MPG goes from 25-30 to 35-40
11-18-2014
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MPG goes from 25-30 to 35-40
So I bought my GFs 2002 Civic LX Sedan off her. It had 140k miles when I got it from her currently has 170k
I have pretty much rebuilt this whole thing. It has a brand new transmission, all seals, water pump, timing belt, struts, control arms, stabilizer links, brakes, rotors, used but clean oem injectors.
Right now there are 2 issues, one is a vibration at 65-80mph but I have a pretty good feelings its the front Axle.
The one that concerns me is my MPG. I replaced the injectors with some used OEM injectors that were cleaned.
I will drive it non stop day after day and get between 25-30 mpg. Sometimes the car after warming up wont start. I will have to flood the throttle in order for the car to start up. This happens maybe twice a month.
Two times now I have let the car sit for 4-8 days while I used a company truck to move **** around. I always leave the gas tank full before I park it.
First time I let the civic sit for 8 days. I came back and I was at half a tank with 284 miles. Filled up because I was worried because I normally only got between 300-350 on 10 gallons depending how I drove it that week. Filled up 7 gallons which comes out to be 40.5 MPG.
After the fill up I drove for the full tank and my MPG dropped down to 30mpg. The next fill up it dropped to 28-30mpg.
So now I went to vegas, drove the GFs car there so the civic was sitting for 4 days. I come back and now I am getting 38mpg.
I am lost.
I have pretty much rebuilt this whole thing. It has a brand new transmission, all seals, water pump, timing belt, struts, control arms, stabilizer links, brakes, rotors, used but clean oem injectors.
Right now there are 2 issues, one is a vibration at 65-80mph but I have a pretty good feelings its the front Axle.
The one that concerns me is my MPG. I replaced the injectors with some used OEM injectors that were cleaned.
I will drive it non stop day after day and get between 25-30 mpg. Sometimes the car after warming up wont start. I will have to flood the throttle in order for the car to start up. This happens maybe twice a month.
Two times now I have let the car sit for 4-8 days while I used a company truck to move **** around. I always leave the gas tank full before I park it.
First time I let the civic sit for 8 days. I came back and I was at half a tank with 284 miles. Filled up because I was worried because I normally only got between 300-350 on 10 gallons depending how I drove it that week. Filled up 7 gallons which comes out to be 40.5 MPG.
After the fill up I drove for the full tank and my MPG dropped down to 30mpg. The next fill up it dropped to 28-30mpg.
So now I went to vegas, drove the GFs car there so the civic was sitting for 4 days. I come back and now I am getting 38mpg.
I am lost.
Last edited by drj1014; 11-18-2014 at 12:53 PM.
12-12-2014
#2
Re: MPG goes from 25-30 to 35-40
It's too bad that the 7th gen forums don't get much activity lately. I'm having problems with fuel efficiency as well, but not like what you're getting. I used to get 44 mpg from highway driving with my 01 civic lx. That was maybe 5 years ago. Today, even with brand new tires, I'm getting less than 38 mpg highway. It's bizarre.
12-24-2014
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Re: MPG goes from 25-30 to 35-40
It sounds like you have 4 issues. Vibration, bad mileage, hard start and leaking fuel.
Did you install the insulator for the injectors? It looks like a thick washer. Have you try swapping in the old injectors and see if it make any difference?
You can download the service manual and go to page 309 for more troubleshooting steps.
Hard starting (MIL works OK, no DTCs
set)
1. Test the battery (see page 22-
79).
2. Check the fuel pressure (see
page 11-131).
Low compression
Intake air leaks
Contaminated fuel
Did you install the insulator for the injectors? It looks like a thick washer. Have you try swapping in the old injectors and see if it make any difference?
You can download the service manual and go to page 309 for more troubleshooting steps.
Hard starting (MIL works OK, no DTCs
set)
1. Test the battery (see page 22-
79).
2. Check the fuel pressure (see
page 11-131).
Low compression
Intake air leaks
Contaminated fuel
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