So finally got my RX7 running that has under 20k miles and has been sitting for a while prior to my ownership. Replaced spark plugs , Pumped out all the old gas , replaced fuel filter , filled it with 5 gallons 93 octane, no start. Replaced the fuel pump with a new unit and it starts no issue - but cold start it idles 2-3k for a little and drops to 15-2000. The other day it Idled warm at 750 , but today it was high, also it sounds a little funny? I’m new to rotary’s . I replaced all the spark plugs before I did any other work, and I know they’re correctly in but it almost sounds like it’s misfiring? Keep in mind the OEM mufflers / Y pipe on it now is shot has holes and is no good. Take a look at the video any opinions or advice appreciated

 

 

Also anyone have an idea what this is? Idle

related ?

 

oooh, haven’t watched the video yet but that’s the silly s4 idle mixture pot. It’s literally just a potentiometer but yours seems pretty messed up. See if there’s any way to turn the screw; L = less fuel (lower idle) R = more (higher idle). If not just don’t bother tbh you’re not really supposed to touch it but mine was shot so I just replaced it with a generic Amazon potentiometer and it’s ugly but works 😂

 

that said, your idle honestly seems pretty normal. The 2-3k is part of the FC’s AWS, or accelerated warm up system. it’s a factory feature that idles the car high till it warms up and it’s controlled by the thermowax, which is a cam on the throttle body that moves with temp. I honestly don’t hear a misfire but I did notice how it dropped and tried to catch itself a couple times. could be worth cleaning your IAC valve or adjusting your idle set screw just to see how it responds. usually you never have to touch the mixture potentiometer in your other pic, but if you can get it to turn maybe mess with that a little. Could also be a TPS calibration issue. The TPS is known to cause a whole host of weird and wacky issues on these cars. All the old potentiometers just kinda get weird over time. There’s a TPS adjustment procedure for the T2 on FC3Spro.com . best of luck, and let me know what you find! <3

 

Thanks I'll get at it tomorrow! Will let you know how it goes. Thinking maybe if I keep letting it run and short drives on my road maybe the old gas that was sitting for years will burn out and it'll idle like new

 

yeah honestly it’s super possible, rotaries can be a little picky with old fuel in my experience. driving and getting that engine lubed up is probably good since she’s been sitting so long too. idle quality is idle quality and it won’t blow up your engine or anything lol. just tune as necessary and you’ll get it dialed. He’ll, my idle isn’t even perfect, it changes between stoplights sometimes and changes with air temp, and I’ve been daily driving my fc for a year. these cars are just old and a little quirky sometimes. get that exhaust leak fixed and you won’t even notice it

 

Hey mate,
Any chance you got this sorted or at least rounded it down?
Having similar "blips" in an otherwise normal idle, and it is running quite rich.

I have a microtech ECU and my car is NA, but the idle is almost identical.

I have started my journey on trying to find a vac leak, but so far nothing has proved this.

 

If you are going to touch this, I believe you need to bridge the initial set coupler.

Good pic of that here:
https://www.rx7club.com/2nd-generati.../#&gid=1&pid=1

 

you’re right, not supposed to touch it other than when setting your initial idle then it is never touched again. And it won’t do anything if set connector isn’t jumpered from memory.
it goes jumper set connector, this is in a different location on jdm and usdm cars. (jap manual says remove fuel cap also for no reason) then adjust bac valve ias if t2 usdm or jdm uses tas (throttle stop on usdm) down to 720rpm. Then you turn the variable resistor (what was pictured) til idle is really smooth, probably adding fuel. Then adjust back down to 720 +30 or -20rpm (according to jap manual). Replace fuel cap. Now you want to get car warm and set tps then remove set coupler bridge wire. Should be good. If not you have other issues.