How accurate is trip computer?

[TeryT]

I'm all jazzed as I went to pick up my V8 2003 4Runner Sport V8 yesterday. What an awesome vehicle!

I was wondering a couple things: How accurate is the trip computer on it? It was saying that I was averaging about 23 MPG on my 5.5 hour trip home. I don't know exactly how much gas or how far it had gone when I picked it up.

Another dumb question: the book says for 4x4's to lube & re-torque the drive shaft & propeller bolt(s). Is that as easy as it sounds?

Thanks!!!

Tery

 

[boston_kevin]

it's not accurate

Almost everyone here has come to the conclusion that the trip computer for MPG is about 10% off (roughly 2 to 2.5 MPG higher than actual). Still, if you are getting 21 MPG for a V8, that's awesome!!

 

[TeryT]

Re: it's not accurate

Almost everyone here has come to the conclusion that the trip computer for MPG is about 10% off (roughly 2 to 2.5 MPG higher than actual). Still, if you are getting 21 MPG for a V8, that's awesome!!

Thanks! Is there any way to recalibrate the computer?

Also, how close to actual is the range? If it says "0" am I going to run out of gas within minutes?

 

[boston_kevin]

no easy way to recalibrate

There were a couple of members here looking to offset the trip computer Average MPG reading... See this thread:

http://www.toyota-4runner.org/showthread.php?s=&threadid=5786&highlight=MPG

Also, when the Distance to Empty reads 0, you still have about 3 gallons left in the tank. It is best to avoid running it to this level because this amount of gas is needed to lubricate the fuel pump located in the gas tank. If you run the level too low, you run the risk of damaging your fuel pump which would then require replacement (I would estimate this at ~$500).

 

[MicaBlue03]

TeryT, I don't think there is a way to fix the MPG optimism of the trip computer. Just subtract 2MPG from what you see and you'll be darned close.

As for the "miles remaining" display, that is conservative. Seems like there are usually a couple of gallons remaining in the tank when the computer says you're about to run out.

About the propeller shafts, it's not too difficult, but there are some things to learn. This is not the best place to discus it--just do a search in the maintenance forum and you'll see information from me and others.

 

[Pinuz]

Mine is in KM/l and is off by 14-16% (Canada)

 

[BigDogMoney]

One of the flaws of an otherwise exceptional vehicle is the computer. There a numbers of threads on this site that attest to the frustration of 4R owners and the lack of accuracy from the MPG estimates. Why put something into a vehicle that simple does not work? I've observed mine being off by about 3 MPG. It kind of makes you ponder if Toyota put the same kind of quality assurance in other features of the car.

 

[MicaBlue03]

Quality problems or just deliberate optimism?

BigDogMoney, I share your frustration, but have a specific reason to doubt this inaccuracy indicates a quality issue. If it were a quality problem, the accuracy of the computer would be pretty darned variable, even if it was always optimistic or pessimistic.

Instead, it seems that the vast majority of people find the computer to be 10-15% optimistic, with little accuracy effect from the engine and the type of driving. If Toyota changed the computer software to read 13% lower than it does right now, we'd be raving about how accurate it is.

The mileage of the 4Runner is pretty good for the kind of vehicle it is, but perhaps Toyota is relying on (uninformed) drivers who don't make the actual calculation for some positive mileage spin.

 

[TeryT]

My local dealer says they can hook it up & tell what kind of mileage it is actually getting, then check the trip computer against that. Not sure what happens after that.

 

[Faeylyn]

A lot of people have found the computer to average down over the long haul. Reset it and it pops back up, but will eventually settle down to less than it started at.

 

[TeryT]

A lot of people have found the computer to average down over the long haul. Reset it and it pops back up, but will eventually settle down to less than it started at.

So how often should I reset it to get it to correct itself - and how long will that take?

 

[Faeylyn]

Resetting it doesn't correct it. Resetting it makes it wipe it's memory. Resetting it makes it less accurate. In any case though, it's probably always going to be 10% or so off. If you have a GPS, you can get the real mileage. Or, if you know the actual distance between two points. I'm not sure how to get it to be more accuate though.

 

[MicaBlue03]

Trip computer vs. speedo accuracy

I've used a couple of different GPS units to check speedometer accuracy on the 4Runner and have been impressed. It's consistently about 1% fast at highway speeds, or significantly closer than 1 MPH to true speed. That's as good as one needs to be be, IMHO.

Anybody else got reliable speedo accuracy figures to report?

 

[TeryT]

Re: Trip computer vs. speedo accuracy

I've used a couple of different GPS units to check speedometer accuracy on the 4Runner and have been impressed. It's consistently about 1% fast at highway speeds, or significantly closer than 1 MPH to true speed. That's as good as one needs to be be, IMHO.

Anybody else got reliable speedo accuracy figures to report?

I have noticed when I'm on cruise control on the flat highway, the speedo & the trip computer average MPH don't match exactly. This is after resetting the average speed on the computer. One or the other is off about 2-3 MPH.

 

[carina71]

Mine, for my V8, is typically off by 10%--unfortunately the wrong way.

 

[jasonb]

Re: it's not accurate

Almost everyone here has come to the conclusion that the trip computer for MPG is about 10% off (roughly 2 to 2.5 MPG higher than actual). Still, if you are getting 21 MPG for a V8, that's awesome!!

If this is the case, then why don't I find anyone talking about a class-action lawsuit against Toyota? Don't get me wrong, I love my new truck, but my buying decision was definitely based on the MPG readout during my test-drive. I reset the MPG before I started the test-drive and I was blown away by the fact that I had achieved better MPG than either number on the window (City or Hwy). After driving my truck for a few weeks, I 100% agree that my MPG displays about 2MPG higher than I calculate at each fill up. Since the MPG seems consistently accurate (but 2MPG high) I am very suspicious that Toyota purposefully calibrated the computer to the high side to fuel sales... Over the life of the truck (200,000 miles), this 2 MPG discrepancy will cost us $2,778 (at $2.50/gal). Thoughts? :bs: :bs:

 

[Iowa4Runner]

Re: Re: it's not accurate

If this is the case, then why don't I find anyone talking about a class-action lawsuit against Toyota? Don't get me wrong, I love my new truck, but my buying decision was definitely based on the MPG readout during my test-drive. I reset the MPG before I started the test-drive and I was blown away by the fact that I had achieved better MPG than either number on the window (City or Hwy). After driving my truck for a few weeks, I 100% agree that my MPG displays about 2MPG higher than I calculate at each fill up. Since the MPG seems consistently accurate (but 2MPG high) I am very suspicious that Toyota purposefully calibrated the computer to the high side to fuel sales... Over the life of the truck (200,000 miles), this 2 MPG discrepancy will cost us $2,778 (at $2.50/gal). Thoughts? :bs: :bs:

Well it certainly is annoying that the MPG readout is ~10% off, and it's not exactly a shock that it errs on the high side. As far as lawsuits go, I think you'd have a tough time proving Toyota had intent to deceive, especially since they posted the required EPA estimated MPG numbers on the vehicle. Toyota doesn't make any claims about the MPG computer's accuracy and I doubt there are any federal requirements for non-critical instruments such as these. In the end Toyota would say they made an imperfect instrument and they're sorry for any inconvenience they've caused. It stinks but there isn't much we can do to Toyota I'm afraid.

I didn't expect the MPG readout to be perfect but after a while I got fed up and refused to accept such a large error. I decided to get adventurous and made some mods. If you're really really bent on fixing it you can get the error down to about 1%, but it's a bit involved.

 

[JB.]

Re: Re: it's not accurate

If this is the case, then why don't I find anyone talking about a class-action lawsuit against Toyota?

You're kidding, right? This is the legacy you want to leave with your first post?

 

[Mashimaru]

Its true that the mpg computer is off by some percentage, but it doesn't bother me. Its not like i have my eyeballs glued to that screen all day long, it updates itself every 30 secs or so..

If you want to do something about it, go for Iowa's route of fix..

 

[TeryT]

To be more accurate: the trip computer over-reports by around 7%, and the odometer under-reports by about 3%. Put them together, and this is where the approx. 10% error comes from. (checked several times with GPS & mileage markers)