Alan

Indeed you were losing oil before you really noticed the smoke. It was either driiping out onto the manifold or getting sucked into the intake or both. I'll guess both. For the intake either it has been ingesting oil for a while - or something you did caused it to start... The flappy makes virtually no difference - it only changes the intake harmonic freq not vacuum - so I don't think its that. If you didn't change anything else...what could it be?

I would venture that you only look behind you when you are on the loud pedal if you suspect an issue - so you probably weren't looking much before now... maybe its been going on a while...

For oil ingestion you either have too much PCV suction or incorrect breather porting or too much oil in the passenger cam cover

OR you have too much blowby driving excessive flow into the only place it can go.

I'd worry about that the head oil drain you changed may be a problem or you have too much blowby due to cylinder or head issues (prob cylinder - rings/wear). The blowby could have been getting steadily worse or the oiling issue could be a sudden change.

I like the idea of plugging the intake <- cam PCV port and monitoring oil expulsion from open cam cover ports - but its unclear what to do with the crank -> filler venting (hard to get to to plug these off).

Still I think if you got any volume of oil blowing out the cam covers with the crank vent still acitve in normal driving - seems you have an excessive blowby problem rather than an intake vacuum issue.

Alan

tveltman

Alan, this is exactly what I thought. It seems to have symptoms of both problems. Not all of the plugs are black with oil, so that would make it seem like it was not an oil ingestion problem, but I find it difficult to believe that all 5 of the black cylinders would fail at once, since I replaced the plugs before I started the trip, and all of the plugs I pulled out looked clean. Thus I am absolutely positive that I was not burning this much oil before, and it seems like it was a sudden change. I will try plugging the hoses and monitoring the oil expulsion out of the cam covers and report back.

SteveG

TV: OT, unrelated, but did anybody mention getting your MAF screen replaced?
Actually, I think some radicals remove it, said it induced turbulence. But I've seen insect debris or stuff get past the air filter. If it or anything gets to the platinum wire, I don't think it would be good.

tveltman

Hmm, no, but I know the screen is not fully attached to the rim. I didn't worry about it too much because I thought the filter would protect it, but maybe not. How closely does the fuel computer monitor combustion gases? Is it possible that the MAF was previously accounting for the excess oil the engine was burning, and now for some reason it isnt? I think that sounds a little advanced for a car from 1988, but I've certainly been wrong before. I suppose a MAF swap would be a simple check, but I will do the hose check first before I worry about the MAF.

ZEUS+

Did you replace the o-ring for the spring guide/piston ? Just a small amount of pressurized oil leaking past the spring guide could be misting into vapors. This could flood the crankcase with excess oil vapor. Just a suggestion.
The breather hose is after the maf, which measures the air flow in. The oil could contaminate the 02 though.

tveltman

I did replace the seal, but I think I mentioned that the piston itself was damaged by the previous owner. He had driven the locking screw too far in and deformed the piston, and it was really difficult to remove. I did not have a replacement piston, and so I made the best decision I could and tried to file down the worst of the deformation so that the unit would float more freely in the hole, then I reassembled the whole thing. However, it was the driver's side that I replaced, not the passenger side, and according to Alan, the passenger side is the one that is responsible for oil ingestion through the breather hoses. I'm really willing to try anything I can to fix the problem. As soon as I can get my brother to help me with the car, I will poke around and see what I can learn, and I will report back. I know that I am very fortunate to have such a helpful community, and I am very grateful for everyone's opinions and advice. Thanks again.

ZEUS+

The entire engine breathing (even drivers side, which is weak) is from the oil fill housing and the pass cam cover. That is why it is common for the drivers cam cover to leak, usually at the rear. The later GTS had an improved breathing system.

tveltman

Okay, well I have more to report on this problem today. I pulled off the driver's cam cover to ensure that the oil check valve was still in place, which it was, then I tightened up the locking screw. This appears to have eliminated the oil burning at idle, but burning still occurs at 3k RPM and above, although it does not persist as long as it once did, so I suspect that was a portion of the problem. I then pulled off the PCV hoses from the passenger cam cover and removed the hose to the filler neck and plugged it. I revved the engine to 3k RPM only 3 or 4 times, and each time I saw white smoke coming out of the tailpipe. I went to put everything back together and I saw oil spattered across the intake, clearly having been thrown out of the cam cover elbow (see pics). Is this amount of oil spatter normal? What else can I do to test out what is going on? I would guess the next step is a compression check, then maybe a leakdown test, although I would need help with the leakdown test, as I no longer have an air compressor. Below are the pics of the spatter and plugged hose:

Mrmerlin

I was wondering why there is oil being blown out of the forward hole on the PS cam cover maybe because there is now no restriction with the hose removed, of course you also can inspect the junction where this hose goes and see if its filled with oil

heinrich

You really need to distinguish between white and blue and black smoke!!!

White smoke which you mention every post, is not oil. It is coolant, period.
You have massive oil ingestion which means issues anyway. Likely valve seals, but can also be that you are pushing compression into the crankcase which is causing oil ingestion from cam covers etc.
Black smoke is gasoline, which means maybe you're pulling gas into the vacuum system via your vacuum "fix" work.

I think, from given symptoms, you need to investigate a blown head gasket or broken ring or both. Look at the coolant... look at the dipstick ... any signs of mixing? Btw plugging stuff that is supposed to be connected, is not a good long-term fix. In fact, plugging the pressure relief hoses may contribute to pressure buildup.

Mrmerlin

H, he was only removing the hoses to see if that would stop the plume of smoke, it isnt meant as any fix to plug the vent hoses.
I also agree that from what the engine is doing it sounds like a possible broken ring

tveltman

Broken ring was my diagnosis initially, but when I pulled the plugs, five out of the eight showed signs of oil burning (black powder caked on). The coolant level doesn't seem to be changing, so either a very small amount of coolant can cause this problem, or it isn't coolant. Additionally, burning coolant is supposed to smell sweet. This smoke smells pretty bad. It doesnt smell exactly like oil smoke, but someone mentioned that running burned oil through the cats will cause the smell to change. Both my father and I looked at it, and when the engine gets revved, it really does look blueish white. That, plus the fact that some of the plugs are black, tells me that the car must be burning oil. However having 5 rings fail at once seems a bit unlikely to me, which is why I'm at somewhat of a loss to figure this out.

Mrmerlin is correct, I was not plugging/removing hoses as a permanent solution, I wanted to see what was going on inside the engine, and I would not run the car for prolonged periods of time with parts randomly disconnected. I'm starting to think that I am at the limit of my expertise and ability to diagnose. I've not ever had a problem figuring out what was going on with the car, but it may be time to call in some extra help, because I just find it difficult to believe that five of the rings would go at once, very suddenly, when all 8 old spark plugs came out 3000 miles ago with NO signs of burning oil. Since the plugs are oiled on both sides, that would imply that both head gaskets are blown. I don't know how likely that is, but I have a feeling that it isn't, really.

heinrich

If it is oil, it can be entering your combustion chambers only as follows:

1) broken ring, scored cylinders <edit: as stated, also valve seals/guides>
2) breather hoses

So, if you plugged all possible holes for oil ingestion and cleaned up the residual oil in the intake and throttle body, then see option 1.

heinrich

Instead of removing the intake, you could potentially

1) buy the seals for the side covers of the intake and then
2) remove side plates and clean inside the intake.

From the huge ingestion you describe, sounds like it is ongoing ingestion though.

tveltman

I agree, heinrich, I just am having trouble figuring out how five cylinders can fail at once. Can it not also be drawn in through worn valve seats, etc?