compression test on my 01 MP3 *worried*
 

im kinda worried b/c i talked to mazda and they said it should be around 150 to 175 well mine fell way short and i dont know when the maintanace should be taken into consideration when ur compression is low mine is at 120 across all 4 cylinders and was wondering what everyone else has gotten on their cars when they did compression tests i have 65000 miles on my car and i dont think this is right for this low of a compression please HELP!!!

hmmm..compression is even across all cylinders ??? I'm guessing error in testing...try putting a little oil down in the cylinder and try again and see if the number shoots up

puttin oil into the cylinders would defeat the purpose of doing a compression check were as if your rings are bad ur compression would be low you put oil in it will somewhat seal the possible bad rings and give you a higher compression

when i say even i mean within 2-3 points. it is possible not exactly 120

I merged the two threads together. There is no need to post the same question in two separate forums.

duh !?

It doesnt defeat the purpose. It tells you if your rings are bad. If the numbers DONT shoot up,then youre are doing it wrong or reading the guage incorrect.

And if the numbers are within 2-3 to each other, that IS even.

The reason I posed the question is that it is VERY unlikely all 4 cylinders went bad at the same time

not considered going bad just wore out which is y u lose compression evenly in the first place

Mike is right......it's VERY odd that all 4 would lose a similar amount of compression....especially at 65K miles. Were it me I'd try one can of "RESTORE" junk you can buy from autozone and see what ti does. I used it in one of my older mustangs and I was surprised it actually rebuilt the compression up to a decent level...however I had to keep adding it with every oil change but it kept me driving when nothing else would.

Oh that kind of stuff is horrible, and your right onece you use it you can't stop.

losing 30-40 lbs of compression in 65K miles IS going bad...that isnt even CLOSE to normal wear and tear.....My MX-6 with 146,000 still gets close to 150 across all 4 cylinders....

This is tough because you didn't do a compression check when new. (No baseline to compare to - to determine if it is indeed 'lost'.)

Has it been a gradual loss of power over time or an 'event' that made you check the compression?

All across/even is 'good'. (Not great, but hey, good.)

Manufacturing tolerances give the 'range' of compression - that is why it is not an exact number.

If it eats at ya' - i would say tear it down, re-hone and add bigger pistons. Would it be worth it? I think the $$ to do that would be better spent on a WOMP! ;)

Mf friends old Catalina was losing compression a few weeks ago, so he just hooked up a 200 shot of nitrous. He figured if the compression was lower, FI would bring it back up. The wierd thing is, it worked. The car feels just as strong as it used to when he sprays. I'm just waiting for the rings to completely give out, lol.

no idea what is was before i have no idea what the prevouse owner did to the car either. yes it is possible to lose compression evenly what prolly happened is the oil wasnt changed often. i was plannin on WOMP'g it anywayz and let it go boom but already have another block cleaned up and ready to go no compression changes just rods prolly. and do it that way.. o and no reason on what i was checking it was just checking my plugs and wanted to check the compression as well.. the color on the plugs is perfect not lean or rich so it isnt nething major i will just let it dwindle