I just did a compression test today and got some numbers I think are really low, 160 170 160 165. Does anyone have any suggestions as to things that could be wrong? One strange thing was that on the first cylinder for the first couple of chugs a little fluid seemed to splatter out of the spark plug holes. My car is a 94' GS-R with just over 100,000 miles. The engine was a normal operating temperature (I pulled into the garage and turned it off, then started almost immediately). All spark plugs were out. I let every cylinder pump away untill the guage wouldn't register any more pressure (7 or eight times each). I was wondering if elevation would do anything drastic to effect compression number, as I'm at 7220 feet (wishful thinking perhaps). If anyone can help it would be greatly appreciated, thanks in advance.

 

When I did my compression, the first 4 or 5 cranks gave about 180-190 then at about 7 or 8 cranks, i peaked all my cylinders at about 210 psi.
What is the correct compression, the peak no. or the value yielded at 5 cranks?

thanks
tf

 

When i did my compression test w/ Ek9t (tom) i only gave it 5 cranks and read out 190 all across.. my 94 gsr has 65k

 

The numbers aren't off much, so I wouldn't worry too much at this point.

The calibration of the tester may also be off. This explains why I got 230psi in all cylinders..I'm assuming the tester was off, but I know that all cylinders were pumping about the same amount of air.

 

When I did a compression test on my car, it was about 180 across... except on cylinder 2... which was a whopping 160 (that cylinder head is gone now )

 

I wouldn't worry about the #'s.It is more the inconsistany you are looking for.There are a few ways you can go about doing it that would affect the #'s you get.That is really consistant. I would be ok with that.

 

Teken- I just redid the test and I got 160 on all four. The guage just kinda twitched on the first stroke and then on the secound or third jumped right up to about 80, then about 130-140, then went slowly up from there. I then poured one capful of oil into each cylinder and retested. The compression seemed to go up at roughly the same rate, but instead of slowing down at about 140, went strongly to about 160-170 then slowed down. The final numbers were 180 185 190 185. Any ideas? Thanks everyone for the help so far.

 

^^^