Why am I burning oil?????

I need some super sherlock mechanic diagnosis/troubleshooting here. Since ive had my 348 i have been burning oil. Very negligible amount when just idling, so when i bought the car i fogured it was just a valve guide or something that needed to be adjusted whenever i get to doing the major... Well it was a nice day, so i figured id spend some time in the garage today and pull the plugs to do a compression test. When i pulled them, none of them were oil fouled, slightly dark, but not aweful. So now for the compression check... All of my compression numbers were 190-195! This is where i thought i was going to find my problem, as i suspected one cylinders rings were going to be bad, thus letting by oil, and burning. But no. Perfect numbers. Im not burning oil on startup, only after it warms up, so there goes the valve guide idea... I looked in the air box, and its dry, so no sucking any up through the bypass there.

So after checking everything im left with three more possibilities that i can think of... And if you think you already have the answer, stop reading and type it, because i dont want my possibilities to sway someone elses expert opinion...

1.) could a bad valve SEAL cause this? Only smoke after warm? Or would it give the same symptoms as a guide where it would burn the oil on startup?
2.) could i possibly have the wrong viscosity of oil? Possibly too light so it is getting past the rings or valves somewhere? Could changing oil weights make a big difference? If so, what exactly should i try?

Known issues that may be affecting this:
1.)my secondary air injection tubes arent hooked up right, the vacuum lines lead from the white inline vacuum "switches" to nowhere... And those lines are all dry
2.)my car was de-catted, and the o2 sensors were deleted. I have constant CEL's.
3.)I also have a CEL code on both sides for coolant temp sensors (my fans stay on forever)
4.)the car doesnt start on the first crank when cold. I have to turn the key all the way off, and re-prime the fuel pumps for it to start. I think i may have low pressure or some sort of problem with getting fuel to the engine, but runs fine once its started. Occasionally there will be a slight bog, where it feels like both banks arent sync'd while driving, which again points me to a possible fuel pressure problem.

My second question relates to number 4 above. If i am getting too low of pressure, could i be running lean, without o2 sensors, could this cause smoke in the exhaust? Smoke that smells like oil (not likely)? To answer your next question, the oil does not have an obvious blue color like normal oil burning in the combustion chamber, its more of a white, however it is NOT coolant. It is not sweet smelling, and my oil nor coolant are discolored. I can only think the smoke is either lean fuel or oil.

After sitting and idling in the garage, you can see the smoke faintly. If its warm and you rev it slightly in the garage it comes on a little bit more, if you take it for a drive, you cant see smoke coming out the back while driving, but when pulling to a stop sign or light, it plumes for a few seconds then dies down back to normal...

I think ive written every possible detail i can think of, now its time to HELP!!! Bonus respect for anyone who can solve this problem for me without me having to pull my engine or heads!

 

Half between full and add marks

 

I agree about the o2's, but i have read on other posts here that o2 sensors only affect the engine at idle? Or was it the other way around? Crap, now i feel foolish... Anyway, oil is clean, oil is definitely not burning ON the engine, its burning through the exhaust. Not leaving any oil spots on the ground. I would LOVE to get the o2s back but i havent made any stooge friends here on Oahu, and the pigtails for the o2's are nowhere to rven be found on the engine harness, so my little brain cant fathom where to start woth getting those back... And the service prices on this island are a good 30% higher than those of the mainland, so im trying to do the "little things" myself.

 

Thanks ricambi for the photo. Problem is mine only has the mounting points for where the o2 sensor harness ends would be, no wires. Ive been all over the engine, even deep inside the manifold valley with my videoscope and cannot find any wire ends that would possibly connect to o2 sensor wires. Its just blank space. So the temp sensors wont be too hard to replace, but the o2's may need a complete rewire into the main harness.

On the temp sensors, when i pull them out, will that put a lot of air in the cooling system? If so, is there a good way to purge the air?

On checking the oil, yes i have read the entire owner and service manuals cover to cover multiple times. Im well versed on how to check the oil because overservicing was my first thought when i saw the smoke on a dry sump system. I check the oil while idling at OPERATING oil temp. Of course, the previous owner DID overservice it, because why wouldnt he? He messed everything else up, so why not the oil too? So i drained it to proper level the week i bought it, and i have driven about 400 miles with no change in smoke. Consumption seems about right in accordance with the manual too.

So i will replace my coolant temp sensors, and hopefully someone can point me in the direction to go with the o2's...

 

It has two tps, and the ecu models come up as 2.7 as well i believe.

 

Im on the fence about it, its just too beautiful to give up on. Just wish i had a checklist of what to do first. I hate to say it but i may have to bring it in to JN Exotics just to have them do the o2's or tell me where the damn wires are at least...

 

And i only had it up for like 3 hours, but had 5 calls and 3 different texts. Thats when i knew i needed to take it down.

 

So after camping out in the garage for a week, i finally dug far enough where i found some good and bad news that i may now need more help with. Since my air box, air tubes, throttle bodies and filter were all dry, i figured i would check inside the intake manifold just to fully rule out oil coming in that way. Stuck my video scope in the throttle body and found it was very wet. Not soaking puddles of oil or anything, but wet enough to get smoke if it gets in the cylinders, which im betting it is. So i said to myself, wtf? Why are the entire intake paths dry, but there is oil in the intake?? Lead me to believe i should kill myself because its probably an intake manifold gasket. So instead of taking a straight razor to my wrists, i thought, hmm, i guess ill check the oil tank overflow hoses one more time. The ends where they meet the intake tubes were dry (so i thought), but i hadnt checked from the t-fitting all the way back to the tank. Sure enough, inside was pooled with oil, so much that it was even slightly leaking past the hose clamp at the t. Looked dry from above but until i wrapped my whole hand around it, i didnt realize there was oil there. Luckily it didnt burn all over my engine to get smoke from the engine compartment, but it was still leaking. So now i have the entire oil tank overflow hose assembly off. Im going to clean it out, and then reinstall.

So here-in lies my problem. Why, even though the oil is NOT over-filled, am i still pooling up oil in this hose? Why is it leaving the tank? Could it just be residual oil from when it WAS overserviced? If so, why hasnt it burned off yet? A couple hundred miles since the oil level correction and still burning what is in that hose? Or is something causing oil to flow through it?? Ugh! Guess after cleaning it and reinstalling, ill take it off again after a few miles to check if its wet again.

Since i have my airbox off, im going to do an oil change to Mobile 1 0w-40. Does anyone object to this? Also while the filter is off ill be replacing my coolant temp sensors. Am i going to leak coolant everywhere when i pull the sensors? And how can i purge the air if coolant leaks out?

Thanks for the support guys, ill get this baby back to tip top if it kills me!

 

So i just HAD to put all the hoses back on and run it ONE MORE TIME (without the oil change or sensors done yet), after cleaning the hoses of all oil inside. Seemed like success until the usual 15 minute idle had elapsed, the oil temp needle started to rise amd then like clockwork... Smoke. Seemed like almost MORE this time. It does fine even when engine gets to operating temp, just as SOON as the oil temp needle livens, smoke comes on. Really makes me think its the wrong viscosity. But i guess still could be the temp sensors, so might as well take it all back off and but the bullet. This suuuuuucks.

 

Is it possible to bypass the oil blowby hose that puts it back into the intake? Why would anyone want extra oil going back into their combustion chamber anyway??? This has got to be where my oil burn source is coming from.

 

63k. So definitely a driven car, which im fine with, just wish i wasnt burning. Im not too concerned with the rings as the numbers are good. Maybe once the blowby stops ill do another compression test, that way ill know its a dry test.

First things first i have to get the temp sensors changed out. Whats the best way to lower the level of coolant just enough to be below the sensors? Or am i SOL and will have to drain the entire system?

 

Thank you mike. I greatly value your expertise. Ill get the temp sensors replaced then ill bag the end of the blowby hose to see how much im getting within say 100 miles... That should tell me more. There has to be some acceptable amount of blowby, otherwise i would think it wouldnt be a recirculating system. If they had it drain onto the floor of your garage, rather than back into your engine, i think people would worry a lot more about it.