We did a compression test yesterday and the results were:

cyl 1- 110
cyl 2- 110
cyl 3- 118
cyl 4- 120

Oh Yeah...Its a Boosted R...Just needed some info on what else except for rings it could be

 

Did you do the test right?

 

Those are way low.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by walker111 &raquo;</TD></TR><TR><TD CLASS="quote">Did you do the test right?</TD></TR></TABLE>

 

thats definitly your rings taking a **** on you. do a leakdown test to see if thehead gasket and valve seals are a part of the problem as well

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jh &raquo;</TD></TR><TR><TD CLASS="quote">We did a compression test yesterday and the results were:

cyl 1- 110
cyl 2- 110
cyl 3- 118
cyl 4- 120

Oh Yeah...Its a Boosted R...Just needed some info on what else except for rings it could be</TD></TR></TABLE>

did you do the test with the engine warm and the throttle open?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by projectTeG &raquo;</TD></TR><TR><TD CLASS="quote">did you do the test with the engine warm and the throttle open?</TD></TR></TABLE>

Beat me to it. I'm guessing the throttle was closed.

Engine temps need to be somewhat close to operating temps, and the throttle need to be WOT.

Since the numbers are very close to eachother, I do not suspect there is a problem, but rather your procedure in doing the compression test.

 

I guess i did the test right..Why would you need the trottle open?

 

lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jh &raquo;</TD></TR><TR><TD CLASS="quote">I guess i did the test right..Why would you need the trottle open? </TD></TR></TABLE>

That is how you perform a compression test. You keep the throttle at 100% open and perform the test when the engine is at a near operating temperature. The numbers are not right unless you perform the test under the above circumstances.

 

http://www.c-speedracing.com/h...t.php

 

update: 150 all across....with the trottle open and distributor unplugged: (should it be?)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jh &raquo;</TD></TR><TR><TD CLASS="quote">update: 150 all across....with the trottle open and distributor unplugged: (should it be?)</TD></TR></TABLE>

yes the distributor and ecu fuse should be unplugged. if you dont unplug the dizzy you can fry your ignition coil. he ecu fuse stops fuel from getting injected into the cylinders.

 

Couldnt you just pull the harness plug near the brake master cylinder?

 

I understand about the throttle being open, and why you wouldnt want fuel, but the ignition coil thing I don't understand. Why is the coil at risk during a compression test?
What is the correct way to say, check for spark?
Wouldn't you at that point be turning the engine over with the plug wires disconnected from the spark plugs? How is that really any different?
Someone please enlighten me...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs &raquo;</TD></TR><TR><TD CLASS="quote">Couldnt you just pull the harness plug near the brake master cylinder?</TD></TR></TABLE>

I've always thought about that but never tried it.

 

If you want, we can do another compression test at my place on Saturday. Those numbers seem very low...

 

what time?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by andyt &raquo;</TD></TR><TR><TD CLASS="quote">I understand about the throttle being open, and why you wouldnt want fuel, but the ignition coil thing I don't understand. Why is the coil at risk during a compression test?
What is the correct way to say, check for spark?
Wouldn't you at that point be turning the engine over with the plug wires disconnected from the spark plugs? How is that really any different?
Someone please enlighten me...</TD></TR></TABLE>

in a nut shell because when the plugs are out of the head and the wire boot....meaning you have open plug wires....there is no where for the spark to discharge causing the coil to be damaged.

 

It will most likely discharge and ignite something in the engine compartment. Especially if the fuel isn't disabled. Or if there are vapors.

 

Ok lets review for a second.
(I still don't understand...)
Electricity flows from the battery to the ignition coil, which acts as a transformer, generating a large burst of energy which goes into the distriibutor and is disbursed through the rotor to each plug in time. Now, if it doesnt jump the gap, where does it go? Your telling me it goes back to the rotor, back through the dizzy into the coil and shorts it out??

 

let someone whos done a compression testbefore help you out man. As long as they are even across the board I will have to agree and say that your just doing it wrong and everything is most likely ok.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by migs &raquo;</TD></TR><TR><TD CLASS="quote">Couldnt you just pull the harness plug near the brake master cylinder?</TD></TR></TABLE>

i thknk it woul just ve easier to unplug the dizzy and pop the fuse if you ask me.<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by andyt &raquo;</TD></TR><TR><TD CLASS="quote">Ok lets review for a second.
(I still don't understand...)
Electricity flows from the battery to the ignition coil, which acts as a transformer, generating a large burst of energy which goes into the distriibutor and is disbursed through the rotor to each plug in time. Now, if it doesnt jump the gap, where does it go? Your telling me it goes back to the rotor, back through the dizzy into the coil and shorts it out?? </TD></TR></TABLE><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by andyt &raquo;</TD></TR><TR><TD CLASS="quote">I understand about the throttle being open, and why you wouldnt want fuel, but the ignition coil thing I don't understand. Why is the coil at risk during a compression test?
What is the correct way to say, check for spark?
Wouldn't you at that point be turning the engine over with the plug wires disconnected from the spark plugs? How is that really any different?
Someone please enlighten me...</TD></TR></TABLE>

it wont be able to discharge its energy, basically like looping a wire back into a battery.