Failed my compression test badly

[FourG63 97GST]

Well I was at the shop today, so I did I got compression test while I was at it.
I got 85psi across all four, the minimum should be 133psi. Ill take it back to the shop and check out my pistons and rings on monday.
no newbie replies please, not looking for assumptions. Discuss

 

[CraigB]

If you would do a cylinder leakage test you could find out why.

 

[FourG63 97GST]

any other problem/info I can get from the test?

 

[psi-plz]

i once checked compression on an ej25 subaru motor for a customer, and got about 50-60 psi no one cylinder. after taking the motor out and the heads off we found a very burned/ broken valve. it had actually chipped about an 1/8" off one side. i don't know how likely it would be for this to happen on a dsm motor, but it would be something to consider.

 

[t3t4dsm]

do a leakdown first .that way you can check for head gasket damage ...

 

[DSMJim]

Did you do the test with the motor hot or cold. You will get different reading depending. Also after the motor is cold, pour a little oil down the spark plug hole and redo the test and see what happens..

 

[AWDkitkat]

Its odd you got 85 on all 4. Im sure if you pured a cap full of oil in each comp would still be low. My guess is blown hg or you bent a set of valves. have you jumped time or over heated? water in the oil? smoke? ruff idle?

 

[FourG63 97GST]

Originally posted by AWDkitkat
Its odd you got 85 on all 4. Im sure if you pured a cap full of oil in each comp would still be low. My guess is blown hg or you bent a set of valves. have you jumped time or over heated? water in the oil? smoke? ruff idle?

well the car was cold. an If I blown a hg, or bent a valve I dont think the car will drive. right? an It still pulls hard. idling fine too.

so Ill redo the compression and do that leak down test and see what the result it.

I also heard that I need to take one spark out at a time to do the test on that cylinder, I tooked them all out then test every cylinder with all the plugs out.

 

[Lucky13]

I believe the Vfaq says to pull them all at the same time.

 

[scorpion]

It doesn't matter if you take them all out or just one if turning the crank by hand. If you want to just crank the motor over with the starter, then I would say definatly remove all, though you may flood the enigine that way. I always turn engines over by hand when doing compression tests so I'm not sure.

 

[MikeL]

Originally posted by scorpion
It doesn't matter if you take them all out or just one if turning the crank by hand. If you want to just crank the motor over with the starter, then I would say definatly remove all, though you may flood the enigine that way. I always turn engines over by hand when doing compression tests so I'm not sure.

Try another gauge, most of the time, a car needs 110psi to even start, if the car is running fine you may just have a bad gauge. At the SO last year a friend of mine borrowed someones gauge, and it was showing 120psi, he freaked, then I got my gauge just to be sure, and he had his previous 165..

 

[AWDkitkat]

I would try another guage also. just seems odd to have 85 on all 4 and still pull hard. should pull like a civic
BTW a car will drive with bent valves (if not to bad) and hg.

 

[Ricardo]

hey Agim sorry to hear that but 84 is real bad man, the numbers don't seem to be accurate, when I did compression test on mine after running lean and burning down pistons/valves/head gasket, 3 cylinder were around 100 and the cylinder where piston no.2 (burned/chipped) was obviously had 0 compression. So if you got 84 on all of them is because there's something really wrong going on your engine or a innacurate readings. I'll give you a call sometime soon maybe you want to come down my shop to check it out.

 

[Ricardo]

alright problem solved, it was a bad reading we got 150 all across.

 

[FourG63 97GST]

^^^ beat me to it. got 150

 

[DSMJim]

If you drop a compression tested even once it will knock it out of accuracy and cause crap like that..

good way to soil yourself...

 

[ModInProgress]

I agree with awdkitkat. i would say its something in the valve train because its extremely odd to have all four the same low psi with out it having to be the valves or a lose head.. ya maybe check the torque on teh head i thinks supposed to be like 75,,, or i would say you jumpeds some teeth on the cam gears.

 

[FASTSPOOLINGST]

i know this thread is over a year old, but if some of you guys are still around, i can use your suggestions and knowledge. I just did a compression test today, due to some smoking problems i had after i did a head gasket change. I just bought the gauge/tester today and as soon as i got back i did the test. As you are looking at the engine, this is what i got.

80 135 145 73

This was with the motor cold however, but the outer cylinders are still low as hell.

I changed my oil after the test, just to see if there was coolant in it and NO there was no water/coolant in the oil i drained out.
There is not a mess around my engine bay like there is a hg leak either. I can't figure it out.

Also, the plugs are brand new and when i pulled them, they were looking good, i nice grey on them, there were no oil deposits on them.

 

[CanadianTSi]

Originally posted by FASTSPOOLINGST


This was with the motor cold however

Do another test with the motor fully warmed up.

On a side note, my motor has 205,000 km's and I have 180 across all four

 

[FourG63 97GST]

as this was brought back
I did another test like 2 weeks ago
got 174-180 across all four
I guess the other tester had a flaw

 

[Defiant]

Originally posted by scorpion
I always turn engines over by hand when doing compression tests so I'm not sure.

How odd to me. I've never heard of doing a compression test that way.

 

[DSMJim]

Originally posted by FASTSPOOLINGST
i know this thread is over a year old, but if some of you guys are still around, i can use your suggestions and knowledge.

Yeah this is an old one to drag back from the dead. Glad it was another case of the tester malfunctioning. Seems that a lot of people do this and get upset before trying a new tester.

People, BUY your OWN tester and keep it safe, then you need not worry when you test and get wierd results (well not wory about the compression tester that is)

Oh yeah BTW:

 

[Blitzdeclipse96]

Ok maybe you guys can help me i go out to my car this morning and go to start it....all it does is try to turn over but no start. I did have a small leak in the water pump and it may have ran hot once. So i run a compression test and all across the board i get 0 thats pretty bad.....any help is appreciated.
Chris

 

[FASTSPOOLINGST]

no helping you. You either did it wrong or you blew a head gasket. All four cylinders being bad, that seems odd. Are you sure you did it correctly. Is your engine bay, at least the lower half of it flooded with oil? Do you still have coolant? Drain it and check for oil in it.
If you don't have a big ass puddle of oil under your car, then you must have did the test wrong. I had low compression on 2 cylinders and still had puddles under my car right below the two bad cylinders.

 

[Blitzdeclipse96]

Hey ok....had a guy come out and do the test.....he says all cylinders were bad...0 compression. Is this possible? How is this test to be administered? He had me get in the car and press the clutch in and crank it..Could the guy have been screwing me? How can i check this myself and the right way...can someone give me a HOW TO on it?
Chris