I have a '93 fd w/ '99 turbos, Racing Beat exhaust. Engine replaced 50,000 miles ago. Car generally runs great. When cold the idle alternately runs up and down from about 800 to 1200 rpm until warm, then runs smooth, idling at about 900-1000. Anyone have any thoughts about why this is and how to resolve it? Thanks.

 

Tossing this out there for the 3rdgen guru's after pulling it from the wrong board. I'd have no clue since I'm a 1stgen guy.

Mario III

 

It's suppose to, that's characteristic of a rotary engine.

 

Is the airpump installed and working?

 

i have a similar idle prob, but cant for the life of me beleive mazda would intentionally do that ^

 

its the whole swapping the engine thing if i were you take it to a local dyno and have it tuned. my fc had idleing issues when i first swapped the engine for an 89 n/a took it to a dyno and bam now it purs like a kitten. here it cost $50 for light tuning so its not all that expensive.

 

Maybe I should clarify, and maybe not assume so much, but on a cold day all three Ffc's I've had over the years would sputter at that rpm range, and once warmed up would fluttter at 700-900 rpm's. I didn't realize it was and fd so maybe there's a difference there? However, my current fc (88 t2) is pretty steady at ~1100 rpm when cold (on a warmer day) and then drops down when it warms up.

I thought that was characteristic of cold start, if not I apologize. Correct me if I'm wrong, but isn't the idle controlled by the TPS/BAC? I think a leaking intake can also cause idle problems.

 

these engines will sputter in the cold no matter what but when heated up they should stay steady. rough idleing can be caused by bad grounds, tps, egr, bad tuning, light flywheel or clutch, sometimes worn oil, vacuume leak, man so many things. take the time to look over a manual spend a day under your hood, its the best advice i have ever gotten.
good luck

 

I have sold my RX7 after 6 years and a new motor. If I ever get another one, I'll be back.