Dry compression Results

[-Alero-]

ok so i bought this compression gauge from advanced to see if maybe i can find some different results for my on going problem

now what i read it said to loosen all the spark plugs, but what i did was just remove 1 spark plug and screw in the gauge and leave all the other spark plugs as is. Now im not sure what difference it would make if i loosened all the other spark plugs, but i just gave it a try doing it my way then ill see if the results are different later doing it the suggested way.

yes the car was at operating temp, and yes i screwed the fitting in as far as i could get it. but the results were all over the place..

i had 2 cylinders at about 120 lbs/8-9kpa(x100)

and all the others were random as hell, 1 was 60 lbs/4kpa(x100) another was 90lbs/6.5kpa(x100) and the other 2 were about between 100-110lbs/7kpa(x100) *side note- the gauge also did not drop*

now this could be because of the whole not loosening the other spark plug issue, but i dunno....the car actually tried to idle 5 cylinders at a time.

another thing im noticing is the car starts to missfire under load on the interstate upwards into the 2500-3500rpm range......i noticed some time before and replaced the plugs with AC-Delco iridiums....exactly what the manual calls for. the missifre went away and just now came back and these plugs probably only have about 2k miles on them.

the car still has its rough idle issue, and upon further reading, im guessing i might need to replace my lifters, knowing they have never been replaced before and im almost positive my piston rings are fine.

so as far as the compression loss and the definete missfire on interstae goes, im asking the Guru's here, what are your suggestions/input.

[WhiteV6]

Never pull your spark plugs out of aluminum heads when it is at operating temp. That is a good way to strip threads.

I don't understand your psi and then a kpa reading to go with it. Pull your injector fuses next time so it won't spray fuel or try to run. It sounds like your valves or rings aren't seating well on most of the cylinders. 120 is low and those are your best.

[-Alero-]

yeah but if it were rings, that doesnt explain the missifre......i have no loss of oil, and my plugs done have oil deposit on them

[alerored04]

Sounds somewhat similar but less extreme than my experience with bent valves. Yours may not be closing all the way.

[-Alero-]

or opening all the way? if the valves didnt close all the way would the pressure gauge start to drop? it held pressure....but god damn this is such a stupid headache

[AftermathAlero]

Your not suppose to fire up the car. Your suppose to pull out the injector fuse or fuel pump relay then just crank over the car a few times and look at the highest number.

[-Alero-]

Your not suppose to fire up the car. just crank over the car a few times and look at the highest number.

lol

ok ill do that tommorow

[alerored04]

My gauge never dropped. They hold the pressure so you can do this by yourself and not have someone crank it while you look at the gauge. Mine has a little release button on it that zeros the gauge back out.

[-Alero-]

My gauge never dropped. They hold the pressure so you can do this by yourself and not have someone crank it while you look at the gauge. Mine has a little release button on it that zeros the gauge back out.



right mine too

[Nate's Alero]

so, get a pressure tester, apply pressure to the cylinder, and see how fast/far it drops

[-Alero-]

i cant seem to find a pressure tester, and im not to familiar with how one works

[Nate's Alero]

i cant seem to find a pressure tester, and im not to familiar with how one works

autozone... rent it

[Blktrax]

http://www.actron.com/product_detail.php?pid=16170
http://www.actron.com/xcart/files/d_24_01.jpg

The method to Properly do a compression test:


The method involves using a manual, handheld compression gauge.

1: Make sure the engine has been warmed up before beginning the test, to ensure that the oil has been warmed up. A cold engine will not test correctly.

2: Disable the ignition module or coil.

3: Insert the compression tester into one cylinder spark plug hole at a time.
Hold the throttle to full open position to ensure the engine gets adequate air intake.

4: Crank the engine continually for at least five to 10 full revolutions to obtain an accurate reading on the compression tester.

5: Record the reading for each cylinder.

If any cylinders vary 10 percent or more from each other a problem may exist in one or more cylinders. If the variance is greater than 10 percent, specialized testing equipment may be required to fully diagnose the problem.
If all cylinder readings are within 10 percent of each other, no further testing is required and compression is considered optimal.

Link to the manual:
http://www.actron.com/publish/2004/06/16/pdf_english_16170.pdf

[-Alero-]

that's exactly what i have.....

[Blktrax]

ok good, and totaly not trying to be an a-hole, have you done the procedure as above or in the manual?

What are the results?

[-Alero-]

stil havent had the time to do the manual procedure but i did everything just never pulled ignition control fuse or injector fuse.

i should have something by sunday, since i have to drive to delaware tommorow.........just wish the topend would just impload so i could point at the dealer and say "hey look theres nothing wrong with my engine just like you said"

[Blktrax]

Drop it in 1st and mat it.

Its a cast block, the aluminum is gonna give.

[-Alero-]

lol sounds like fun