RX7CMS

Bill says my 1st gen smells like a lawn mower, 12A stock manifold no cats a RB cat back

Apex13B

my car runs so rich at idle, it smells bad with FULL emissions equipment



looks like you might need a rebuild soon

ROTARYROCKET7

hold up so if you get the RB headers u dont need the cat replacement pipe just the presilencer?. I thought it was the RB header to RB CatPipe To RB Presilencer to RB catback?. But i dont think it will spit out flames unless u push it passed like 6000RPM. Let me know ok



Jazerx7, nyc

1Revvin7

rip that sucker apart and bridgeport it!!!

Baldy

would that cause a big puff of smoke?



I haven't seen it smoke on startup, or when cold, or during normal driving. Only when I would push it high, then let off gas while keeping clutch engaged. Does backfiring and flame-throwing leave a big puff of smoke?

RX7Aggie

mine smells like crap. i have no cats, downpipe, on cat-back. seriously, everytime in come in from driving my car, people say "you smell like gas". i dont mind it, unless girls are with me in the car, then i feel kind of bad for them. but then i think to myself "i like girls, and i like the smell of my car, why not mix the two together?"



that's rotaries for you, get used to it. i'm sure mine's rich, and it drinks gas like crazy.

Baldy

also, it never smoked before I did the exhaust mods



and it doesn't smell I was just wondering if it should

pengaru

well since you seem to only have smoke on deceleration / lugging motor off throttle... it would either be oil getting in past the oil control rings or fuel... the cat(s) will do a decent job of supressing this smoke normally, unless it gets excessive.



i'm not sure if the FC in stock form does fuel cut on deceleration, maybe someone else can answer that... if it doesnt it might just be unburned fuel causing the smoke.



my guess is oil control rings though, they will often cause a small puff of smoke when shifting and smoke on deceleration when they start going bad.

pengaru

damnit i tried to edit my previous post but ran out of time while adding more, here's some more maybe it will be of help:



I think what happens on deceleration with bad oil control rings is your throttle is closed, but the rpm's are still kept high due to being driven by the movement of the car (clutch engaged), so there is a large amount of vacuum in the engine/intake manifolds during this period... this can suck oil from the rotors passed the oil control rings, or it can also help leaky injectors leak by 'sucking' the fuel out of them, though that is less likely since the FPR should be maintaining the pressure difference as a constant even under periods of heavy vacuum....



I don't remember if you removed the pcv stuff/rats nest, there is a mechanism that is supposed to use vacuum to help suck out crankcase gases, it might also help prevent this smoking on deceleration when working properly... since it too should have greater vacuum when the manifolds do, which should help keep the pressure differential between the 'crank case' and the intake manifolds (the intake part of the combustion chamber is basically part of that during the intake period).. you might want to check that out and make sure it's pressent, conected, and working properly.. I'm not sure how significant this is to prevent smoking but it seems plausible. When people remove the rats nest and pcv with it, sometimes they cap the nipples on the filler tube and intermediate housing to find their car smokes all of the time, this is because they are not letting the 'crank case' vent pressure increases caused by blow-by, so then oil is getting forced passed the oil control rings and now theres shitloads of smoke. Your situation sounds similar but it's only on deceleration, which is a period of high vacuum... the pressure difference caused by that is similar to the situation with the capped nipples, so you might be able to find your solution on this route.



just some ideas...



oh btw, a piston head friend mentioned to me once before some product that was used to increase the vacuum applied to the crankcase on piston motors that supposedly improved a number of things... trying to search for this might be a help, maybe it can be used on a rotary to help reduce smoking. Though more vacuum will likely suck in more junk too for your oil to mix with, like gas.. especially if the injectors leak.

Baldy

Thanks for the info. I did leave my emissions stuff on.

Here's the update:



I had my wife drive my car while I followed behind. I told her to accelerate past 5k rpm, then let off that gas, which she did in 2nd and 3rd gear. I dumped so much smoke that I could hardly see the car. She just let the car deccelerate with the clutch engaged, and it smoked the entire time is was decelerating, albeit a little less with declining speed. It was very thick grey smoke.



Can the oil control rings go bad really quickly? Because like I said before, I never noticed smoke until yesterday, and now it leaves a lingering cloud (when throttle released, clutch engaged).