Murph

So last Monday I bought a 1990 Mazda Miata. It had a Greddy turbo kit on it, and it all works great. Yesterday I was driving down the freeway in 5th gear at about 80MPH when I saw white smoke coming from under the hood. I got off the freeway and stopped in a parking lot, I looked under the hood to find an oil hose had slipped and sprayed the turbo and what not with oil.. I put the hose back on and got a metal clamp so it wont happen again.

Here is the hose that slipped

oil.jpg?t=1345684849

Now I figured it wouldn't be a big deal but when I started the car again smoke flows out of the tail pipe and the turbo and the engine was running bad, shake a lot and sputter when I let off the gas. This morning I went out after letting everything cool off all night and all the lines are good and not leaking anywhere. I started it up and the engine runs normal now, normal pressure and revs. But still getting smoke out the tail pipe and the turbo.

NOW! Before you all blow your loads. I did do my home work and looked up the problem. I found a lot of people saying it can be three things; a bad seal, clogged drain, or too much oil pressure.

So my question is, wither its one of those things or if it is possible that some oil got sprayed into the turbo some how and is now just burning off.

Thanks,
Murph

Savington

iTrader: (31)

Where does that black line run to? Do you have it hooked into the intercooler charge piping, by chance?

Murph

That line, and the small blue one under it that runs from the intake into the turbo both run into a little silver box on the other side of the engine where there is a line at the bottom of that box that drains into the oil pan.

Leafy

iTrader: (1)

Sounds like you built up some massive crank case pressure and blew off the crank case vent line. I would bet that whatever caused that much crank case pressure to build up is whats causing your oil to exit through the exhaust.

TorqueZombie

iTrader: (6)

Have any pics of the rest of the engine bay?

Murph

The silver box is just below where the strut bar bolts in on the left side.

Braineack

iTrader: (62)

connect the black hose directly to where the blue hose is going on the intake and try again.


but it's probable that your PCV is letting boost through.

Murph

Do I need to put something where the black hose is coming from?

Also. Im a total newb with forced inductions. Never work with a turbo before.

Braineack

iTrader: (62)

Valve cover to intake. bypass the catch can.

Murph

So take the black hose off the catch can and put the end that was on the catch can on to the intake?

Braineack

iTrader: (62)

I just dont like catch cans.


but, the main issue seems to be that boost is leaking past your PCV (other side of valve cover) and this is pushing oil out the other side. That's why oil was spewing out.

Nothing but oil vapor should be exiting that breather line back to the intake. The catch-can is there to collect oil that may make it's way through.

If the PCV is stopping boost from entering the crankcase, then no oil should be exiting the breather...unless you have bad rings that allow too much blow-by.

Murph

So would replacing the PCV valve be my best bet? Also I am going to do a pressure test on the cylinders, had a few people bring that up.

Braineack

iTrader: (62)

Can you blow through it?

Murph

I can blow threw the large end the sits in the valve cover but not threw the small end.

Murph

Also, I just noticed that the exhaust is spraying oil. And the smoke coming from the turbo is coming from the bottom of the exhaust Manifold where it look like it is wet.

So I have come to the conclusion that is a bad seal. Thanks for the help everyone.

Braineack

iTrader: (62)

pics?

ive seen catch cans causing a pressure drop on the breather line so it becomes pretty much blocked which makes the oil return back-up (due to pressure build up) and the turbo smokes.

turbo seals dont just fail, what fails is the pressure differential.

where is your return line routed? around to the passenger side?

Murph

heres some pics of the bottoms of the exhaust manifold.

C360_2012-08-24-15-37-56.jpg?t=1345862074

C360_2012-08-24-15-39-14.jpg?t=1345862098

and yes, it runs from the valve cover across the front of the engine and into the oil catch can, and the line from the intake follows the same path, then there is a line in the bottom of the catch can the drains into the oil pan.

Savington

iTrader: (31)

Time for a compression/leakdown test.

Murph

I bypassed the catch can, no more oil coming from the tail pipe but about 4 times more smoke. Hopefully going to do a pressure test this weekend.

Murph

Turns out it is a burnt piston.