Fuel Consumption Surge, Possible Reasons?

R

raminux

New member
I recently bought a 2003 4Runner which needed a couple of repairs and fixes. So I took it to the mechanic last week and the following jobs were done:

1- The pipe departing from the main body of the muffler was cut which was welded to its place.
2- rear brakes were replaced: disks, pads and calipers.
3- one hand brake string was replaced.
4- a leak happened in a pipe related to the steering wheel which was fixed.

Now, it looks like there is a sudden surge in fuel consumption. The system used to show 12-12.5L/10km (19.6-18.8mpg). Now it shows 15.9-16.3L/100km (14.8-14.3mpg). I also sense the increase in fuel consumption and I am wondering why this could have happened? Which one of the above repairs could possibly have such an impact. Or perhaps another reason is in effect.

Thanks.
 
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You said something about replacing a hand brake string. I assume this is a parking brake cable. Is it adjusted properly, if not the parking brake could be dragging.
 
raminux said:
I recently bought a 2003 4Runner which needed a couple of repairs and fixes. So I took it to the mechanic last week and the following jobs were done:

1- The pipe departing from the main body of the muffler was cut which was welded to its place.
2- rear brakes were replaced: disks, pads and calipers.
3- one hand brake string was replaced.
4- a leak happened in a pipe related to the steering wheel which was fixed.

Now, it looks like there is a sudden surge in fuel consumption. The system used to show 12-12.5L/10km (19.6-18.8mpg). Now it shows 15.9-16.3L/100km (14.8-14.3mpg). I also sense the increase in fuel consumption and I am wondering why this could have happened? Which one of the above repairs could possibly have such an impact. Or perhaps another reason is in effect.

Thanks.
Click to expand...

Do you know if they happened to have disconnected the battery (which might've reset the stored MPG data)? I think that MPG display is based on a long term average so if it was recently reset it would be starting fresh, so to speak. This might be one cause for the lower numbers.

I would try manually calculating it for more accurate data.
 
eddiebx: Actually they did disconnect the battery since the clock had to be adjusted too. I didn't think the fuel consumption rate is a longterm average and I have mostly been driving in the city since I got the t4r back. I wonder if 14.5mpg is normal or not?

03_4x4Runner: When the parking brake (which I called hand brake) was used and then released before starting the vehicle, I hear a noise coming from the lower part of the vehicle (like something is making a noise while rolling). I am going to the garage again to have it checked.
 
op, is this by the read out ( which isnt accurate anyway) or hand calculated? do you have v6 or v8? imo, with v8, 14.5 all city driving is good. you cant expect high mpg numbers when driving mostly or all city.
 
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yeah my guess is the parking brake is hanging...or possibly the caliper is sticking on one or both sides after the brake job.
 
raminux said:
eddiebx: Actually they did disconnect the battery since the clock had to be adjusted too. I didn't think the fuel consumption rate is a longterm average and I have mostly been driving in the city since I got the t4r back. I wonder if 14.5mpg is normal or not?

03_4x4Runner: When the parking brake (which I called hand brake) was used and then released before starting the vehicle, I hear a noise coming from the lower part of the vehicle (like something is making a noise while rolling). I am going to the garage again to have it checked.
Click to expand...

I believe the reading on the dash is a long term average and not a tank to tank average. If you are talking about this display reading low, I wouldn't worry about it too much especially after you said that the battery was disconnected. Perhaps calculate the MPG by hand for a few tanks and see how that goes.

If you want to check for parking brake drag, jack up the rear and spin the tires. There should not be any excess drag and you should definitely be able to spin the tire by hand.
 
Calculating Mpg by hand instead of using the read out usually puts me at about 2 miles less per gallon than what the computer says. From what i've read this seems to be pretty typical city mpg
 
The parking brake cable is to be replaced. I will next do a manual calculation of fuel consumption and will write it back here.
 
in case its of any interest. http://www.toyota-4runner.org/4th-gen-t4rs/8506-v8-mpg.html if you still do only city & almost no highway, dont be surprised if it comes out less than 14.5 with the hand calculation, but add a little highway mileage, it will go up a bit, & my guess is you will be somewhere in the middle of the avg. v8 mpg. what im saying is, since you haven't had it too long, that the slight dip in mpg may just be a result of the battery disconnect (reset) & mostly or all town driving & may not be the result of something being wrong.
 
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could be a stock calip[er...touch your wheels after a long drive..see if the temp are about the same.
mine dropped to as low as 12mpg on the display meter. and found out my right front caliper was hot..super hot after a few miles drive.....after servicing the caliper....my mileage display now reads 18mpg on intercity and 21mpg on highways..when i reset it...
 
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