i just bought another fc after my first one got hit and im having issues diagnosing the issues im having with it. its a 1986 rx7 and its not the original motor from what ive been told and i was also told it only has a vacuum leak. i want to make sure that it doesnt need a rebuild. it starts easily but when im warming it up it smokes a whole bunch but goes away when its completely warmed up. it drives good except the idle drops when i come to a stop and it bounces a little. not much but it still bounces. and it seems sluggish to me but then again my first fc wasnt stock so im not used to having a stock fc. can anyone give me some things that can be wrong with it?
thanks in advance too.

 

The cold start smoke is most likely worn oil control rings. It could also be leaking injectors but that usually causes hard cold starts. Smelling the exhaust during warm up will give you a better idea. Bouncing idle can be a TPS out of adjustment and/or a dirty BAC valve. You can download the FSM and other rotary related literature from the following link.

http://foxed.ca/foxed/index.php?page=rx7manual

 

Does your dropping, bouncy idle occur constantly in the situation you described or does it do it just while warming up an then decides to behave itself once fully warmed up or all the time when the situation presents itself warmed up or not?

 

thanks ill look it up. i adjusted the tps and i got it to where it wont bounce as much but when i come to a stop it will still drop low then come back up and stay stable for a little bit now. i asked my friend that i bought it from and he said it most likely have a small vacuum leak around the intake manifold also the car has no cat and the air pump isnt connected to the exhaust either. (these are new things to me cause my old fc was carb. and didnt have any electronic stuff to it cause the person i bought it from cut the harness). i will be happy if the idle was alot more stable but ill look at the link and see if anything on it can help me out. thank you

 

@satch
it does bounce when ever i come to a stop i had adjusted the tps and it made it more stable and it will stay still for a small amount of time but if i stay in one spot for too long it will bounce a little more. funny thing i noticed is that when its not completely warmed up it doesnt bounce. it will rev up and down when i first start it but when it gets a tiny bit warm its like normal but when it warms up completely it starts to bounce again. (i just noticed it when i drove it at 1am and the tempeture was about 50s-60s outside)

 

i have an 86, mine smokes lol. its sluggish as well. lol but i think pretty much the 86's have some kinda problem. it was the first year of the fc, they still had bugs to work out. but that's just my opinion. not that its needed lol. at least yours is running at the moment lol good luck to you man

 

im having a similar problem.
the leading coil is not firing the plugs and trhey are brand new plugs and wires, and the voltage to the coil is correct.

 

ill try the leading coils as soon as i get all my spare parts from my uncles house. but i also noticed that it smokes when i decelerate from high rpms when i stay in gear. if i shift up or press in the clutch it wont smoke. i just got the car so im noticing new things from time to time. accelerating high rpms=no smoke, decelerate from high rpm in while in gear =spy smoke screen XD

 

@ nevertolow yeah well i think that mine feels sluggish to me cause ive only driven my old rx7 which wasnt stock. lol i was told by the guy i bought my first 7 from that it had the true "puerto rican" tune. lol it had nothing but the motor, the cooling and the ignition system in the engine bay and it had a racing beat intake manifold, and a holley 640 four barrel on it and a straight piped exhaust (it backfired flames too big and sounded like a shotgun too) and probably got about 8 miles to the gallon XD. i barely knew how that worked cause it didnt even have the wiring harness on the car so it was wierd and i just learned how to keep it in shape. nothing too technical. it was my daily until someone tried to beat the train and tboned my on the driver side.

 

hahahha yea. thats probably a reason you think its sluggish hahah. sry to hear bout the other rx man. oh and btw all the chickys love flames hahaha

 

yeah they do. one of my friends, she said she like the smell of the exhaust cause it got her light headed from all the gas. she misses the car more than i do. i got my motor and everything from my last car but im trying to save it to fix up while im driving this but i want to find out what is wrong with the car im driving now before i take its motor out. i just hope its not blown and that its something small ill be able to change the plug wires tomorrow to see if that could be the idle issue. but the smoke still has me wondering.

 

every one says seafoam, bs. dump some marvel mistery oil in the engine and let it sit a day or two , right down the plug holes and roll it by hand, a few ounces will do . 24 to 48 hours.

spin it out with plugs out, start and run. drive it hard with some long duration decel pulls followed my a hard full throttle pull. the engine is suffering from carbon lock on the oil seals from lack of oil changes. put some MM in the fuel tank as well and run it hard for a bit, it might clear up. it has worked for me in the past. best of luck.


joe

 

where can i get this marvel mystery oil? ive never heard of it. and if i get it i have to put a couple of ounces inside of spark plug holes and turn the motor by hand and also put it in the fuel? and thats it? ill look it up and try to find some but ive been to alot of auto part here in town and ive never really heard of that but ill check again. sorry for the confusing typing its late lol

 

thanks for the mm oil tip ill go look for some in the morning. i looks its worth a try. should i pour some in the oil like the official website said also?

 

its a red bottle that looks kinda like one of those BS fuel injector cleaner bottles, and the label is black.
walmart
checker/ schucks/ craigen
pep boys
autozone
advanced auto ect.

 

yeah so i havent been on lately...... been busy but the car still has some issues. the cold start smoke stopped and the only time it smoke a tiny bit at cold start is when i start it up early in the morning when its all moist and cold outside. but it still smokes on long decel from high rpms. and i put a new alternator on it and it barely bounce when everything is turned off but when i turn on the lights step on the brakes and put it in reverse it idles really low from when it would with it off. i had to turn up the idle so it wouldnt cut off when i turn on the lights and stuff. so now the only issue i have now is the bouncing/low idle when everything is turned on and the smoke when its decelerating from high rpms. (which i think just might be carbon build up) any more tips...... and i havent tried using the mm oil yet but will next paycheck..(in college and bugdet a whole bunch XD

 

MM Oil is basically just a liquid wax. Seafoam will clean carbon buildup, raise compression, clean the injectors, etc. However, ignore the instructions on the can, just dump it in the gas tank and go for a drive.

Sometimes people get into trouble if they try to get fancy with the application of Seafoam, usually when sucking it in through a vacuum line. Trust me, just dump it in the tank and enjoy the benefits.



.

 

yeah i used to do that with my old fc lol just throw it in the gas but now i believe that its more of an electrical issue and its burning oil instead of gettin rid of the carbon. its pours too much oil in the motor at high rpms i think. never smokes until decels from above 5k rpm. but i think the idle issue is an electrical problem now for sure cause when everything is off it runs perfect and only moves about 25-50rpm when i idling but when i turn things on it starts to bounce more and also idles alot lower. im gonna get some mm oil as soon as i get my next check and use that. but thanks for all the help and ill still try to keep this updated so i have more ideas of what it is. im also gonna go to mazda and see if any codes come up( because no one else in this town has a scanner)

 

No need to go to the dealer as it will likely be a waste of time and or money.

http://www.teamfc3s.org/info/article...odes/main.html

 

Lots of smoke when decellerating from high rpms = blown oil control rings.

Two options:

1. Rebuild the motor and replace the oil control rings.

2. Replace one quard of oil with Lucas Heavy Duty Oil Stabilizer. I got by for over 20k miles doing this. Motor was so bad, I shut down an entire freeway due to the smoke screen. Cars had to stop in the middle of the freeway because they couldn't see a damned thing. After the Lucas, it would only smoke after redline+ deceleration during autocrosses. Worth a shot if you can't afford a rebuild right now.

 

ill get that on thursday and try it out. i cant afford a rebuild now but i do have another motor from my old one but im not going back the carburated set up if i swap them out. cant afford the 6-8 mpg and i dont really have a way to get to work and school if i dont have the car running . i dont reall want to swap the motor aslo because the other one has been sitting since last spring break. i dont know if the motor will still be good after sitting for that long. its been covered and on a kart outside but under an awning with oil and everything still in it. (was told that should keep it good from an old puerto rican rotary head lol)

 

thanks for the homemade scanner lol. you just saved me an arm and a leg.

 

i tried the lucas in the oil and i havent reved it up and let it decel yet but when it starts up cold it also starts up normally and about 10seconds after i started it it starts to pulsate but goes away once its warm. i think its just in need of a tps adjustment but what else could it be? you think the timing could be a little to far advanced?

 

What is your idle at. Normally it should read 750 fully warmed up but maybe a little higher will help your problem. Also, your BAC might be giving you some issues. If the idle is jumping just pull the plug off of it and see what happens. The BAC will at times clog up internally and then are in need of some carb cleaner being shot into the internals after it is removed from its mounting position. If you observe which of the two BAC terminals receives power and which does not you could hot wire it to the battery to help check and or unstick the device. Just be careful to not cross the wires or hit one terminal with both wires at the same time. The BAC will click each time it receives a ground and a voltage signal on the proper terminals. Just touch them briefly as opposed to holding both wires to the terminals for a period of time.

 

its idling at 900 but i made it that high cause if i turn on my lights and depress the brakes or turn my fan blower on it will lower to about the fat line close to the bottom of the tach. which is 500 rpm i believe and it makes my voltage drop low like just above 12volts