Hey team,

Currently having an issue with my car idle spatially.

Car specs and Mods

RX8 - S1 - 2005 - MT - Bridge port. - Cold air intake - De-cat

Problem

The car Idles fine from the start-up until it gets to running temp; once it gets to temp, idle starts to fluctuate.
It happened two weeks after the rebuild. and it can never find idle.

Please see the video.


Troubleshooting,

Brand New Spark plugs,
New spark leads.
Reset ECU and NVRAM
Cleaned throttle body
Cleaned MAF sensor
Ensured all clamps were tight and no air leaks.
No DTC codes
Reset ECU map back to factory default (have mazdaEdit)
Reset RPM to 1650 idle.

I think it could be a vacuum problem some were? or bad coils?


Just checking if anyone has any ideas on where I should look next

Cheers

 

Most people will replace coils plugs and wires all together so it could totally be that.
I do not see in your list of trouble shooting resetting the ESS ? quickly hitting brake pedal 20 times after turning key to start position ? Or is that what you meant by resetting the rpm because I know of no procedure to do that other than through software ?

 

A bridgeport will require a tune to idle properly most of the time.

The fuel trims should help it idle better after a while... but every time you reset it it goes back to stock and will need to relearn again

What are the fuel trims like? If they are high the ECU might not be able to compensate so thats when the tune will be needed

Stock timing strategies will likely not allow the bridgeport to idle properly either.

A bump in idle speed like you tried will likely help... but the timing at that RPM isn't the best for smooth idle

The clutch switch can also make it idle like that. Does it idle better in Neutral?

 

Hey ya, yes have also done the ESS as well, also disconnected batteries for 15 min.

 

Hey Mate,

thanks for your reply, Yes it dose,

If the engine is cool, it idles just fine no issues, as soon as it gets hot it rolls like in the video.

if I turn off the car when its hot and turn it back on, it idles fine until I touch the gas peddle and rev the car, it then gos back to a rolling idle.

 

Did you find the issue? My engine is doing close to the same thing with streetport. It will idle like a bridgeport between 50-1000rpm and then after about 10-15seconds will start idling normal at 900rpm. If i blip the throttle the rpm's go up and then down really low and then go up and down and sometimes the engine will turn off as the idle is too low. I searched the forums and another guy had the same issue and it turned out to be a fuel injector. I don't know how you would diagnose that. My engine was rebuilt 3 days ago by mysleft- i have rebuilt many rotary engines before- compression is 100 both front and rear, new coils, spark plugs and wires, cleaned air mass sensor, checked for vacuum leaks. Car has Racing Beat header and cat back exhaust, ram air filter, rev 3 engine flash. Doesn't change with clutch in or our. Seems to happen when engine is warm and not cold. Normally if a car has a lean idle it will fluctuate like that so maybe one of the primary fuel injectors is bad? Maybe i just need to drive it more for it to learn the fuel trims?? How long does it take to learn fuel trims?