11.471 gallons which registers 19.38 mpg...so it's working, just looked weird...

Thought maybe I was losing gas somewhere, but everything is bone dry and mileage is the same, just the gauge is different readings....

after i got my new fuel pump and assembly my mpg went from 15-18. same driving conditions, temp, and driving area.