I just purchased a 94 FD. The car runs great under driving conditions but when the vehicle idles it has a slight miss or skip. This only happens at idle and is erratic. Sometimes it idles really smooth and then all of the sudden will skip just a little. The plugs were supposedly changed a year ago. Any ideas what could be the issue. Any help appreciated. Thanks AJ

 

Well rotaries normally skip and misfire when they are cold, and sometimes do so when warmed up.

How many miles are on the car? How high is your idle and how many times (can you guess) it skips a minute?
I had to adjust my throttle plates to factory spec to stop alot of my misfires. So that's another option, but it take a while.

 

Mine does that all the time. From what I'm told it's normal.

Dave

 

My FD only has 63K original miles. The car is completely stock. When I bought it had a Greddy intake on it and some cheap-o down pipe but everything else is stock.

 

hmm, should be normal then. My motor has 37k on it. Like I said check the spacing and adjustments for your throttle plates. Also try adjusting your timing to stock. I'm not sure what it is for the FD. Timing might be fine, but it never hurts to check.

 

it's not really normal, although many cars do that.

have the primary injectors cleaned/inspected.

also might be tps, small vac leak or map sensor

 

Its Normal For It To Misfire While Its Cold. Always Let It Warm Up Before You Drive It. I Would Suggest Changing The Plugs And Wires. Thats What I Did And It Stoped. Rotory Motors Burn Rich So The Plugs Need To Be Changed More Often Than Piston Motors. If They Were Changed A Year Ago Its Time To Change The Plugs

 

I don't think the injectors have much to do with it because I had mine flow tested and cleaned once and the popping sound didn't change at all.

It's definitely just something I get when the engine is warming up. If you get it when everything's nice and warm I'd look into it further.

 

Yeah it doesnt feel like a fuel injector issue. It feels more like a miss fire. It does it after the engine is warmed up. It is very sporatic though it only does it sometimes. I will have the car on my dyno possibly friday just so that I can check the AFRs and make sure that im not leaning out and going to blow something up.

 

Mine does it too. All three of them have.

 

Mine does it too. mines an 87 fc tho but the motr is newer its not the orginal one. i actualy like it sounds like its cammed in some ways haha! as far as ive ever seen in person or video or anything most rx7s do that.

 

I have the same problem with my FC, she misfires when she's cold. My FD didn't do it, but she had all kinds of other issues.

 

Still, the fact that it's a common problem doesn't make it right. Properly running engines should not misfire, period. I'd like to know what causes this- someone has to know, as common as this apparently is. Fuel? Timing? Why is it that the factory base map, after a certain period of time, no longer works?

 

i think we need the opinion of someone who actually bought a second gen brand new... in the 80s!

 

i'd like to know as well, my car misfires even when it is warm...

 

i would say it could be the throttle position sensor but i am not by any means positive since it only does it when its warming up or idling.

 

i purchased a new 88 in 88 it is an s4 ragtop, manufactured 12/87.

i do recall it having an occasional day even when new with a little snap crackle and pop.

but the idle has never been adjusted and it is still right at 750 rpms now.

just this week i've noticed a little 'stumbling' at idle, even when very very warm, but no real misfiring.

my approach in the past with this (every 4 years or so) was to run a can of fuel system/injector cleaner (bg 44k) with one tank of gas...

then 1-2 additional tanks of regla, then change the oil and check the plugs, replace if needed.

this has always smoothed things out again for a few years.

the cleaner is in the gas now, we'll see how she runs next week and after the new plugs/wires too.

henry

 

Ftw^