Just did my first ever compression test, and my first test on my newly rebuilt motor. Things were going smoothly, until cylinder 4. cranked it over, and at about the 6 or 7th crank, there was a loud "POP!" of course I was like I thought maybe the hose on the tester blew. hose checked out ok. So naturally I give it another shot to see if happens again. Crank it, and on the first crank, does the same POP! noise. OK now Im ready to break something because whatever it is doesnt sound good. So I figure 3rd times the charm(if its broken, might as well break it all the way haha), try it one more time, this time no POP! sound. Phew! Not sure what it was but it was strange.

Anyway, it was kind of difficult to tell what my numbers were. It seemed to just keep going up and up with each crank and I know you are supposed to stop around 5-7 cranks. It was hard to get an exact reading, but for the most part it appeared to be anywhere from 270-290 or so across the board, so it would appear that my compression is OK and rather healthy.

Any thoughts on what the POP! sound was?

 

It used to do that when I did compression tests on my motor every once in a while. Not sure why, it might just be something in the tester. There was nothing wrong with the motor, so I am assuming its just something that "happens" every once in a while with certain testers. Good numbers though

 

"pop" is fine.

 

Did j00 disconnect the ECU? Or removed the ECU fuse? Or disconnected the fuel injectors?

 

for compression test?

just remove ecu fuse, jump service connector and go....

 

just removed the fuse. I put everything back together and it seems to be fine.

 

I also have had the "POP", it is normal. I have done it on different cars and there is always a "POP" sound....so im assuming it is the tester. probably the guage when the pistons start to compress.

270-290...what do you have in the motor?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Art Vandeleigh &raquo;</TD></TR><TR><TD CLASS="quote">
270-290...what do you have in the motor? </TD></TR></TABLE>

Stock LS

 

i never had mine pop, i just disco the Dist plug. and go to town

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Soup **** &raquo;</TD></TR><TR><TD CLASS="quote">for compression test?

just remove ecu fuse, jump service connector and go....</TD></TR></TABLE>

Why does the service connector need to be jumped?

 

270-290 on a stock LS motor? You've got a strong one there


Modified by JMU1337 at 1:44 PM 7/21/2003

 

lol.