Recently, I took my 2004 RX-8 to my dealer to have it serviced per Recall 3305G(Heat Concerns During High Idle). As other owners may be aware, the service included installation of a heat shield near the fuel tank and a reprogramming of the PCM. Prior to the service, I was lucky to get near 350 km per tank. As we don't drive Chevy Sprints and I generally love my car, I was able to live with this economy. Since the service, I'm lucky to get barely over 300 km per tank. I use premium fuel, have the car serviced regularly, and maintain 32 psi in my tires.

I am assuming the PCM was reprogrammed to increase the amount of fuel in the air/fuel mix to result in cooler exhaust temps. Oxygen sensors in the exhaust stream can be used to calculate the air-fuel mix ratio in units (lambda). Maximum power for the RX-8 is generally seen around the 0.92-0.93 lambda range. If the mix is too rich with fuel, the lambda figure will be lower. If the mix is too lean, the lambda figure will be higher, increasing the risk of detonation in the exhaust. A lower lambda figure will often result in both power loss and reduced fuel economy.

I sense the latter has happened with my car. I have contacted Mazda Canada and alerted them to my concern. I was directed to take my car to my dealer to have it checked over and will be doing so this week.

I urge any other owners who have had a similar experience to immediately contact their dealers to have their vehicles checked and to complain if they are not happy with this turn of events. As RX-8 owners, we were not given a real choice on the matter as the Recall letter refers to having the service performed or risking warranty breach. Frankly, it should not be my problem if Mazda designed a vehicle that was not properly designed or engineered. I bought a vehicle that has an advertised fuel economy rating of 12.9 and 8.8 L/100km - I had been living with a figure around 17. It is now slipping closer to 20. This is simply not acceptable. The manufacturer will only pay heed if enough owners raise this as an issue. Please contact your dealer if you have shared my experience and frustration on this issue. Cheers.

 

....ummm....this could get ugly...

Fuel consumption is a topic that has been beaten to death on this forum.

 

I agree - fuel economy has been beaten to death. But there's only so far owners can bend over before they speak out. What's next - square wheels because of concerns the car's parking brake will disengage causing undesired roll?

Mazda already took a hit from its exaggerated horsepower claims after succumbing to the EPA and reducing heat (ie.power/economy) to preserve the life of the CAT-Converter. As many of you are aware, Mazda offered buy backs, free service and cash to many disgruntled owners.

I'm not a mooch looking for a free buck but I (and all of you) paid good money for your cars. Why should we have to take it up the A-- everytime we go to the pump while some Mazda engineer covers his through a BS recall campaign?

We have to get off our butts and do something!

 

Litig8, yes yes, it is not only your car that has incountered this problem after recieving the "R" flash. I to natised a SEVERE drop in gas consumption after having my PCM re-flashed. all i did to recover the problem was reset my ECU after the nex fill up by doing the "reset butten hold" and the "break peddel tap" tricks. If you do this, you problem will be solved and your 8 will go back to the way it usto be. Enjoy

 

^ after the R flash...my mileage went up. It really seems to be a hit and miss kind of thing. I also find it takes a few tanks for the mileage to settle in to something consitant after each flash. It's probable the computer figuring out your driving habits and adjusting to them.

 

Just went in on Friday for a regular service and I did my little bit as far as complain goes regarding the Kilometrage (?) She told me they checked the PCM and that there was no pending updates etc etc.

I had the heatshield recall done about 6 weeks ago, but to be honest my cars consumption has allways been in the 20l/100km range anyway....So i kinda thought I will just have to put up with this. I love my baby enough that I would easily live with this though I have to agree the idea that all this waste of valuable resources could be lessened depending on some programmers discretion bugs me a little

Only issue I have with complaining to the dealer is how is it ever going to make any difference if all the dealer does is "reassure" you??? Isn't this something a petition of some sorts could with instead?

There is allways waiting for 6 months on the waiting list and then pay 5000 over invoice for a PRIUS.....

 

"Recently" would mean you are now using thin, weak, light, less power "winter" gas - it is full of butane and heptane this time of year, I know, I make it. For the Canadian market, it gets really light September to March, to make sure your car will start at minus 40*.

Your mileage for the rest of the trip suffers, but that's tough.

The "R" flash was great for my mileage, I got it early.....your mileage may vary!

S

 

I guess another thing is that 32 PSI is a little low for winter driving ... remember PV=nRT. If it gets cold like here in Calgary, you're probably running less than 32psi which could affect your fuel economy. The standard for winter driving is 36psi

 

Point noted BlueFrenzy. I actually run fill to around 35-36 in my Toyo Garit HTs - but as you say, it reduce to about 32 between fills.

 

I had the exact same experience. I picked up the car in June and since then was able to do 320-350 km per tank, since the recall I went over 300 once. I talked to the dealer, but they asked me to "give it few more months" to see if the mileage will improve.....

 

Litig8,
Care to acknowledge this post? You should know already that mileage always decreases in winter due to the winter gas and the harsher operating conditions. In other words - coincidental to your receiving the R flash.

If I were feeling rude, I'd say "suck it up, buttercup!". But I'm not (feeling rude), so I'll just say that you haven't enough data to positively correlate your mileage decrease exclusively to the R flash independent of the environmental conditions and fuel quality changes. Don't bother harassing your dealer about this - just drive and enjoy your fine vehicle!

Regards,
Gordon

 

Gordon, I will acknowledge the thread. The hypothesis that poorer economy is attributable to "winter gas" definitely has it merits. To suggest it would economy would be reduced by approximately 50km/tank [I know this unit of measurement isn't particularly accurate but it's based on what my tank normally fills to] - a 14-16% swing - is somewhat specious and scary.

The "winter gas" theory would also carry a lot more weight with me if I had the same experience last winter - I did not. I consistently got 350 km/tank last winter, notwithstanding running on winters, presumably with "winter gas". Unless some oil patch insider is willing to chime in otherwise, I would assume this year's winter gas is substantially similar to that of last year's.

Please understand, this is not a "whine". I'm well aware of the hundreds of threads that have been posted regarding fuel economy issues. Each vehicle and region are bound to have differences. Based on some of the responses to my query, I may well be in left field as not all vehicles have reacted similarly. That does not change the fact that the economy of my vehicle has been decreased 14-16%, most likely by a manufacturer's campaign. I imagine the largest buttercups in the world would think twice at sucking anything in the circumstances.

 

I appreciate your considered response. However, I have to point out another issue with your campaign (or concern) - "km per tank" is NOT a valid measure of consumption - there is no such unit of measure as a "tank", unless you run it bone dry every time. Otherwise, there is NO valid repeatability. As an engineer, all I could suggest is that you take a minute per fillup to do the real math, and calculate a proper litres per 100 km. Your refueling volume could easily vary by a litre or two, which obviously affects your km per "tank".

 

good point because we all know how accurate that fuel guage is.

 

Am I the only one that got super excited that perhaps there was going to be a recall to fix our crappy gas mileage?

Someone change the subject line, i'm so saddened and let down that i just may off myself.

 

I just don't think the mileage is that bad? It’s not great...but not that bad. I think people have this idea that because of its small size it should get huge mpg. WE BOUGHT A SPORTS CAR PEOPLE!

Rotaries have traditionally delivered less than impressive mpg so live with it or sell it.



btw...hey Gord any chance I'll ever get my picture viewing status back or am I permanently on Santa's bad boy list. I'd pm you, but I can't do that either.

 

I do agree with you, but i read something the other day that cracked me up...

1.3L Rotary

4 cylinder torque
6 cylinder HP
8 cylinder thirst

lol...

 

funny...but it is what it is and people should know better before they buy.


the advantage of a rotary has never been the power and mpg but the small size that let's it sit low and back on the frame for great handling characteristics.


Plus it revs to 9000rpm. That counts for something.

 

dont forget the noise.... :D

Damnit, the subject line has yet to be changed, i wonder how many more poor souls will fall victim to its lies.

 

Cleoent: Sorry for the misleading subject line - purely unintentional. If it's editable/removable, I'm all for it.

Gord: I'm aware km/tank is not a valid measure of consumption which is why I qualified my comments. Even with a litre or two's variation between fill ups, the post-flash deviance from posted mileage is still statistically significant. Obviously, my references are only to my tank/gauge: no one elses.

All readers: This has been quite the experience. Some have questioned the validity of my observations [ie. what's a "tank" of gas; winter fuel; psi in the tires]. To them, while your points are all valid, my comparisons are based on all of those items having been kept equal enough over two winters that a suggestion a loss of 50km+ per tank is attributable to them is not helpful.

Finally, while some owners have expressed guarded concern, the general consensus is "live with it". It reaffirms what I have always known and also believe: RX8 owners will put up with a lot to drive these machines. Raising a potential issue with a manufacturer is responsible and potentially helpful to others. That was my only motivation for posting the thread in the first place. I will still follow up on my individual car with the dealer and would invite anyone who has shared my experience to do the same. Enjoy the ride. Out.

 

The "live with it" consensus doesn't arise from indifference to your issue, but from familiarity with it AND with Mazda's response! Many of us who have shared your experience over the past 2.5 years (this is my 3rd winter with the RX-8) have already raised this issue with our dealers and with Mazda. Aside from the reflash that everyone gets, Mazda won't do anything about it. They've certainly heard enough from owners worldwide and in negative press that I'm sure if they could do something about it, they would!

I wish you the best of luck in your pursuit of a resolution; I just advise you to not hold your breath...


I don't have the power to see or alter those settings! You need to find Omicron or zoom44 for that. Actually, I'll ask them on your behalf - shall I assume that you promise not to 'recruit' for RX8web via PMs here if they give PMs back? (That was Ryan's reason for removing them)

 

Gord, I'm heartened to hear your take on this. I'm a newbie on the forum circuit and don't profess to be a techie/engineer/tuner. The fact I haven't kept two years of fuel economy stats should attest to this. I also did not intend to come across as a know it all or the first person to notice the mileage issue. I've read old Canada forums as well as myriads of U.S. ones. As you've eluded, many people wiser and more experienced than me have chimed in on the issue.

Though I'm not holding my breath, I will challenge Mazda Canada (or Japan or U.S.) to explain themselves. If I am able, I will gladly share their comments with this forum. I fully understand and agree with your sentiment that "living with it" is not indifference. However, I must respectfully disagree with any conclusion that owners familiar with a "problem" should bear its financial responsibility simply because the manufacturer won't or can't address it. Surely, that responsibility falls on the shoulders of the manufacturer and owners should be compensated accordingly. I sincerely appreciate all of your and other forum members' comments.

 

Rotten, you're good to go! Toadman was feeling all Christmas-y!

Mazda will tell you this isn't a "problem", but a "characteristic". The EPA mileage ratings are just estimates, and are generated by the manufacturers by following a very precise drive cycle on a chassis dynomometer - during which the emissions are measured and the fuel used back-calculated from that! If you're upset that the actual mileage doesn't match the official estimates/ratings, be glad that you didn't buy something like a Prius or Accord Hybrid that is supposed to get fabulous mileage - those vehicles are even further off, percentage-wise, than the RX-8 is in their real-world consumption.

The manufacturers are NOT responsible for ensuring that their vehicles achieve the EPA ratings in the real world. They aren't responsible for the inaccurate test cycle that generates mis-leading numbers, so are not responsible for differing real-world results.

 

I did experienced a sudden drop in EPA right after the recall. It wasn't happened recently nor in exterem cold. I do belive the newflash contributed to the change and I all to have an answer from Mazda.