Got my car compression tested... look inside for results, What do I do?

[vr4gasmtt]

177 130 130 175

I heard that its okay if the numbers a little low, just as long as they were constant... well my results definatly isnt constant. Whats wrong with my car? its a 99 GSX 179k.

It feels kind of weak, I thought that was a boost leak which i havent done yet. But boost doesn't kick in til like 3500rpm.

Any feedback would be nice.
J

 

[2gGSX]

Try pouring a cap-full of oil into the spark plug wells of 2 and 3 then do the compression test to see if the numbers improve. If so, then rings are going out. Otherwise, a leakdown test will give us much more information.

 

[92awddsm]

177 130 130 175

I heard that its okay if the numbers a little low, just as long as they were constant... well my results definatly isnt constant. Whats wrong with my car? its a 99 GSX 179k.

It feels kind of weak, I thought that was a boost leak which i havent done yet. But boost doesn't kick in til like 3500rpm.

Any feedback would be nice.
J

Try adding oil to the 2 low cylinders and see if the compression comes up. If so, more than likely it is worn rings. If not, it might be a blown hg leaking between #2 and 3 cylinders. Also, try a leakdown test and see where the air is escaping from.

 

[vr4gasmtt]

Sorry for sounding like a noob, but... how do I add oil to any of the cylinders?

 

[MrBoxx]

Through the spark plug hole. As stated, add a cap-full and do another compression test immediately after. Report back the results.

Cylinders 2 and 3 are actually slightly beyond the service limit as it stands (130 being service limit on a 2g), but 1 and 4 are amazingly good.

 

[force-fed]

pull plugs 2 and 3, get the oil in there.

 

[vr4gasmtt]

wait, so I put motor oil in there? wouldnt that soak up the spark plugs?

Sorry for sounding like a complete noob, but im completely clueless.

 

[MrBoxx]

A compression tester is a tool that screws into the spark plug threads. The spark plug is not in the cylinder during the test. The oil that you pour in after you do the first (dry) compression test is to see if the oil will seal up the rings and give you better compression. If so, that means that your rings may need to be replaced as well as other service to the cylinder walls if necessary.

Here is the compression test vfaq for future reference. Also read the leakdown test vfaq, since that's sometimes done after a compression test to further determine what needs to be done. It's a little more involved than a compression test but may be useful in figuring out what you need to replace, if anything.

 

[oldman]

wait, so I put motor oil in there? wouldnt that soak up the spark plugs?

Sorry for sounding like a complete noob, but im completely clueless.

1. Remove the spark plug.

2. Pour a capful (small cap not the new Mobile1 caps) of oil into the cylinder.

3. Screw in the compression tester.

Did you do the compression test yourself?

 

[Lunch_Box]

Pull the spark plugs, put a cap full of motor oil in each cylinder, and redo a compression check on those cylinders. Then come back on here and report the new numbers for cylinder 2 and 3.