Compression test results!
TECH Apprentice
Joined: Jul 2006
Posts: 326
Likes: 7
From: Columbus,Ga
To do the test, we didn't have all the spark plugs out, so yes that is possible it threw that number off, but it didn't change any of the others even with only 1 plug removed. We pulled the fuel pump fuse, hooked up the tester, and cranked it about 4-5 times. Cleared the guage, and then did the same cylinder twice to make sure. We didn't have the throttle body open. I just did the basic stuff to do the compression test, i'm pretty sure we did it just fine. I'm thinking about seafoaming the car to help get rid of all the crap which is probably in there.
So if my numbers seem acceptable, what would cause it to burn oil, and put out a big blue cloud under WOT, am I looking at valve seals for sure?
So if my numbers seem acceptable, what would cause it to burn oil, and put out a big blue cloud under WOT, am I looking at valve seals for sure?
Yeah it's mine, awesome for a picture not for the wallet when it landed..... No carbon buildup on my pistons either. Sorry for the sidetrack guys carry on with the "tech".
Usually when the rings go bad you get lots of blow by. In my experiance its usually the valve seals (non ls1 experiance). I have a 97 ford expedition 190k that I've owned for seven years, It burns a quart of oil every 1k since I've owned it. Just switched to castrol high mileage and 5k later it is a half a quart low, that is one tenth of what it was! Try it and post the results.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
Been trying to figure out why I've been burning oil and was trying to figure out if it was rings or vavle seals. Finally had some time to do a compression test, and at the same time put new plugs and wires in. The results are as follows (I don't know the firing order off the top of my head, so I just did them as each side from front to back):
Car has 128,xxx on the clock.
Driver side, front to back:
185
200
200-203
200-203
Passenger side, front to back:
195-200
200
198-200
195
Everything was pretty much even except for the front cylinder on the driver side. Additionally, we noticed something very strange with that plug. It doesn't want to thread in all the way, it sticks out a little farther than the other plugs. It was like that on the old plug we pulled out, on the compression tester tool that we screwed in, and on the new plug we put in afterwards. It just doesn't go in as far. I figure there might be some gunk or something blocking the threads? It doesn't seem to be affecting anything either so I'm not sure what to do about that.
Also, a new thing we noticed was that when I go WOT, there is a big blue puff of smoke that comes out. Tried it twice, did it both times. Hopefully this can help me narrow it down. What do you guys think? Thanks in advance.
Car has 128,xxx on the clock.
Driver side, front to back:
185
200
200-203
200-203
Passenger side, front to back:
195-200
200
198-200
195
Everything was pretty much even except for the front cylinder on the driver side. Additionally, we noticed something very strange with that plug. It doesn't want to thread in all the way, it sticks out a little farther than the other plugs. It was like that on the old plug we pulled out, on the compression tester tool that we screwed in, and on the new plug we put in afterwards. It just doesn't go in as far. I figure there might be some gunk or something blocking the threads? It doesn't seem to be affecting anything either so I'm not sure what to do about that.
Also, a new thing we noticed was that when I go WOT, there is a big blue puff of smoke that comes out. Tried it twice, did it both times. Hopefully this can help me narrow it down. What do you guys think? Thanks in advance.
If your compression gauge is working right, then you have good compression...
If you're blowing oil smoke, peek inside the intake manifold, sounds like you have oil pooling on the manifold floor (sucked in via PCV plumbing).
If you combustion chamber deposits (did you observe this on your old plugs...?) then run some top engine cleaner.
To avoid deposits (or to blow them out), make sure that each time you drive your car take it on one or two 4000+ rpm WOT excursions (i.e. get up to peak torque)... do drive safely tho.
Joecar, thanks for the reply. I'll try the thread chaser idea on that spark plug when I get some time, sounds like a good idea. We tried to look into the manifold but didn't have a flash light so couldn't really see. There wasn't any oil at all on the tb blades or past them, as far as we could reach, so I just need to check again with a light and see. I do have a catch can hooked up, so I shouldn't be pulling oil through the pcv, but who knows.
The old plugs looked fine, they weren't fouled at all, but I decided I might as well replace them while we were at it.
I've been trying to decide if its the valve seals, since my compression is alright and seems like it might not be the rings. I need to do a leakdown test to be sure obviously.
The old plugs looked fine, they weren't fouled at all, but I decided I might as well replace them while we were at it.
I've been trying to decide if its the valve seals, since my compression is alright and seems like it might not be the rings. I need to do a leakdown test to be sure obviously.
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