bnavarro

I got a DSM(90 TSI AWD turbo) I just replaced the head and turbo. I did lots of other stuff too. I'm noticing i'm burning oil only when i shift gears. Like a big puff of blue smoke. I have good compression with 150 all across the board. Some people mentioned valve stem steals, but i just had the head replaced. i'm getting no puddles of oil in my intake or exhaust pipe. Any idea's?

jqturbo

If you have a DSM question especially, go to this forum, and they'll know what's up!
Link....http://orl.dsmforum.com/

bnavarro

yea, i tried a couple of web sites, but pretty much all the same.

jqturbo

Sorry man! I've gone to them for problems and they've helped me out! Wish I can help, but not too "techy" when it comes down to breakin' down engine issues, just basics!

Good luck though!

sgmotoring

worn piston rings or car running too rich?

Sly Raskal

iTrader: (1)

if you only burn oil when u shift gears and not when the car is at idle it sounds like a tranny/clutch issue to me, but i'm probably wrong.

bnavarro

well, if i had bad rings, i would get bad compression. If i was running rich there would be black smoke, not blue. Thanks for the idea though.

Zapata

just a shot in the dark.....check your oil lines in and out of the turbo??

NSXNEXT

iTrader: (2)

Did you install the upgraded fetzer valve?

allmotor_2000

That would be the rings most likely.

scalbert

I would have to agree, it sounds like the rings. Are you sure your color qualification system is properly calibrated and that smoke ain't dark gray?

DSM's are known to go rich during shifts.

allmotor_2000

You mean flux capacitor

bnavarro

Flux capacitor is good. 1.21 gigga watts. And i'm sure the color is blue. i get the black smoke when i punch the gas. How else would i check the rings. i did a compression test.

allmotor_2000

If its the oil-rings... then you probably won't see it with a compresson-test - do a leakdown test; might prove more worthwhile.

EricL

As mentioned, you can have good compression and a very messed-up oil ring. The oil passing by it will actually make for good compression by helping to “seal” the rings. Squirting oil in through the spark plug hole can be used as a diagnostic test to see if the compression goes up when rings are worn; it’s an old trick…

Can you get the car going down a pretty good incline where you need 2nd gear to keep the car from speeding up (you want to create some serious vacuum)?

Leave it in 2nd, and then pop the throttle -- does blue smoke come out of the tailpipe?

If the top end is good, as mentioned, you probably have a bad oil ring. I've seen this problem on more than a few cars...

JD22CL

Ive actually just installed a Twin-Flux Capacitor on my 2.2, I'm now runnin the 1/4 year in about 12.6 seconds...haha

bnavarro

A leak-down test was next on my list of things to do

chef chris

BINGO.

I believe that would be the cause. My 90 Supra did the same thing.

bnavarro

well, i took it out for a ride today. It was sunny out, so i could tell what was going on. I'm getting blue smoke when i'm accelerating, and very noticable when i shift. And it smells like oil burning too. Very weird. But i'm getting good compression. I don't see anything wrong with the oil lines.

allmotor_2000

I suppose it could be the turbo too, but then it doesn't quite explain only during shifts!

chef chris

Blockage is usually the problem with the lines, they won't look different from the outside. How old are they? If you don't know or they're over 50K, I'd get some replacements...

Even if they aren't your problem, it's a good maintenance item to replace & is insurance for your turbo.

I wonder if blow-back into the intake charge could be sufficient enough to cause any smoke

Maybe valve-guide seals(sp?). They were a cause of smoking on my old Supra...sorry, don't know much about the Mitsu.

jqturbo

:sqnteek: Hhmmm, gotta get me one of those!

bnavarro, let us know what the problem was once you pinpoint it! -- see who was right!

bnavarro

Well, originaly, i was just gonna replace the head due to broken stud bolts. After that, i changed the turbo. Turbo feed line. Cleaned the turbo oil return line. The block has 100k on it. So to sum it up. It's got new oil lines, turbo, complete head including valve seals. I'm gonna check it out some more tomorrow. Now if it is just the oil rings, how would i go about testing them?

EricL

Process of elimination (outside of very, very weird problems). I went through this same exercise (no turbo), and all of the references and mechanics say, "If you have oil smoke when you 'back off the throttle', it MUST be the valve guides or valve seals. Well, they all got replaced and the car still pumped out oil. When we did a compression test the compression was good, but not stellar. We did get a bump in compression whenever we squirted in some 30-weight (5-30, etc will do).

If and when you do the leak down you can diagnose by where the air sound comes from. (Plenty of conventional info on leak down testing is available.)

One thing you might consider doing is opening up the oil filler cap. If you see blow by – with the engine running -- you got a problem, and it's probably the rings.

In general, the compression test + leak down test will eliminate the valves, coolant leaks (N/A), valve seals/guides, etc.

If you can’t find any other device on the car that sees vacuum + oil, you should look at the rings as the default. I never got a dead positive confirmation on my engine. However, it was old, had a lot of hard high-rev miles on it, and all of the other items were OK. By process of elimination, it had to be the rings (I had no other emission stuff or goodies that were hooked up to manifold vacuum AND oil.) The bottom end got rebuilt and bored, and there was no more smoke.

Here is a link that may be of use:

http://www.hastingsmfg.com/Service%2...il_control.htm

Have a look, and here is just one small excerpt:

“The piston fit in the bore is important because on the downward stoke it is the pistons skirt which first shears the oil film prior to the piston ring passing. If the oil film is too thick the piston ring will "hydroplane" over the oil and it will be scraped to the combustion chamber on the upward stroke where it will be burned.
Skirt design determines how effective the pistons oil shearing ability is. For example the old style full skirt pistons which are bore size around their entire circumference are more efficient oil scrappers than the current open slipper type pistons of today. The open, or modified slipper pistons are necessary to clear crankshaft counter balances although full skirt pistons are still used in some engines.
Oil drain back in the oil ring area of the piston is important to good oil control. If the oil scraped by the oil ring cannot be removed or drained rapidly behind or under the oil ring, it will cause the oil ring to ride over the oil film leaving too thick a film on the cylinder wall. Since the oil ring is responsible for scraping the largest part of the oil film from the cylinder wall, drainage of this oil down the inside of the piston must be efficient.

bnavarro

Yea, i think i'm gonna have to do the motor. Look at it this way. I got a new car. I spent alot more $$$ then i expecited, but shit is gonna be fast as fuck.