mckinneyml

I've got a JDM 12AT, fresh rebuild, with Microtech ECU and factory single turbo in my 1980 RX-7. It is running rich and even though I change the oil and filter the oil in the crankcase smells like gas.

At operating tempeture the car smokes at idle. But never smokes cold. I think that the smoke looks white, but my rotary friends say that it is blue and it is burning oil. The car has been using a little oil but it would regularly with a OMP right? I have not noticed any change in coolant level.

Anyways last week I washed the car and noticed that the car was getting gas stains on the body below the fuel door so I replaced the gas cap. I noticed that after I replaced the gas cap the car smokes all of the time, cold or hot, and not just idle, it does it enough to see at slow speeds approximately less than 15 mph.

I assume that replacing the gas cap could increase the fuel pressure in the tank, if my old cap wouldn't seal right. The other odd thing is the car runs significantly better with this new gas cap.

My question is if the turbo's oil seals were leaking and thus the turbo was causing the car to smoke why would the change in fuel pressure make the smoking worse?

Or is the problem in the fuel ratio? Could the car be running so rich that this is soley a tuning issue?

Or is this an engine seal problem?

Note: If I put the old gas cap back on, the car goes back to only smoking when warm and at idle only.

pp13bnos

iTrader: (1)

That is seriously messed up If you have the time, I'd pull some IC piping and see if there is alot of oil in it. Have you had Ralph tune it or anything? CJ

mckinneyml

No I havent had Ralph tune it yet. I'm out of money till next month. I'll see if I can check the IC piping this weekend. If it has oil in it does that mean the turbo is leaking? or that the engine is burning oil?

Rob wants to pull off the turbo and see if the engine burns oil without it, but I don't have money to rebuild the turbo now. I hope it's not the turbo. I don't think it is because why would a change in fuel pressure cause the turbo smoke more? Also the turbo wouldn't have anything to do with the oil smelling like gas would it?

mckinneyml

I checked the IC pipe connected to the turbo going to the IC, the easiest one to remove, and it was dry, no signs of oil.

Also I put the new gas cap on, removed the oil cap, and took it for a half hour drive. It is cool out today not as hot as it has been but there was no smoke so far. I will take it out again later tonight.

Could the crankcase not be prperly vented?

pp13bnos

iTrader: (1)

I understand about being out of money.

Its very possiable. Is it even vented at all? CJ

mckinneyml

Below the oil cap on the filler neck there is a rubber hose that connects from the filler neck to a hard line. The hard line goes accross the top of the engine under the water pump and turns down the side of the engine and runs over the top of the turbo. I can't see what it connects to because the heat sheild is in the way.

pp13bnos

iTrader: (1)

Is this routed into the exhaust? Try taking a peak at it. While, I don't know of anyone routing a vent this way, it could be possiable....I guess. CJ

On a peripheral motor I ran with a large shot of nitrous, I had to drill a tiny little hole in the oil filler cap. Just a realy small one, othewise, it would blow oil all over the rear rotor, at high rpms+nitrous. (It would come out the little tube, othewise.)

680RWHP12A

sounds like improper crancase ventalation.. easiest fix, drill a hole in the oil fill cap.. cost=free

sounds like a fun setup you have there, enjoy!

mckinneyml

I took it out last night. Drove it for approximately 2 hours and I couldn't get it to smoke without the oil cap. I hope this fixes it.

Thanks CJ and 680RWHP12A. Now I can focus on getting it tuned.

pp13bnos

iTrader: (1)

I would'nt make it a habbit of driving without a filler cap on it. CJ