so I have an 87 TII with a brand new rotay resurrection rebuild, and a brand new BNR stage 4 turbo.

my exhaust smokes A LOT. As in i can easily fill my front yard/street with fog at idle.

No, my coolant seals are not blown. The smoke smells like burning oil and there are no bubbles in the coolant.

There was oil just dripping out of my wastegate, and I was sure this new turbo was ruined somehow. There was also NO oil before the turbo when I removed the exhaust manifold to check it. I heard that I may need to get a restrictor pill for the BNR turbo, so I called up Bryan and he mailed me one (for free, what a guy).

Today I put it in and the smoke goes down to almost nothing. ALMOST, it would still smoke noticeably, but NOTHING like it used to. the wastegate is now clear of oil. I take it around my neighborhood and get about 5 miles of easy driving to make sure nothing is lighting on fire and nothing does.

so I decide to make sure the turbo is ok with a little boost. I give her about 3/4 throttle up to 4k rpm, and build a good 5psi, then hit a massive wall. This wall is familiar to me, and I'm almost positive its just a boost leak, and it wasn't as violent as fuel cut.

HOWEVER, the smoke is now back in full force. WTF??

it's dark and rainy outside but tomorrow I will take a look at the wastegate and make sure the oil is not collecting there again. What could I have broken to cause this smoke to return?? could the restrictor pill have become dislodged somehow? I couldn't even get it to fit in the hardline so I just stuck it in where the hardline attaches to itself and tightened it down. Are the turbo's oil control rings the culprit? GIVE ME YOUR IDEAS

I also apologize for this long post.

CLIFF NOTES:
my exhaust is burning oil and making tons of smoke. The engine and turbo are freshly rebuilt. the smoke went away after installing a restrictor pill. I hit about 5psi of boost at 4k rpm and now its back with a vengeance.

the tail end of this thread contains pics of BEFORE
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/omg-my-car-runs-11-a-794600/

 

yo,

I have the same problem. I figured the problem out, I premixed TOO much oil w/ my gas, thats why itwas burning soo much oil..I blocked off my OMP and do premix 2stroke oil. Do you premix?

 

Do you have catalytic converters? If so, before you condemn any other source of oil consumption such as oil control rings/seals or turbo seals, consider that a cat will collect and hold oil from the engine until the oil finally burns out, sometimes it takes several days for it all to burn away. Wait a while and see if it diminishes before suspecting the worst.

 

actualy i dont think its premix, probaly ur turbo seals are bad..

 

no I don't premix, and no I don't have any cats.

if either of these were the problem, then why would the smoke dissipate and the return? also before there would be almost no smoke on start up, and once the exhaust warmed up a little it would start to smoke. now it starts smoking immediately.

 

Did you ask Kevin for his opinion?

 

actually, I really wanted aaron cake's input on this particular problem if he's available.

 

Your turbo is need of some help.

Pull a coupler off the intercooler, and check for oil in there, if you see any oil, the seals are gone/leaking, if you don't see any oil, then the seals are gone on the exhaust side..its simple stuff.

PS: wastegate restrictors are free from any Turbo Dodge 85 to 90 at the junkyard, add more than 1 for more boost quicker/less RPMS.

 

do you have the stock PCV valve system? How is your crankcase ventilated?

 

It's certainly possible that running it without the restrictor damaged the seals, although it is unlikely unless you have a seriously pressurized oil pan (ie. lots of blowby). Easiest way of course is to check the intercooler pipes and/or remove the turbo.

 

well I called Bryan at BNR and he said that not having a restrictor should not have damaged the seals, and that I should just drive it to get the EGT's high enough to burn off all the extra crap in my exhaust.

I also checked on my PCV, which is perfectly fine, I can blow through the vac line easily. I have both of the PCV openings tee'd together and then routed through the stock hard line that goes to the TID.

soooo, i went on the interstate and drove 100 miles tonight, and almost all the smoke is gone.

HOWEVER, now I am having a very weird problem where the amount of smoke fluctuates for no apparent reason. I literally sit and watch the car idle and there will be NO smoke. then I keep watching it and then suddenly smoke will come billowing out of the exhaust. keep watching and then it will go away again.

what could possibly cause that?

 

Pull the turbo inlet duct off and look for a saturated duct.

 

Never mind me. I see you already did that in your first post.

Seems to me if you remove your oil filler cap and leave it off, that would eliminate there being any crankcase pressure buildup. So if it still smokes after you remove the cap, then you've eliminated one possibility.

 

Pull the intercooler off the car runs about 1 gal of gas through allow to dry and see if the smoking stops.

I think you are just moving oil inside the intercooler from the stagnat flow areas of the cooler, allowing for intermitten smoke clouds.

 

Let me just clear this up a bit, because there seems to be some confusion...

The exhaust is not smoking.


That is all.

 

ok, so I went and did some work on her today. I pulled the intercooler and ran some gas through it to try and clean any remaining oil out of it. There was significantly less oil in the pipe then there was before I got the restrictor, so that seemed like a good sign.

I also pulled the UIM off to check my ECU ground and that seemed oil free, and just kinda smelled like gas and oil, but there was no standing fluid.

After that I went for a short drive, and the smoke came back again once the car was warmed up. I pulled the intake off and there was warm fresh oil in there, so that pretty much removes any doubts for me that there is a leak in this turbo. Unless the PCV is belching oil into the intake where else could all that oil come from?

so I suppose it's time to pull my turbo again. If that doesn't fix this then I'll probably have to sell the car... le sigh.

 

pull your dipstick and smell the oil, if it smells like gas, change the oil. I had this problem on my pickup after I put the ITBs on, it smoked like a chimney. The extra gas had thinned the oil and was just leaking into combustion. Once I change dthe oil I was golden, no smoke.

 

Just drive it smoking, its only getting extra oil in the engine from the leaking seals on the pressure side.

Leave your dipstick open to vent to atmoshere., in other words. Just allow to sit loose do not push it down tight, see if this stops the smoking problem. Maybe the PCV valve is shot, did you clean it out with carb cleaner? The PCV? They often make a crazy smoke show, when dirty or bad.

How about the plugs, clean the plugs, change oil, reflush all piping and intercooler.

I seem to recall when I blew one engine and reused the cooler. It took me 6 months to get all residue oil out of the cooler, because I didn't flush it good.

only smoked when it got hot enough..

 

how do you know this isn't a tuning issue?

 

To prove it's not the Purge valve, just pull the hose off it that goes to the bottom of the filler neck. Then the Purge valve can't be a player.

Then also pull the silver colored check valve out of the turbo inlet duct, and let it hang in mid air/wherever, and plug that hole in the duct with a common bolt/whatever.

Then there's no way the Purge valve nor the line from the filler neck to the turbo inlet duct can be players. No way. If it still smokes, to me, it has to be the turbo seals on the front of the turbo.

IF you have an original OMP and the lever is STUCK to the full up positon, that can cause smoking at idle if you idle long enough.

 

ok, the OMP is not stuck open, so at least thats good.

I took the intake off and wiped it down with paper towels and ran a little gasoline through there to get most of the oil out of it. I also checked the dipstick and it didn't smell like gas to me, and actually looked quite clean.

I changed the spark plugs as well. The old ones were covered in oil and all black.

I plugged the hole in the TID and took off the silver thing and just taped a bit of paper towel to it so I could see if any oil would come out. I also pulled the line off the filler neck and did the same.

while it was idling it SEEMED that i could control the smoke with the PCV and i was almost sold. Then I drove around my neighborhood for like half an hour and it was smoking more. there was no oil on any of the paper towels i taped to the various PCV openings.

I'm going to try and just run it on the interstate again tonight and see if it just needs more time to burn off oil stuck in odd places. If it doesn't quit after that then it must be the turbo.

 

I'd pull the LARGE hose off the bottom of the Purge valve altogether. That way there's no way oil could get into the throttle body/intake from that angle. Maybe even just remove the oil filler cap and put it on the shelf. Then go for the ride.

I don't remember ever removing that cap and driving, but I doubt any oil is going to slop out that pipe. Do that and there's no way the purge system could be the problem. I mean the crankcase would be fully vented to atmosphere and therefore no backpressure anywhere. Unless I'm missing something.

One more original thought here. Maybe the blow off valve (not the Mazda name, I forget right now what they call it) is the problem????? Do you hear the afm's vane clanking shut after letting off the throttle. Listen for that the next time you do a small bit of boosting. But then that wouldn't explain the smoke at idle coming and going.

But, heck. You already removed the checkvalve and hose from the turbo inlet duct, so there's no way for oil from the Purge valve to get in that duct and on to the intercooler.

EDIT: Air Bypass Valve= BOV

 

What thickness oil are you running? drain it, fill with 5w20 see if your problem goes away. make 100% certain your oil return is angled correctly. throw your pcv system away and install a catch can.

 

i'm running the recommended 10w40 oil.

and i don't have the stock rats nest so my PCV WAS venting straight into the intake, and only the intake. NOW it vents directly to the atmosphere at both the filler neck and from the center iron.

I have never heard the afm clanking around, and I'm getting a new BOV to replace the stock bypass valve and a new intake pipe. I doubt that will help, but it couldn't hurt.

 

perhaps ur motor is still breaking in like mine. It was moking like insane, until 3hours later of idling the smoke vanished...It could be assembly lub driping into the intake, into ur engine making it smoke...