I have a bad misfire so today I did a few tests, what is your interpretation of the compression tests?
I did both dry (first) and then wet (added oil) and got the following average compression readings (3 tries per)
DRY WET
Cylinder 1 96 105
Cylinder 2 110 127
Cylinder 3 95 116
Cylinder 4 100 110
Cylinder 5 110 120
Cylinder 6 100 120
Note: the wet test was performed by adding about 15cc of Lucas power steering stop leak oil (thick oil I happened to have available).
My understanding of these results are:
1. At the low end of the acceptable compression range.
2. The variation in compression between cylinders is acceptable.
3. The increase in compression from the addition of oil points to worn rings.
I am currently running mobil 1 high mileage 5w30 full synthetic; based on these results, perhaps I should run a higher viscosity oil. I recently changed the oil after 5k miles and if I remember correctly, I had to add a quart of oil (possibly 2?) over that time/miles. So it is burning/leaking some oil; however, it doesn't smoke and there aren't oil spots/leaks under the car. Note that I have only put about 7k miles on the car since buying it 14 months ago.
I also feel that these results wouldn't be the cause of my misfire problems.
Although not a great picture, here are the plugs. cylinder 1 looked different than the others, but none looked really bad and none were oily.
[IMG]
[/IMG]
So what do you think?