To cap or not to cap (PCV related)::Leak down 10/24/09l::

MA70Snowman

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Oct 17, 2006
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Poodles;1428096 said:
Have you done a compression/leakdown test?

Poodles;1428176 said:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190

Only thing I can think of is either blowby or it's lifting the head and leaking in the oil jacket (not likely).

SWEET! Thanks for the link man. I'll be putting that on order come pay day. I agree w/ the blowby. Everything is pointed PCV related. Only thing I can really think of. Hopefully sunday I'll have another chance to tear the front cover appart and hopefully w/ the UV dye I can pin point a leak.. and should have the leakdown testor. We'll see. I think I'll start driving it to work tomorrow and see how things are. I'll stay out of boost until sunday and then boost sunday and see what happens.
 

dragracer

GearHead
Oct 31, 2005
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Churubusco
First: suction will show that there is vacuum in pcv system when everything is hooked up.

Second: the throttle body port isnt small. Its pretty much that size all the way thru (around 1/2 inch). Unless thats what you mean by small.:icon_bigg

Third: This is exactly what my car did. Only smoked AFTER boost and letting up. Believe me when I say I went thru the same headaches. Mine just didnt leak externally.

Excessive crankcase pressure is whats causing this. Malfunctioning pcv system and excessive blowby will cause this. And they are both tied together sometimes. And double check tb port. If spraying cleaner thru it before you called it done still came out dirty, then it needs more cleaning. That stuff gets hardened in there you know. Since the condition somewhat change after this, maybe its still restricted some. Dont take this the wrong way.

Post leakdown test results when you get it done.

Post if you pinpoint the leak too.

If all else fails.......:beer::beer::beer::beer::puke:



Rich
 

MA70Snowman

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dragracer;1428569 said:
First: suction will show that there is vacuum in pcv system when everything is hooked up.

Second: the throttle body port isnt small. Its pretty much that size all the way thru (around 1/2 inch). Unless thats what you mean by small.:icon_bigg

really 1/2? I looked in the back side of the TB. and the initial passage was 1/2 but it looked like maybe 1/2-3/4" back it reduced in size down to no kidding pin hole sized. I would try and get pictures but I doubt I could show it. Its hard enough to see w/ the naked eye. I might see if I have a 89+ TB laying around and just throw that one on there and see what happens. But yes the TB port is cleaned.. that much I will garuntee.\


::UPDATE::

okay I decided to run outside and check for SUCTION on the oil cap. I pulled the cap started the car. (VERY COLD) popped the cap off and held my hand against it.. I could feel air BARELY moving... but I couldn't really tell if it was in or out.. So I ripped a section of plastic bag (a pep boys bag) and set it over the opening. at IDLE.. it bouced up and down VERY rapidly. like the engine was under some serious vibrations (just a description.. the engine wasn't) and even to see if it was the engine vibs affecting it.. i moved the plastic bag to the other side and it just sat there... this is under idle.. Now when I reved it.. and held around 2-2.5K the plastic blag was blowing OUT!! the opposite of suction. SOOoo.. can anyone please explain these results of this very ghetto test?
 
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dragracer

GearHead
Oct 31, 2005
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Churubusco
Pull the hose off the tb port (the one that goes to valve covers) See how much suction you feel there(vacuum). If that port isnt restricted, you should get a bunch. Thats why i said to check the oil fill cap. You will get some there if vacuum is being applied to the crankcase. I will double check my tb but mine didnt have a very small airway. It was basically the same size as the port you see on the outside where your hose hooks up.

Rich
 

MA70Snowman

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dragracer;1429496 said:
Pull the hose off the tb port (the one that goes to valve covers) See how much suction you feel there(vacuum). If that port isnt restricted, you should get a bunch. Thats why i said to check the oil fill cap. You will get some there if vacuum is being applied to the crankcase. I will double check my tb but mine didnt have a very small airway. It was basically the same size as the port you see on the outside where your hose hooks up.

Rich


OKay I pulled the hose of the TB.. good suction. (not as much as the IAC port, but a significant pull) I pulled my NA valve cover pipe off and plugged both ports.. good suction.. then i put it all together and put my hand on the oil cap.. nothing.
 

MA70Snowman

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MA70Snowman;1431495 said:
OKay I pulled the hose of the TB.. good suction. (not as much as the IAC port, but a significant pull) I pulled my NA valve cover pipe off and plugged both ports.. good suction.. then i put it all together and put my hand on the oil cap.. nothing.

bump for any thoughts.. i've been waiting for my leak down tester from harbor freight. no word on it though.
 

MA70Snowman

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YAY!!! I got my leak down tester... and It didn't tell me anything!

I zeroed on the #1 cylinder. went to #2 and it showed a 52% loss. went to #3 and it showed 5% increase, so I re-zeroed on that one.. went to #4 and it was a 3% loss. 5 and 6 were the same. went to 1 again and it was a 2% loss. i RE-did #2 I was pretty sure I had it on the intake or exhaust stroke last time this time it was a 2% loss.. So here's the final #

#1 - 2% loss
#2 - 3% loss
#3 - 0
#4 - 2% loss
#5 - 2% loss
#6 - 3% loss

the numbers show all good right? On most of them I heard air comming out the oil cap which I assume is normal given that there will be SOME blow by correct? i mean it wasn't a huge ammount. so can offer some insight on these #'s? and maybe some insight into my on going issue?
 

MA70Snowman

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bump for any insight, I'm beating my head against the wall. I'm hoping IJ comes back as he was pushing for the leak down test. I was really hoping it would've come back with issues. ANY help please.
 

adampecush

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May 11, 2006
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Edmonton
dragracer;1429496 said:
I will double check my tb but mine didnt have a very small airway. It was basically the same size as the port you see on the outside where your hose hooks up.

Rich


There is an orifice in the PVC port on the TB. ~2 mm in diameter iirc. It is only apparent when the TB is off the car. Blow through it and you will realize that it is there.
 

MA70Snowman

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Oct 17, 2006
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IJ.;1437002 said:
Numbers actually don't look right to me...

Where was the piston for each check?

Pistons were TDC, on the compression stroke. I'll double check tomorrow and even take pictures, I did the procedure according the the little paper that came w/ them. "Set piston to TDC have the regulator turned ALL the way down/off. On the first piston increase pressure until the 2nd gauge reads ZERO" and that is your zero point to compare all the other pistons to. They say w/in 5% is good. at 10% you need to ask questions. Thats why when I got to cylinder 3 and it was over the zero, i set that piston to my zero and redid 1 and 2.

adampecush;1437101 said:
There is an orifice in the PVC port on the TB. ~2 mm in diameter iirc. It is only apparent when the TB is off the car. Blow through it and you will realize that it is there.

Yeah so thats what I was seeing. I'm assuming that's to help accelerate the air comming in. (or something like that related to physics and boyle's law.. right?)