I did a compression test on my Del Sol dohc vtec. . It was 180 all across. But, I did not remove the relay or did the full throttle. If done again would I expect to see higher numbers?

 

That sounds about right. You shouldn't go full throttle when doing a compression test, I think it should go to about 2000 rpm or 2,500 i cant remember but you actually lose compression when rpm increases due to the fact that the valves stay open shorter and there is less air to compress.So your reading will actually drop at higher rpm.

 

dude are u actually saying u think u can test compression with a car running!! I surely hope not

 

Yeah u can check compression with the car running. Its called a running compression test. You migh be thinking of a leak down test. Thats a whole different thing when you put the piston at tdc on the compression stroke and check if there are any leaks by putting compessed air where the sprk plug goes. Look it up dude.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2004es2 &raquo;</TD></TR><TR><TD CLASS="quote">Yeah u can check compression with the car running. Its called a running compression test. You migh be thinking of a leak down test. Thats a whole different thing when you put the piston at tdc on the compression stroke and check if there are any leaks by putting compessed air where the sprk plug goes. Look it up dude. </TD></TR></TABLE>
Are you retarded?? A compression test should be done with the car not running, just take out the spark plug wires and crank the car over a couple of times on full throttle to get accurate numbers.

 

I agree, A compression test is done with the ignition off disconnected and throttle open.

I did the same mistake as you and forgot to step on the peddle...still have to do it again to see what the difference is.

Make sure to kill your ignition when you do it next time.

 

Ok first there are 2 compression tests you could do. 1.) a static compression test, which is the one you are talking about where you hook it up and crank it 6-10 times and blah blah and 2.) A running(dynamic) compression test where you take out one spark plug at a time and hook up the kit, ground the spark plug wire and remove the injector clip for the cyl. you are testing. Then start the car, take the reading at idle then increase to 2000rpm and take that reading. There you just learned something. If you don't agree search it on google or something. I've done it many times and it is as accurate or more accurate than a static compression test. Now lets be friends. LOL

 

I just take the plug off the distributor when i do mine.

 

Yeah that is the quickest way to do it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">
Are you retarded?? A compression test should be done with the car not running, just take out the spark plug wires and crank the car over a couple of times on full throttle to get accurate numbers. </TD></TR></TABLE>

dude i am with you, sounds retarded. in all the manuals and books ive read on hondas i have never seen nor heard of someone doing a test with the car running. and i wouldnt take the chance

 

I guess it might sound strange but when the car is running it better simulates drivig condition which gives you a more accurate test. Anyway the main purpose of a compression test is to see if there are equal readings across all cylinders and the op has that. If he had a leak a leakdown test would be done to identify where the leak is coming from. Have ay of you guys searched for the running compression test?

 

. <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2004es2 &raquo;</TD></TR><TR><TD CLASS="quote">Ok first there are 2 compression tests you could do. 1.) a static compression test, which is the one you are talking about where you hook it up and crank it 6-10 times and blah blah and 2.) A running(dynamic) compression test where you take out one spark plug at a time and hook up the kit, ground the spark plug wire and remove the injector clip for the cyl. you are testing. Then start the car, take the reading at idle then increase to 2000rpm and take that reading. </TD></TR></TABLE>


He's right. The service consult at my shop says the same thing.I thought it was weird too, until I saw you take out the plug and pull the injector for the cylinder you're testing.

 

u need to remove the ecu fuse and take out all the spark plugs in order to do a compression test. if your car is running. then you get 180 psi all cross. i wonder how ?

 

Yeah for a static test you do.

 

popcorn anyone?

 

If you pulled the injector while the car is running wouldnt you lean out that cylinder?

 

http://www.imperialclub.com/Re...c.htm

Read that.

Basically you do a compression check for numersous reasons, mainly loss of power. A static compression test indicates if it is a mechanical problem IE Pistons, rings, Head Gasket, Stuck Valve, bent valve (You get the point).

Static will ALWAYS be higher than Dynamic.

A dynamic test is only done when a static test comes back with good results, but there is still a loss of power. Then you move on to the dynamic test to further investigate the issue.

I wouldn't recommend a dynamic test unless you have honestly ruled out everything and cannot figure out the loss of power (or the issue). Dynamic testing may/may not be good on your engine (firing off all buy 1 cylinder really isn't good on an engine, due to balance issues, yada yada yada.)


If you are withing 5-10 PSI across the board I wouldn't even think twice about it.

Just do a static. Number values mean nothing!

Yes it will lean your cylinder out, theres no fuel! but what does it matter that its lean if theres no spark? Your not firing the cylinder your testing. Not firing a cylinder is not bad on anything but the rotating assembly.

 

Notice how it says 250rpm and WOT. Your car doesn't idle at 250rpm.

Also, pull the ECU fuse when you perform the test. That will disable spark and fuel. If you don't disable spark, you can blow the coil (by just removing the spark plug wires). I learned the hard way.

EDIT: This chart is for a d16z6, but 180 across the board is good for your engine too.

 

Thank you all for your replies and input. I will try this again on sunday if it's not to cold outside. This time I'll to it the right way.
on me for not doing it right the first time.