Higher MPG after fuel pump replaced?

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As I posted in another thread my fuel pump was weak and the Blazer was hard to start.
So the pump was replaced.
I always fill at the same station and divide the gallons into the miles.
Since I've had the Blazer (6 months)the MPG has been in the high 14's.
Today was the first fill with the new pump and I got mid 16's and thats with running the A/C almost every day.
Can fuel mileage increase with increased pressure from a new pump?
 
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Yes, I don't doubt it. Just replaced the fuel pump in the Civic and fuel economy DID jump up about 2-3mpgs, not to mention more power. And yes running the a/c didn't even affect it like it used to! I think it's more about the flow of the fuel to meet demand. I had tested the pressure of the old pump it passed, but it kept leaning out/losing power around 4k rpms. I didn't care what the pressure test said, it was time to replace it. I am very happy I replaced it! Now it's working well..

so again, you're not imagining the increase of fuel economy..
 

measureman

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Oh yeah forgot to mention that it feels a bit more powerful, well as much as 20 year old 190 horsepower at a mile high elevation can be.
 
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exactly.. we're not talking race car power, lol! I've always found if you have more power you always get better mpg's, obvious sure, but thought it was worth mentioning. glad you got it working like it should!
 

measureman

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exactly.. we're not talking race car power, lol! I've always found if you have more power you always get better mpg's, obvious sure, but thought it was worth mentioning. glad you got it working like it should!
It's not fast or even quick but it's adequate.
 
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If these vehicles are DI then it might be that a new-pressure-fuel-pump makes dirty injectors spray better. If that is the case, then it might be that putting a bottle of Red-Line SL-1 in the tank every 10K or 20K miles would clean up those injectors. Also, if they are restricted, cleaning them now may be prevent them from getting soooooo bad that they have to be replaced.

All this is speculation, but sometimes thinking about what might be going on leads one to the correct decision about what to do.
 

measureman

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If these vehicles are DI then it might be that a new-pressure-fuel-pump makes dirty injectors spray better. If that is the case, then it might be that putting a bottle of Red-Line SL-1 in the tank every 10K or 20K miles would clean up those injectors. Also, if they are restricted, cleaning them now may be prevent them from getting soooooo bad that they have to be replaced.

All this is speculation, but sometimes thinking about what might be going on leads one to the correct decision about what to do.
DI?
It's a 2002 with a spider injection system,it's rocking 90's technology.
Prior to having the pump replaced I ran a bottle of Techron and 2 tanks with Marvel Mystery Oil.
Should I do it again?
 
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Better mpg with a new fuel pump can happen. I wonder if the excess fuel was finding its way into the oil, as well as some of it out of the exhaust. I also wonder what a UOA would look like before and after the fuel pump replacement....
 
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Maybe, or could be that plus a combination of other factors. Some vehicles get a little better fuel economy in warmer weather despite running AC more, especially on shorter trips where they go ECM closed loop sooner, oil/transmission fluid thinner, tire pressure rises, and less air resistance with something brick-shaped like an older SUV.
 

measureman

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Maybe, or could be that plus a combination of other factors. Some vehicles get a little better fuel economy in warmer weather despite running AC more, especially on shorter trips where they go ECM closed loop sooner, oil/transmission fluid thinner, tire pressure rises, and less air resistance with something brick-shaped like an older SUV.
My daily commute to work is 2.2 miles each way 5 days a week.
The temp gauge barely hits normal in warm weather and in the winter it goes about 1/2 way to normal.
 
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