Suparslinc

I think I have the carb set to specs as far as the mixture and idle go, but I have some really weird problems.
First of all, I have a huge cloud of smoke on decelleration.
On the hiway, I will run it up to 7k in 3rd, then let off the gas with car still in gear. About 5 seconds later, I see this greyish cloud of heavy smoke in my rearview mirror. I mean I am surprised people behind me don't wreck from the blindness. I think it is unburnt fuel but I'm afraid it might be a sign of a seal letting go. And when it happens, I notice a strong gas odor in the cab. I get the same smell when I push it hard alot at low engine speeds, then starting is a chore.
I lose a fair amount of oil but I also have a pretty good oil leak at the coiler (fixing that soon) so I can't be sure if it's buring or just leaking.
And the car is hard to start when cold, I think my plugs are fouled so I'm replacing them tomorrow along with an oil change.
So I'm getting bad gas mileage, I smell gas when I run it too hard, and I see what I suspect I hope is gas when I let off the throttle. What should I do?

oni-dori

hard starts shouldnt be a problem if you are running rich. its something else if you have a hard time starting. try a good tuneup if you havent done it recently. and greyish/white smoke is coolant leak, so maybe your seals are breaking up after all. hope they arent though...

FD Racer

what does the smoke smell like? Sweet or oily?

bizarro

iTrader: (1)

I agree with Oni-Dori...greyish smoke would be coolant...if you were running rich it would be black smoke. An easy test to see if you have a coolant leak is check your coolant level...if it topped off, then turn on the engine with the cap off and watch for bubbles...

Suparslinc

Damn my greatest fear spoken out loud.
I have been losing about half an overflow tank per month. . .
I think I'm losing fuel and oil it smells sweet, then oily after sitting.

bizarro

iTrader: (1)

If you are losing fuel then you may have a rusted fuel tank...test for this would be to fill your tank, place a cardboard underneath your tank before you park her for the night. Come the next morning, if you see spots on the cardboard you have a rusted fuel tank. Also, check your lines leading upto your fuel filter and fuelpump for leaks.

Losing oil would not smell sweet coolant does...so...you may have a coolant leak but when you shut her off then the oil leak from your cooler maybe taking over the smell...

do searches and you'll see...good luck...

Suparslinc

Isn't there some kind of rule for smoke color? Like white smoke=coolant
grey=fuel
black=oil?
I know the gas tank isn't leaking, I just think I'm losing alot of unburnt fuel through the engine and out the exhaust. I'm pretty sure I have a mild coolant leak also. But since there is nothing I can do about that, I'm focusing on what the grey/white smoke is that comes out when I let off the throttle

Northern 7

iTrader: (3)

Oil smoke is usually bluish gray - and from what you are describing, it sounds like oil to me. I think your original post hit it on the head - bad o-rings.
does it smoke on start up? does it smoke between shifts, especially high RPM shifts?
I don't think it's unburnt fuel - that would explode in the form of a back fire. And black smoke is usually a sign of running rich - I have never seen a car run so rich as to be blowing huge clouds of smoke out the exhaust. A rich condition will usually show at idle during warm up as this is when the car is supposed to run rich.

oni-dori

at this rate, you may as well rebuild the motor.

Suparslinc

It smokes the most when I take it slowly up to redline in 1st gear, then let off the gas. It will smoke like crazy on decelleration. I can't quite pinpoint the smell though. I should take a picture of the smoke and let you guys decide what it is.

Sterling

Superslinc, I think you may just need a new intake manifold gasket set is all.

Aviator 902S

If in doubt, check your spark plugs. Ones that are:

Dry and either tan or grey color = ok.

Wet and oily = bad o-rings (the ones on the sides of the rotors, not the coolant o-rings). This would require a rebuild, but your rotors and housings should still be ok so a basic rebuild kit would about do it.

Wet and smelling like fuel = LOTS of unburned fuel. If only happening on one rotor you're either not getting spark to that side of the engine (which would also cause low power and very rough running), or you've lost an apex seal (which would kill compression in that housing, causing the fuel to not ignite. The seal will have destroyed the rotor and housing as it was uncerimoniously ejected out the exhaust port).

Wet, and/or shiny clean and white, and smelling sweet like coolant = leaking coolant o-rings. This will be accompanied by white smoke most if not all of the time, hard starting, and dropping coolant levels. Engine temps may also be higher than normal. May have been caused by broken lands around the seal grooves, but more likely due to engine being overheated some time ago, which warps the rotor housings and ultimately causes the seals to leak. Rebuild and replace housings.

Suparslinc

Here are my plugs from today, these ran about 15k miles or more though I usually replace at 9. The two on the left are leading. What do you make of these? The leading seemed dirtier than usual so I think it might be an oil ring or just from not being changed in so long.

Suparslinc

The oil around the washers is probably from the oil cooler thanks

Aviator 902S

Those plugs look ok. They don't even appear to be worn judging from the photo. (When the center electrode appears to be somewhat square in shape rather than perfectly round it's time to replace them). And the trailing plugs are recessed in the housing (looking at them from the inside if the engine) so it stands to reason that they'd be cleaner than the leading plugs.

If you are leaking coolant it's not yet enough to get your plugs wet, and leaking oil from the o-rings would foul them up in a very short period of time, ie: < 1000 miles.

Could still be burning too rich though. You said your fuel economy wasn't good but rotaries aren't that great anyway when it comes to fuel economy. How's your fuel economy compared to normal? BTW, that gas smell is something I'd be concerned about considering the risk of a fire...

Suparslinc

Thanks for your replies everybody. I've decided it is a coolant leak, either from the block on manifold. It could be the coolant seals because this is a used motor and I experienced similar problems when I installed and tuned it. On the other hand it could be the o-rings because I've never replaced them, and the irratic occurance could have to do with vacuum (maybe? I dunno).
Regardless, I plan to rebuild the intake manifold this winter and do a shutter valve removal and ACT block-off plate to see if this solves the problem.
And thank you, for your support