’04 RX8 won’t idle after battery change.
 

I’ve searched here and everywhere looking for a solution to this. Basic problem is that my battery died, so I replaced it and now my 8 won’t idle once warmed up. I don’t find any evidence of the usual culprits, vacuum leaks, fuel supply problems. And it runs as strong as ever. First thought was the ECU needs to reset, but it’s been many drive cycles now and still have the problem.

Symptoms are: Won’t idle after warm when driving. Will idle if started cold and the pedal is not touched. Runs fine otherwise.

Timeline:

Tuesday morning after holidays, needed to jump start in the morning to get to work.

Tuesday evening started fine at work, but wouldn’t do more than dim the dash lights after driving 30 miles home.
Had battery load tested and replaced it.

Wednesday, started up and drove to work (mostly expressway) every time after getting off the expressway that she was expected to idle simply went to zero rpm. Thought, oh the ECU just needs to figure out what I’ve done, by not having a battery for a couple hours. Always restarted, but wouldn’t stay running unless I give it some gas. If I can hold my foot in the right position 800 rpm is easily maintained, but remove that foot and she lands gently at zero. Also if you can get your foot back on the gas before zero is reached the engine will recover.

Thursday same as Wednesday, but now I’m paying very close attention every little thing looking for clues. Cold idle seems to be 200-500rpm slower than I remember before the holidays. Always seems to run fine cold. Runs fine all the time just won’t idle. Pulled a P0506 (idle to low) I’m not really surprised with this one.

Friday same as the Wednesday and Thursday.

Saturday morning, decided to do an experimental test. I pulled the negative off the battery and waited a few minutes. The reconnected the battery. Without using the accelerator at all, I started the engine and let it worm up. Five minutes came back from the house (it’s cold in Chicago land in January), not quite completely warmed up, in another 5 minutes fully warm, shut her off and went inside for an hour. Cam back and repeated the procedure starting and warming up without touching the gas two more times. Along the way pulled a couple codes. More P0506 and a P2070. P2070 SSV stuck open cleared on it’s own. Did investigate the secondary shutter valve and all seemed free and able to move, but I didn’t dismantle enough to get in and see if the switch was working properly as it wouldn’t have cleared on its own. At least that was my logic.

Stats:
• ’04 Purcchased Sept ‘03
• 6 SP MT
• ~112k miles
• Had all the flashes possible done back when she was under warranty. I’d have to look to see which exact revision I’m on.

have you tried the ecu reset? (pumping the brake 20 times)

Not yet. Is it really different than disconnecting the battery? Thought it just reset part of the ECU?

I will try it. At this point I don't want to take it to a dealer with out knowing what's going on..

if you can, disconnect the bat for 24 hours, then hook it up and try the reset, like this, post #3

Still won't idle
 

Hi all,

Thanks for the help so far, but I still have the problem.

Does any one have any suggestions on who best in Chicago's western suburbs to take this to?

I've moved to the stage where I'm assuming the worst things I can think of so it's time to get a real expert.

Thanks again for the help! Ideas and additional trouble shooting help will still be appreciated but she is my daily driver and at some point I'm going to be pushing my luck driving with the left foot working both the brake and the clutch.

http://www.evolvchicago.org/phpbb/index.php Check out this site.. this is where all the chicago people hang out at

BlueZoom The same thing has just happened to me and I dont know what to do. I have a 2004 manual rx-8 with 78000 miles. Iam in Ny and the battery went dead. I went and bought a new battery and It turns on no problem and drives no problem just like yours. But as you said it just shuts off when its supposed to idle. I checked my filter and throttle body and nothing looks out of the ordinary. Iam going to try and pump the brakes 20 times like it was written here. Any help would be greatly appreciated.

Changing the battery, and the dead time around it, causes a reset. It seems the last thing learned is to idle. Charles Hill came across a post work test that said basically idle for a long time from warm-up. I will try that for next. For starters, clean the MAF, it could be part of the problem that the ECU had figured out before it was reset. Then start the car cold, and let it idle. Do not go anywhere, just give it a few minutes. See if it figures it out. If it does not, help. I sat in a parking lot for about 5 minutes, foot on the gas, slowly reducing the idle speed as the ECU figured it all out. At the end, no problem. Next time, I start it and let it idle for 5 minutes.

Good luck.

Same problem appeared to me when I changed my battery. All I had to do was to complete 3-4 driving cycles (turn on the car, drive it for a bit, turn off the car = 1 cycle). The car had to relearn its fuel trims. After I did the above the car turned back to normal.

Problem is that those cycles can be a pain if you need the car to idle. Granted, it works. But some kind of assisted learning process would be cool, and would mean you do not have to wait for the car to cool between cycles.

^Wait for the car to cool between cycles? Why? You want to do this process only when your car is warmed up so you do not risk flooding the engine.

From what I have read, a complete cycle includes warmup. If I get a lot of short cycles, it sometimes works, last time it did not. That is what drove the just teach the darn thing to idle approach. Cars may be different though. Next time I will try to idle for 5 minutes and see if that does it. If the quick cycles worked for you, great.

I had problem with my sun visor falling down because the bar had stiffened up and had to take it off and when I took it off I shorted the two wires for the light i then went through the fuses to see which one had blown. But I was checking the ones in the engine compartment in error not the fuses in the foot panel until I realised the internal lamps fuse was there. I drove home fine until I got to a traffic light and she cut out every time i took my foot off the petrol pedal. I took it to a Mazda dealer who wanted to replace the coils and charge me over €1000!!. I told them about this thread and they ignored me so I took the car back without changng the coils to try it myself. I tried the following turn on the engine left it idle for 10 mins ac off and then ac turned on ac for 5 mins without turning off the engine and then drove off. And the car is hopefully now back to normal it hasnt cut out since!!. Nice job on the advice it saved me €1,000 on something which still would n't have fixed it. The power of the internet!!

I noticed on one of the threads someone said the warranty on the RX8 engine is 8 years?? is that true?? I asked the dealer and they said 3 years or 100,000KMs. The car is at 93,000KMs and 5 years old so I am wondering about the dreaded compression problem if it occurs am I able to say it is 8 years warranty to Mazda and under im under 100,000km. Does anyone know if it truly is 8 years and where can I find that statement on the net about that Mazda warranty for the rotary engine?

The warranty in North America is 8 years or 100,000 miles, which ever occurs first . Warranty elsewhere is not as great/long as the US , Italy 5 years, Croatia 3 years etc .

I love this forum. Someone's 8 invariably has had the same issue as mine.

Hey guys. Same thing happened to my 8. Usually it corrects itself after one day but this time it's taking too long. Is there a proper procedure to replace the battery? This seems to happen every time I loose power (or my sunvisor falls
off)

Just want to make sure:
To reset the ECU, unplug battery for a few minutes,
connect terminals
then pump breaks 20 times then start engine?

...with key in on Position?

Coincidence...lol

Hello , well I was just told that after replacing the battery the car has to run at idle for a min of 10 mins without being disturbed until it recalibrates itself. If you don't give it enough time it will take longer to do so on its own. If not might have to disconnect the battery again wait till it erases any programming and start again, and let it run at idle for 10 mins. Hope this works for you.

Exactly the same problem. The battery negative terminal was disconnected a couple of days ago. and then reconnected. Drove well before disconnecting and drives well after disconnecting and reconnecting. Only issue is that it stalls when engine is warm (that is, when the temperature gauge reaches close to midway). This is a big surprise to me. I must have given it about 4 full cycles till now (that is start, warm, run, switch off and cool down being one cycle). Not sure how many more cycles the ECU needs to relearn what it has forgotten. I can't say if it is getting better, but I have learnt to adapt to it quite well already. I now use both my feet to drive (its an automatic, so usually only right foot is used). What I do is.. even when I have to brake at traffic lights or something.. I maintain a small amount of pressure on the gas, so that the engine keeps revving and my left foot on the brake. The minute I need to move, I let the brake go and she roars ahead. Everything else seems normal in the car. Any pearls of wisdom from anyone?

Back when I had a vacuum leak (did not know it at the time), I had this problem. My fix, until I found and fixed leak, was to start the car cold, when it started to struggle press the gas pedal a bit to bump it back up to the RPM where it did not struggle, then every minute or so, back off a little bit, until it struggles, then pick it up a few hundred until it figures that RPM out.

I also recommend checking plugs, wires, coils and stuff like that. When those were on the edge, I had the issue as well. Bottom line is something is going on that the ECU cannot figure out, and it is a pretty smart ECU...

good info on this thread. i changed the battery yesterday and today its not holding idle.

i'll wait a few days to see if this idle figures itself out. thanks for the earlier posts

UPDATE: i drove the car a second time today, and the idle is fine.

keep on getting a 6061 2559 code intake tuning inlet valve is there a quick fix