HELP! Extremely bad MPG!!

J

juancasilva

New member
I have a 2011 5th Gen SR5, the on board computer is showing Avg. 9.7 MPG on the city and 11 MPG on highway! It has been like that for many months, but I just realized how crazy that is! I lifted 2.5 inches with a body lift, slightly bigger tires and a brush Gard at some point but nothing extravagant. Also I have to say that 3 months after I purchase it Pre-owned in PA on 2012 with only 32K Miles, I moved to Azerbaijan (little country between Russia and Iran) Because of my job and off course I always take my T4R with me so for the past 3 years I was using the “best” gas available claiming to be 97 Oct. but I have many friends who complaint about the country’s bad gas and the effect on their vehicles. the engine runs super smooth and there are no noises. Now I moved again, now to South America along with my 4Runner and the gas prices are really high!! So I can’t take this anymore. I will try to clean the AMF sensor and if that doesn’t work I plan to clean the injectors and clean the Oxygen sensors. Also I have an Actron scanner but I have no idea how to tell if the sensor readings are off or not because there is no error code and I have no other T4R to compare it. Any ideas?
Thank you All
JC
 
Register to hide this ad
Have you actually done a good old fashioned fill it till full, record mileage, use down to 1/4 tank, record mileage and fill it till full and record gallons and then divide?

Don't assume the computer is 100% correct. They calculate AVMPG and distance to empty based upon the injector pulses (and maybe even more) and are not perfect.
 
Blitzkrieg said:
Have you actually done a good old fashioned fill it till full, record mileage, use down to 1/4 tank, record mileage and fill it till full and record gallons and then divide?

Don't assume the computer is 100% correct. They calculate AVMPG and distance to empty based upon the injector pulses (and maybe even more) and are not perfect.
Click to expand...
Injector pulses?
 
7b1b21e88d75c6dfa46d286866bd9e43.gif
 
1engineer said:
Injector pulses?
Click to expand...

Yeah. Injector pulses.

My unnamed non-4Runner toy that I put a fairly high end turbo on which required larger fuel injectors I started noticing really weird AVMPG and distance to empty numbers on but didn't think to much about it.

I never really knew exactly what parameters the ECU/ECM took into account when calculating AVMPG and distance to empty but sure as shit, after much digging I discovered that it's pretty common that the ECU/ECM picks up on the injector pulses (fuel squirts to simplify) to calculate what it is telling you.

Check it out. I am not blowing smoke up anybodies skirt. ;-)
 
Blitzkrieg said:
Ummm. No. Do some research and you will feel foolish for posting George.

;-)

Not my first rodeo, cowboy.
Click to expand...
My response was because that there are other threads that are about the EXACT same issue and there is no need to start another. I browse this board almost everyday and it gets annoying at times to see the same stuff posted again and again. I don't know how 1engineer mods this forum, props.
 
mcox522 said:
My response was because that there are other threads that are about the EXACT same issue and there is no need to start another. I browse this board almost everyday and it gets annoying at times to see the same stuff posted again and again. I don't know how 1engineer mods this forum, props.
Click to expand...

When I see a post that says "Injector Pulses???" and you following up with George Costanza - what would your logical conclusion be?

I was just throwing out information I have garnered working on motors over the last year with serious HP (twice what the 4Runner 4.0 has with 2.4 liters) and saying there are a LOT of things most people who think they know ECM/ECU's don't.

If you get annoyed, leave. You have no contract here.

I have never once read about somebody talking about what really, truly makes the computer tell you how it derives AVMPG or distance to empty. If you have, post the link and settle this.
 
Blitzkrieg said:
When I see a post that says "Injector Pulses???" and you following up with George Costanza - what would your logical conclusion be?

I was just throwing out information I have garnered working on motors over the last year with serious HP (twice what the 4Runner 4.0 has with 2.4 liters) and saying there are a LOT of things most people who think they know ECM/ECU's don't.

If you get annoyed, leave. You have no contract here.

I have never once read about somebody talking about what really, truly makes the computer tell you how it derives AVMPG or distance to empty. If you have, post the link and settle this.
Click to expand...
Wow, relax. I'm not going to get into an internet war over something that was taken out of context by you that I already explained had nothing to do with your post.
 
mcox522 said:
Wow, relax. I'm not going to get into an internet war over something that was taken out of context by you that I already explained had nothing to do with your post.
Click to expand...

I am relaxed. If you read what I said, I don't remember ever reading anybody getting into detail about the ECM and sensor relationship to the detail I am talking about. So it's not the same old, hashed over shit.

I have learned some pretty interesting things lately about the ECM/Sensor relationships.

We have no issue.
 
Blitzkrieg said:
Have you actually done a good old fashioned fill it till full, record mileage, use down to 1/4 tank, record mileage and fill it till full and record gallons and then divide?

Don't assume the computer is 100% correct. They calculate AVMPG and distance to empty based upon the injector pulses (and maybe even more) and are not perfect.
Click to expand...

Why are you guys feeding the troll? So much for 35 posts before starting a thread rule. :noidea:
 
1engineer said:
Injector pulses?
Click to expand...

I did notice that when I tried to figure out how the 4th gen's Average MPG is calculated, somewhere in the literature they mentioned that #1 Fuel Injector Pulse Width was used among other variables for calculations. At first I thought this was rather odd, but it makes some sense as that would be a way the vehicle would know how much fuel it is physically using since injector pulse width is modulated by the ECM and assuming all systems are functioning correctly, it can easily be used to calculate how much physical fuel is flowing into the engine (I do not believe the fuel system controls individual injectors, but rather over all pulse width, I could be wrong on that and would have to check when I have time/remember to.)
 
A lift is going to drop your fuel economy, after that it is pretty tough for anybody to trouble-shoot the issue over the internet.

Hilly terrain? Lead foot? Heavier tires? Low air pressure? Carrying lots of unneeded junk in your trunk? Other mechanical issue? Roof rack? Bad gas? All of the above?
 
BlackWorksInc said:
I did notice that when I tried to figure out how the 4th gen's Average MPG is calculated, somewhere in the literature they mentioned that #1 Fuel Injector Pulse Width was used among other variables for calculations. At first I thought this was rather odd, but it makes some sense as that would be a way the vehicle would know how much fuel it is physically using since injector pulse width is modulated by the ECM and assuming all systems are functioning correctly, it can easily be used to calculate how much physical fuel is flowing into the engine (I do not believe the fuel system controls individual injectors, but rather over all pulse width, I could be wrong on that and would have to check when I have time/remember to.)
Click to expand...

The pulse widths are usually controlled by banks (left and right side of the motor). This is related to the fact that there are two oxygen sensors to use as feedback loops.
juancasilva said:
I have a 2011 5th Gen SR5, the on board computer is showing Avg. 9.7 MPG on the city and 11 MPG on highway! It has been like that for many months, but I just realized how crazy that is! I lifted 2.5 inches with a body lift, slightly bigger tires and a brush Gard at some point but nothing extravagant. Also I have to say that 3 months after I purchase it Pre-owned in PA on 2012 with only 32K Miles, I moved to Azerbaijan (little country between Russia and Iran) Because of my job and off course I always take my T4R with me so for the past 3 years I was using the “best” gas available claiming to be 97 Oct. but I have many friends who complaint about the country’s bad gas and the effect on their vehicles. the engine runs super smooth and there are no noises. Now I moved again, now to South America along with my 4Runner and the gas prices are really high!! So I can’t take this anymore. I will try to clean the AMF sensor and if that doesn’t work I plan to clean the injectors and clean the Oxygen sensors. Also I have an Actron scanner but I have no idea how to tell if the sensor readings are off or not because there is no error code and I have no other T4R to compare it. Any ideas?
Thank you All
JC
Click to expand...


If I was concerned about a bad injector or debris in the screens... First thing I would do is use a scanner of some sort to check long term fuel trims...

Another thing I would check (as I've heard of these having major mpg impact on 1grFe with no lights...) is the PCV valve. Just replace it, since it is so cheap.

Finally, hand calculate your MPG to get real data.

Also, what is up with a 2.5" body lift. That is pretty much impossible on a 5th gen. Did you mean suspension lift?
 
Last edited:
You must log in or register to reply here.

Members online

Total: 440 (members: 4, guests: 436)

Forum statistics

Threads
278,304
Messages
3,554,041
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top