tminus3

So guys I just want to know as a bottom line, is it possible to fix the fuel economy related problems with an ECU change? That is my only complaint about the car. All I want is to be able to get about 22-23 MPG!

So, is it possible to do it with ECU? I read all the threads on the fuel situation, but nobody seems to come out and say "yes ecu flash will fix this problem, if mazda wants to do it"

What are your thoughts?

-Abhi

RobDickinson

Although I dont have much mechanicaly expertise i think that taping up the fuel injectors on rotor 2 should result in a big saving in fuel costs.

Gord96BRG

Yes, an ECU flash would fix this problem, if Mazda wants to do it.

The issue is that they had to richen the mixture to ensure that the catalytic converters would last the required 100K miles, so they may not be able to do it and remain emissions-compliant.

Read the thread called "official word from Mazda about dyno'ing RX-8" (the 6 page+ thread). In there, forum member canzoomer has detailed his ongoing tests with a replacement fuel controller which leans out the mixture and regains 20 hp and reduces fuel consumption. He is planning to sell those programmed controllers as a kit for somewhere around $750 US. That will achieve mostly the same effect as a re-flashed ECU, but you won't have to wait to see IF Mazda will actually do anything.

Regards,
Gordon

HottRodder

From the 'Tustin Mazda RX8 Event thread in the West RX-8 Forum

"ECU Reflash for CEL issue - Again service manager knew what I was talking about and had the PCM reflashed. I now have a underhood sticker with "Authorized Modification PCM reflash number N3-H6-18881-J". I'm hoping they snuck a fuel map reflash for the milage/power issue in there, I know it's a long shot."

tminus3

Ok these sound like very positive comments. I am getting a warm fuzzy that I might be able to get some relief here. Its just very disturbing that no matter how "grannie" I drive the car I can't get past 20 MPG. I shifting just before 3750 RPM and keeping the car under that in all gears; still only high 18 MPG! so they should have put the stats as

13/18

not 18/25!!! its a blatant lie and false advertising, even if they have a disclaimer in the sticker!.

Sorry I'm getting a bit carried away. I had a 1998 Mustang Cobra (V8 and all) .. if I drove it gently...I could easily get 23 MPG! That was fine for me, I didn't mind driving it slow when I wanted to conserve a bit. But the Mazda doesn't even give me that option!

Other that that, this is truly a poor man's exotic! :D

-Abhi

Reeko

In My case, I have never gotten >17MPG.
On the good side, even when I was really hot-rodding it, I got about 15.5, so there was little variation. Typical is about 16.5.

I have yet to go on any trip that would allow for long, hiway cruising to try to get 20.

tminus3

I only do highway! Less than 5% of my driving is city. best I have is 18.8 MPG...

I'm don't so much want this thread to be about the mileage problem, we all know that is a problem. I want to find out more about the possiblity of fixes. Legitimate fixes from Mazda or aftermarket. Not, drive slower (because I can't drive it any slower than I am), or use this type of gas, etc

mikeb

I'm going to tustin mazda for 2nd oil change on saturday and I'm gonna ask if they will reflash mine.

tminus3

Great! I'm looking forward to hearing what the dealer says. Quick question, is the reason for shifting before 3750 RPM, so that we avoid opening another intake or something? this is what i am assuming. If that is the case, then can they reprogram the intake to open at 4500 RPM giving me some room to shift and to cruise.

Zio

umm is this a joke?

tminus3

I hope not!!! I just finished taping my injectors!


:D

CraziFuzzy

Keeping the rev's down isn't necessarily going to improve your fuel economy... the position of the gas pedal has a much larger impact on it... (well, while accellerating that is)... Just because the 2nd ports open up, does not mean the car uses more gas, it simply means that the engine can get the air easier (if the throttle is open enough) Basically, drive how it is comfortable, but don't race off of every line... you don't HAVE to beat that SUV to the next light just because you can, that is the type of driving that kills mileage. If you HAVE to drive like that, than odds are, you will HAVE to pay for more gas. And yes, I know the car should get better mileage than most are getting, and that it IS running very rich, but accellerating a bit slower will save some gas, regardless of how rich it is running.

blizz81

Have the Mazdaspeed Protege owners experienced an increase in fuel economy after their ECU flash? Seems like roughly the same situation to me. I thought I had heard slightly better fuel economy, but if I did, it was hearsay.

O.R.A.

Yes, there are some reports of improved fuel economy or at least a belief that it has improved, from people that drive Mazdaspeed Proteges after their reflash.

Some quotes from the Mazdaspeed Protege forum on www.mazdamp3.com :

"I have about 200 miles on the flash and it runs great. Gas milege is up too..."

" I have the re-flash and its great..and I also noticed the fuel economy seems better..."

"I got a 20% increase in as mileage on the first tank after the flash. My light always comes on around 280 miles, but it came on at 315 yesterday. I was even running it harder after the flash, I am back to driving normal this tank to see if the mileage gets even better."
(Note: That is not a 20% increase. My math says 12.5% improvement on his range before the light turns on.)

harwax

Does it matter if you have an automatic or stick for the ECU Flash (that dealer might do) to maybe make a difference in gas milage.

thanks

o_town_racer

FYI....my usual mileage city/hwy is around 18 MPG. Highway only is around 22 MPG. I can live with that. It's not optimal, but not as bad as some folks are reporting. My worst/best range is 17-23. I'd sure like to see Mazda admit this as a problem and let us know if a fix is in the works.

tminus3

can you tell me your shifting habits? I would be satisfied with 22 on highway. I can barely keep it at 18 on highway. I shift 1-->2-->4-->6 each shift is just where it crosses 3750 RPM. I'm telling you I'm annoying on the Highway, people are giving me dirty looks and I still only get 18 MPG!

LL7

Canzoomer reported that the engine is running leaner above 3750 so I would expect better milage there. This may be why all attemps at granny driving give no benefit - the car is rich in the granny RPM range.

jonalan

Why would Mazda admit there's a problem, if there is NO problem. You're getting 17-23 mpg - where's the problem? That's EXACTLY what the engine was designed to get.

jonalan

My god - this is a sports car (kinda)! Stop "grannying" it. Drive it like it's meant to be driven.

I drive mine hard - high revs, redline often - and I'm averaging 19.7 mpg with 3100 miles on it. "Grannying" the car may actually be part of the problem - just a thought.

Acceleration may not have as big a role in lower mpg than highway cruising speed. Try keeping your cruise speed below 70 mph and see if that helps with mpg.

Pulsr

damn straight thats how i drive and im rocking the 18 mpg =0

Reeko

OK,
My last tank I tried to granny it, Wherever possible shifting below 4K (ussually 3500). It got me nowhere, same 17MPG i Normally get shifting at 6 to 7K.

I do notice a drop if I am pushing really hard, allways redlineing. I get about 15 MPG.

So it seems to me, unless I get a chance to cruise a long hiway trip, that I should just enjoy the car. Drive hard/have fun...

tminus3

Point well taken folks! :D I only wish I had the choice of 22-23 MPG if I wanted it. Seems like everybody is pretty much stuck at 18-19 MPG.

Lets just "Zoom-Zoom" and forget about the "Cha-ching Cha-ching" :D

mikeb

went today to tusin mazda for second oil change and asked if my ecu could be flashed and they said no problem.

jdl

did they? and do you know under what TSB/problem they listed it?