No smoke then lotsa smoke

[gibbon]

So I'm still halfheartedly trying to fix the starion even as it disappears out the door. The thing fires up first crank and appears to run perfectly for a few minutes, then suddenly like a flip of a switch the revs drop them start rising and falling every couple of seconds like the idle motor is chasing itself, and it starts smoking out the exhaust. Given the timeframe I suspect it's as it's coming off it's auto choke configuration or going into closed loop, but not too sure why it would cause the smoking? I always assumed it was blue smoke but s guy today reckons it looked white to him. Thoughts? Next steps to diagnose? 

[tortron]

Is the fuel really old?

 

 

 

[bigfoot]

Turbo dying? I have that spare one sitting on shelf

[gibbon]

4 minutes ago, tortron said:

Is the fuel really old?

 

 

 

some is extremely old. some is new. some is avgas 

[gibbon]

4 minutes ago, bigfoot said:

Turbo dying? I have that spare one sitting on shelf

is that the symptom of a dying turbo? This one is definitely blowing oil out the compressor but it spins happily enough at idle, I don't think it's seizing or anything 

[bigfoot]

Is it pumping oil into the intake?

[gibbon]

it definitely is, but isnt it weird how it doesn't smoke at all until the car warms up. and when it does, it's instantaneous. the revs abruptly drop, the smoke abruptly starts 

[Alfashark]

How's the compression when it's warm?  

Thinking you may have the reverse issue that plagued a lot of Bountys - They'd smoke like a motherfucker when cold, then when they got a bit of heat in them it stopped - Cracked heads I think in their case.

Seems like something expanding when warm in your case and allowing oil to pass.

[HighLUX]

Sounds like valve stem seals to me. ICV is open when it warms up so intake vacuum is low, soon as its warm that closes up and the vacuum ramps up which sucks the oil thru

[gibbon]

could be this, just to add some more info this is what else I tried:

I blanked the oil feed to the turbo, pulled the inlet pipe off, disconnected the airflow meter so it was in limp mode, then held the compressor with my fingers to stop it fucking the bearings by spinning with no oil. And what I found was it only smoked after I snapped the throttle shut, ie at high vacuum. I put it down to not having the pcv functioning as the inlet was disconnected, maybe it's sucking through the stem seals... this is a head I hadn't used prior. Is there a way to really isolate a stem seal issue?

[gibbon]

12 minutes ago, Alfashark said:

How's the compression when it's warm?  

Thinking you may have the reverse issue that plagued a lot of Bountys - They'd smoke like a motherfucker when cold, then when they got a bit of heat in them it stopped - Cracked heads I think in their case.

Seems like something expanding when warm in your case and allowing oil to pass.

Haven't tried a compression check but starting to think I'd be best served by swapping my old head back on, be it stem seals or cracked head. 

[gibbon]

how fast can I swap a head out. do I have the mojo. do I want to buy another head gasket. oh god I'd have to make another inlet gasket because they don't exist anymore..... etc etc 

[shizzl]

My GTX rally car had those exact symptoms. Was a dodgey head gasket, even though it was 60km old. 
 

once it got to temp it started pushing everything out. 
 

I had that job down to an hour by the time I sold it. It’s still going 2 years later

[gibbon]

ok well it sounds like I know what needs to be done

doesn't mean it's gonna actually get done, but still... 

[cletus]

White smoke can be brake fluid , check its not leaked into the booster and is chewing on that ? 

[shizzl]

15 minutes ago, cletus said:

White smoke can be brake fluid , check its not leaked into the booster and is chewing on that ? 

Compression booster

[gibbon]

8 hours ago, cletus said:

White smoke can be brake fluid , check its not leaked into the booster and is chewing on that ? 

can't say I checked for that, I guess I just blank off the booster vac line?

[tortron]

11 hours ago, gibbon said:

how fast can I swap a head out. do I have the mojo. do I want to buy another head gasket. oh god I'd have to make another inlet gasket because they don't exist anymore..... etc etc 

I can scan the flange and have my cutter wizz them out probably

[cletus]

1 hour ago, gibbon said:

can't say I checked for that, I guess I just blank off the booster vac line?

Yeah just disconnect it and block it off and run it 

 

It's not a common problem but easy to check and cross off the list 

[ajg193]

There's a whole lot of assuming going on here.

 

Have you tried just taking it for a good half hour thrash to see if it clears out? It could just be a buildup of oil in the exhaust, @h4nd has plenty of experience