three2eight

Hi guys,

I had my RX8 for 3.5 years now. Within these few years, I have changed 4 batteries so far... There are no warning sign or symptom for battery failure and I ended up buying the battery last minute and change it myself. Each time, after the change, there will be engine check light and traction light on. However, after driving the car for half an hour or so, the check light will automatically turn off by itself. However, the lastest battery change, the engine check light has been lighted up for days.

Any idea what could be the problem? I have reset the ECU twice but not successful. Suggestions, anyone?

Jasontan_sg

This is my 2nd battery change, what I have learned is that you should compeletly remove the connector from the old battery and connect back with the new one. Some battery shop used another spare battery to clip on your car battery connector at the side and replace the battery, so that the radio channel will not reset, unfortunately due to your battry weak the sensor signal into your ECU is also weak causing wronge signal to your ECU resulting improper fuctioning with your car, engine light up and sometime RPM are event higher.

If you remove the connector completely without any spare battary support, all electronic in your car will be reset to normal at the same time, then all the senors will be working properly and provide correct or accurate reading to the ECU to work properly.

I suggest you instal a battary volt meter to ensure no last minu battery change.

King105

That is exactly right, as with my experience.

Normally there will be signs before the battery kapoo - especially when you start the engine. The crank might sound weak, or you need to turn ignition key again. Not sure if you observed any?

King105

three2eight

Hi Jason,

Thank you for your feedback. I will consider your suggestion on a battery volt meter. Imagine getting stranded in a public carpark due to battery failure... Luckily the previous two changes happened at home.

As for the connection issue, I have the battery disconnected twice, but still cannot get the engine check light resolved. After the battery change, I went for an oil service few days later and the mechanic did the disconnection as well on the battery as well. At first, the engine check light did turned off. However, the following day, I have the engine check light on again.

Really puzzling. I do not have this issue prior to battery failure.

three2eight

I got caught offguard for battery failure 3 times. I agree typically you should see weak cranking when starting the car for weak battery. But in my case, all failed without any signs. In fact, the last battery prior to the current one lasted only 6 months...

Jasontan_sg

Remove the battery connector for more then 10 min, because some current are still stay in the car if you reconnect in a very short period. if you test some cable in your car you can see some light go off very slowly, ECU contol almost everything in your car, therefore every signal sent to ECU will stay if there is current.

One more advise, do not jump start your car if your battery is completely flat, this will cause damage to your car, change battery is the best chioce. Do a bit of research on the size you need and which battary shop open after office hours or publice holiday, so you know where to get your battery if needed. Volt meter is still the best choice.

Improper electronics installation will cause drainage in voltage in your battery, like me I fixed too many electronics stuffs in my 8, maybe some cable connect wrongly, i am not sure, so suffer battery in short life spent.

Silver_Z

Why will jump start cause damage to the car?

sqflyer

The ECU has probably logged a permanent fault code. Try hooking up a OBD II scanner to see what error code your ECU is indicating. One of the functions I use my ScanGauge II for is to check if there are any error codes and I can also clear the code if it's a minor fault.

theboy

I had this problem before dude. but after i reset ECU car is drivable like normal. then i got back and checklist my manual. all it was the Fuel cap that is not Close properly! check engine oil cap or Fuel cap! it might not be the battery.

three2eight

Did a refill on petrol yesterday. The light is still on today. Don't think this is the issue. Anyway, the check light was due to flat battery prior...

three2eight

No, did not jump start. I simply replace the whole battery. Not much of electronics other than the usual amps and battery stabilizer. I was told the charging alternator for RX8 is rather weak, hence the shorter battery lifespan. Comments?

three2eight

Hi,

Any idea which workshops might have a scanner to read the error code? Recommendations?

sqflyer

I'm not sure about RX-8s having weak alternators, but my original battery lasted me about 2 years before it showed symptoms of progressive difficulty in cranking the starter motor.

I'm pretty sure any decent workshop will have an OBD II scanner but I recommend getting the ScanGauge II. It functions as a error code scanner, trip computer and digital gauges. Very useful piece of gadget. Go to http://www.scangauge.com/ for more information.

theboy

Did u check your Engine oil cap?

mkl22

try riverview at AMK autopoint level 4. Look for Vincent or Ah Liang. Ah Liang should know my car. Say its a black RX8. They have the full mazda diagnostic kit.

three2eight

You probably wouldn't believe this.... but I got my engine check light solved simply by revving the car hard till redline while on free gear for a short few blips. After that, the engine check light went off the next time I crank up the car! I don't really understand the logic here but heck, the eye sore is gone before my very eyes!

Thanks guys for all your valuable suggestions.

DMRH

Can you get a CEL from a low level on the oil..........???

REgards

spyglass69

Can anyone recommend a reliable brand battery and price ?