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Propane trick? Isn't that trick for intake vacuum leak only?
You are chasing two distinct, unrelated vacuum leaks, right? An intake vacuum leak, and a crankcase vacuum leak. Right?
I think we are confusing these two things over and over and over again in this thread. I suggest you start a separate, new thread for the intake leak, and keep this one for just for the crankcase leak (since that is what this thread started as).
Propane trick? Isn't that trick for intake vacuum leak only?
You are chasing two distinct, unrelated vacuum leaks, right? An intake vacuum leak, and a crankcase vacuum leak. Right?
I think we are confusing these two things over and over and over again in this thread. I suggest you start a separate, new thread for the intake leak, and keep this one for just for the crankcase leak (since that is what this thread started as).
I wasn't aware of the difference, assuming that an intake leak would also cause oil consumption/burn? And I don't know if I have a crankcase leak, which is why I'm spinning my wheels here trying to get an understanding of what I'm suppose to measure, how I'm suppose to measure it and with what.
Still trying to get the lightbulb to come on upstairs:
Intake and crankcase, the air in one doesn't touch the air in the other.
Intake air is all the air above the pistons. Air into intake, into throttle body, im, intake valves, combustion chamber, exhaust valves, and finally out the exhaust. An intake vacuum leak is any leak after the throttle body, and before the intake valves.
You can use the propane trick here by letting the leak suck propane, which richens the mixture into combustion chamber, affecting idle speed. You move the unlit propane torch slowly around all the suspect leak points, and when idle changes, you found the spot.
The combustion chamber air is all the air 'below' the pistons. Air in the block, around the crank, rods, bottoms of pistons, etc. But also the air inside the valve cover. Around the tops of the valves, etc.
Its easy to imagine the piston rings keeping intake air separated from crankcase air. Well at the valves, there are the valve seals and valve guides that do something similar. The air in the valve cover is above the valve seals, so its not intake air.
Does that make sense?
So tbe crankcase air we're discussing here needs to be at the correct pressure to allow those piston rings to seat properly, seal properly. If they don't, than that function of separating intake and crankcase is compromised. The result is crankcase oil gets past rings into combustion chamber, where it combusts and goes out tailpipe as wiffs of blue smoke (and damages cat as well).
So the whole point of this thread is this thing we almost never think about, crankcase pressure, can have a dramatic impact on oil consumption. Along with that concept is where to look for crankcase leaks, and how to test for them.
If you are chasing an intake vacuum leak, none of the thoughts in the original parts of this thread apply, unless you also happen to have an unrelated crankcase leak.
If you aren't using oil, you don't have a crankcase leak or at least not one that is causing any negative effects yet.
Go sort out your intake leak first. Then if you have oil consumption, return here to see of crankcase air leak is paet of the problem.
Sorry for the long post, felt it necessary to clear this up.
@Car Analogy This actually IS very helpful, thanks! I had thought a leak is a leak is a leak, so now I understand to separate the effort. Tomorrow I take delivery a nifty smoke machine to help sort this out, based on what you wrote, where would you recommend I stick the smoke into to find the leaks? I've watched tons of videos but am still not clear where (if vacuum leak is after throttle body, do I remove the intake filter and stick the nozzle in there?). I presume I can use the smoke machine to first find the intake leak, and then a crankcase leak...sorry if I'm still confusing the two, but it is starting to make sense.
I got this bad boy which has great review, and a few hose plugs to help with the project:
For the intake leak, I would remove the thin hose that connects im to valve cover (to the pcv valve in the valve cover), and connect smoke machine there (so smoke poimts to im)
I would use this same spot to test crankcase as well. Connect it so smoke point to im for intake leak. Remove pcv and connect smoke to where it was in valve cover for testing crankcase leak.
For the intake leak, I would remove the thin hose that connects im to valve cover (to the pcv valve in the valve cover), and connect smoke machine there (so smoke poimts to im)
I would use this same spot to test crankcase as well. Connect it so smoke point to im for intake leak. Remove pcv and connect smoke to where it was in valve cover for testing crankcase leak.
Reporting back with results sir!
And they are inconclusive at the moment...here's why.
I conducted the tests as you suggested with a slight modification, note in the two pics I injected the smoke into the Intake Manifold and blocked off the breather tube into the Head. I also removed the Air Intake Cone. The only place the smoke came out of was the Intake Cone Hole location, I did the test three times and could not find any smoke coming from anywhere else, it all poured out of the big open Cone Hole. Does that sound correct that it should do that? I don't know if this is normal or if the smoke should have stayed in the IM and not poured out of the Cone Hole.
Next, I injected the smoke into the Breather Tube hose and plugged up the hose leading out of the PCV pipe, and did this test twice, and saw no smoke come out of anywhere.
Lastly, I stuck it in her rear end, she took it well with no leaking anywhere....nice and tight.
So...I inspected and then redid my valve adjustment, and put the intake and exhaust a bit looser. The result? The Negative Short and Long Term fuel trims have reduced by about 60% (so from -10.5% average, it's -4.7%). I've always held the belief our cars perform better with the valves on the looser end, and read several tuners on here, having rich conditions with tighter valves, loosening them up with similar results and benefits. I've always thought tighter spec'd valve lashes cause more problems down the road. I may loosen them up a bit more to see if it continues to improve the rich condition.. Later today I will also be replacing the Primary O2 Sensor with Honda OEM and see if that also helps and will report back.
Alright folks -- cross your fingers. I have replaced the following on my AP1:
New oil cap gasket (old one was so flattened )
New dip stick (because you can't buy the gaskets -- old one was SUPER loose )
New PCV valve and PCV gasket ()
I have been burning oil forever, at least for the 8 years I've owned the car; it's a 2002 with 120k miles, probably burning roughly ~1 quart every 2-4k miles, depending on VTEC yo.
I've now read through this whole post and it sounds like a possible simple fix to a nightmare problem... if it works. (Hoping it's not like the mythical shin etsu grease "fix" for roof leaks ).
I had a compression test carried out on mine a year or 2 ago and the numbers were fine and consistent across all cylinders so this could be light at the end of the tunnel for me.
Thought I'd compile the parts list in this post:
New oil cap gasket (old one was so flattened )
New dip stick (because you can't buy the gaskets -- old one was SUPER loose )
02-13-2019, 12:44 PM
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