compression test ?s

O

opie

Member

:

03 mazdaspeed protege

• Jan 28, 2010

• #1

the car is running like crap wont hardly even pull out idles just fine for a little bit then real erratically also have a little tickin sound coming from the bottom end dont know alot about car but someone told me to do a compression test so i did
on the first cylinder i got 150
on the second 140
then 150 on the third
and 140 again on the last cylinder
first ? is this normal and second does anyone have any ideas on what might be wrong with the car

 

K

Knox Joe

Member

Contributor

:

Ti MSP

• Jan 28, 2010

• #2

Thats low, but not crazy, catastrophic failure low. Your rings may be worn, or a gasket could be leaking. My compression was 185/180/180/185 for a reference point. I think brand new all the cylinders should be around 190-195.

 

O

opie

Member

:

03 mazdaspeed protege

• Jan 28, 2010

• #3

is there anyway to tell which one it is without tearing it all apart to see

 

G

gtrs28

Member

:

msp

• Jan 28, 2010

• #4

opie said:

the car is running like crap wont hardly even pull out idles just fine for a little bit then real erratically also have a little tickin sound coming from the bottom end dont know alot about car but someone told me to do a compression test so i did
on the first cylinder i got 150
on the second 140
then 150 on the third
and 140 again on the last cylinder
first ? is this normal and second does anyone have any ideas on what might be wrong with the car

Click to expand...

how much did they charge you for the test. maybe i need to do a test.

 

O

opie

Member

:

03 mazdaspeed protege

• Jan 28, 2010

• #5

i did it myself i bought the compression kit at advance dont remember how much i payed for it though

 

K

Knox Joe

Member

Contributor

:

Ti MSP

• Jan 28, 2010

• #6

opie said:

is there anyway to tell which one it is without tearing it all apart to see

Click to expand...

That would be a question for someone more knowledgeable than myself. All the cylinders are low, so could be worn rings, or could be a gasket. I don't think there is anyway to check the gaskets, aside from maybe listening for a leak in each location.

gtrs28 said:

how much did they charge you for the test. maybe i need to do a test.

Click to expand...

It's really very easy. you can buy a compression tester at any parts store for a reasonable price. You just pop out each spark plug, one at a time, and check it.

 

Last edited: Jan 28, 2010

X

XoX1de

Member

:

2000 Mazda 626 LX

• Jan 28, 2010

• #7

by doing the compression test make sure u dont use the adapter tube that comes with it, screw the hose directly to the spark plug hole. If you put the adapter tube it WILL show a lower compression level. I did the test before and after, 125psi all across de board vs 205psi.

 

B

BOOSTR

1 OWNR MSP

• Jan 29, 2010

• #8

opie:
How many miles on the car and have you changed your plugs, pcv and air filter. A seafoam treatment may be beneficial as well. Depending ou your mileage so may some new plug wires and or coil packs. Is the operating temperature normal?

Usually there is a min and max compression psi when compression testing. Your numbers suggest less than a 10% difference between cylinders. So that does not indicate a problem unless those figures are in fact accurate and less than the FSDE spec minimum psi. You should do the test again to see what numbers you get.

Your erratic idle and poor running condition could be a result of worn ignition components, dirty filter or a clogged or stuck open pcv.

 

O

opie

Member

:

03 mazdaspeed protege

• Jan 30, 2010

• #9

the car has 119 thousand miles on it i already cleaned the air filter put it new plugs and plug wires i have not tried the pcv or the coils also i just used the hose not the adapter that comes with it
someone also said that one of my rocker arms might have broke so i am goin to take a look there too