DISI Compression Results

[802MS3]

Originally Posted by Fullmetal sorry but may i point out all compression and tdc and valve clearance measures should be taking at cold and heated to get true comparisons. cold engines will show true wear cause as metal heats it expands. that is basic metallurgy, cause you might have great starting compression when warm. this may not be true for cold engines and i have seen many cold engine running problems! if you have cold engine running problems this will effect you warm engine closed loop operation. since the computer learns how to get the engine hot it thinks once the engines hot i can start pulling timing and allow for more emission control. this causes lean conditions which will raise the leaning out of engines to increase proper burn and near zero emissions thank you to the federal gov't. And now one key thing to remember is that taking non running compression will not give you true compression number. your compression may drop once you induce fuel into the cylinders, from the fact that most liquid takes more to compress and if you have any type of bend in the rod or cylinder leakage do to higher dynamic compression you can not tell this at @ 700-800 rpm cranking compression test. this test is mainly used to find blown or warped heads. running compression will net you more info. plus you must compare your cold vs hot reading to tell of true cylinder problems. also you need to check your valve lash to see if your running problems are not to to improper valve seating. high cylinder temps can cause valve seats and stem seals to morph allowing more cylinder problems not able to be told by a cranking compression test. load will always affect cylinder pressure along with engine temp. this is why the ecu has complex fuel and load tables based on a very complex algorithm of up to 8- 10 different sensor readings. and it uses an average of cold verse hot to tell which is the most economical and efficient way to use the engine. just my two cents. years of diagnosing all engine types and running problems i will follow what i have learned based on what i read. Always do cylinder leak down test.

haha dude very good info. you coulda spaced it out more and made it a little more easy to follow, but there is a lot of info.

so basically, get a good comparison between cold and warm?

[djuosnteisn]

That post made me cold and warm at the same time.

[aaronc7]

Got a gauge last night... gonna test mine tomorrow. Kinda scared lol. I smoke and stuff, but only at idle and I am catless.... but I am also still making power- last 1/4 mile run I trapped 109 with a passenger in the car. I guess we'll let the results speak for themselves. Will also be doing work on another speed, hopefully we can test his too to compare to mine. A third guy will be there and has a new motor in his car...maybe even get him to test his so we can see what a "new" motor should have.

[Dano]

did this a few weeks ago when I thought I heard a knock at idle but it turned out to be nothing.

Cold motor-none of the suggestions used like cluth and accl pedal depressed. Just cranked her over with injector fuze pulled until PSI hit max...took about 4 compression strokes.

28K miles

1=175
2=174
3=175
4=175

Edit: 400 ASL

[aaronc7]

do you pull out all the spark plugs, and then go thru and hook up the gauge to each cylinder. or pull one plug... check that one, then put it back in, pull the next plug, test that one, etc etc?

the instructions say to pull all initially, just wanted to see what you guys did, it probably won't matter anyways.

[djuosnteisn]

Pull all of them, cause it lets the motor turn over easier.


My take on the cold compression readings is that, why would i care what they are cold? So many things happen when a motor is warmed up, like ring expansions, oil control, etc etc. I think a warmed up comp test is all that matters.

[aaronc7]

thanks. say some prayers for aaronc7's car tonight. kthx

[Lex]

Been waiting for your results Aaron, good luck! and remember to crank until the needle no longer goes up.

[Mizzle]

Originally Posted by djuosnteisn Pull all of them, cause it lets the motor turn over easier. My take on the cold compression readings is that, why would i care what they are cold? So many things happen when a motor is warmed up, like ring expansions, oil control, etc etc. I think a warmed up comp test is all that matters.

"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."

- How to Check Your Engine's Compression - - Search Auto Parts | Automotive News

I'd also like to second the fact that you need to do a leak-down test to see if you have small problems. If you leak too much, put a little SAE30 into the cylinder. If it still leaks down, it's a valve problem and not rings.

[Dano]

ahem...i haz TMIC.....kinda hard to comp test with engine warm..... I pulled all plugs as DJ said the engine turns over faster.

400ASL

[djuosnteisn]

Warm it up before hand. Just go for a nice ten minute stroll lol, then pull the IC and comp check!

[Dano]

IIRC that's about what I did as I am always impatient to get started and just got back from Advanced Auto with shiny new comp guage ;-)

[Lex]

Originally Posted by aaronc7 thanks. say some prayers for aaronc7's car tonight. kthx

Dammit Aaron - don't keep me hanging. I feed off this stuff

[aaronc7]

meh...no good.

like others have said i think consistency is more important that values itself due to atmospheric and eqipment variations. but with that said #2 is low for me. which totally throws me off cuz #3 spark plugs always look the worst and #2 is just like the others.

160
145
165
155

might call off my protune, not sure what i wanna do yet

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[gsrtype1]

not that bad man with 60k... Very reasonable.

[aaronc7]

yeah i guess i should add 65k miles...fully bolted stock turbo. had stage 2 mods within 6000 miles. at around 1000 asl

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[802MS3]

go through with the protune, should be interesting to see any better results.

180, 178, 12, ,179

does my cylinder 3 seem a little low?

[Lex]

Originally Posted by aaronc7 meh...no good. like others have said i think consistency is more important that values itself due to atmospheric and eqipment variations. but with that said #2 is low for me. which totally throws me off cuz #3 spark plugs always look the worst and #2 is just like the others. 160 145 165 155 might call off my protune, not sure what i wanna do yet Sent from my Droid using Tapatalk

Did you throw some oil in to see if it's a leak issue and make sure #2 isn't somehow "shorter"? On these engines even the valves seal poorly due to the carbon buildup.

The numbers themselves are not that bad - what altitude you at?

Originally Posted by 18psiWhiteMS3 180, 178, 12, ,179 does my cylinder 3 seem a little low?

12? wtf?

[Qwik6]

You guys have me scared to do mine. 72k miles and have been running over 18psi for almost 2 years. This shouldn't take a second hand should it? Just hook it up and crank the car over a few times. Should hold the max right?

[aaronc7]

meh...no good. like others have said i think consistency is more important that values itself due to atmospheric and eqipment variations. but with Did you throw some oil in to see if it's a leak issue and make sure #2 isn't somehow "shorter"? On these engines even the valves seal poorly due to the carbon buildup. The numbers themselves are not that bad - what altitude you at? 180, 178, 12, ,179 does my cylinder 3 seem a little low? 12? wtf?

some friends and i spent 10 hours yesterday working on cars..did my comp test at the very end, so the oil thing slipped my mind till right after. i am going to do it all again just to check for consistency, try adding a little oil, and am gonna test another ms3, low miles, intake only- for comparison

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i was jk, I never did a compression test. 12 would be like No rings or something.

[Lex]

Originally Posted by Qwik6 You guys have me scared to do mine. 72k miles and have been running over 18psi for almost 2 years. This shouldn't take a second hand should it? Just hook it up and crank the car over a few times. Should hold the max right?

Nope, the gauge holds the peak value each compression stroke. So hold the gas and clutch in, crank, and go over to the engine and check.

[Qwik6]

So gas and clutch in. What about a fuse?

[aaronc7]

Pull all plugs... connect gauge to one cylinder. turn car on. push ghes and clutch all the way in...crank until the gauge is not rising anymore. you can have a friend check it or set it so you can see it from inside the car, then read the number, release the pressure in the gauge to reset it...and repeat.

My battery sucks so I hooked up jumper cables to another run that was idling while I did it. Or hook up a battery charger or something.

[shpankey]

Dry test: 130, 130, 130, 130

Wet test: 150, 150, 150, 150

13k miles. 2009 MS3 GT

SRI, TIP, HPFP, BPV, RMM

Yeah I know. I'm screwed.

Car runs fine but I felt a dramatic loss in power late last December 09 when I installed these 3 mods: HPFP, ITV22's, Cobb TIP. A guy on another forum said this to me about it...

I notice you have fouled plugs, that may explain your loss of power and backfiring. The fouling may be due to your aftermarket high pressure fuel pump. I suspect the MS3 uses a non-return fuel delivery system for direct injection, and the fuel pressure regulator is located in the fuel tank. If the new pump increases pressure so much that the regulator is constantly in bypass mode, you may be running very rich.

...which I have no idea if it's true. Though I will say that even though the car always ran rich, it definitely ran much richer after the HPFP. I'm going back to stock this weekend and will test again later. I'm at a loss though.

[aaronc7]

if its that consistent you're probably good to go and just how the gauge reads

[shpankey]

I would think the same thing if it wasn't for the 20 psi raise across the board on the wet test.

Someone mentioned to me it could be the VVT. So I'm looking into that but not holding out a lot of hope. Sucks too cause I just spent a bunch of money on a new Meth kit mod.

[Lex]

The wet test seems quite "low" as well so the gauge is probably reading low.

Originally Posted by shpankey Dry test: 130, 130, 130, 130 Wet test: 150, 150, 150, 150 13k miles. 2009 MS3 GT SRI, TIP, HPFP, BPV, RMM Yeah I know. I'm screwed. Car runs fine but I felt a dramatic loss in power late last December 09 when I installed these 3 mods: HPFP, ITV22's, Cobb TIP. A guy on another forum said this to me about it... ...which I have no idea if it's true. Though I will say that even though the car always ran rich, it definitely ran much richer after the HPFP. I'm going back to stock this weekend and will test again later. I'm at a loss though.

[Frequentflyer]

Originally Posted by shpankey Dry test: 130, 130, 130, 130 Wet test: 150, 150, 150, 150 13k miles. 2009 MS3 GT SRI, TIP, HPFP, BPV, RMM Yeah I know. I'm screwed. Car runs fine but I felt a dramatic loss in power late last December 09 when I installed these 3 mods: HPFP, ITV22's, Cobb TIP. A guy on another forum said this to me about it... ...which I have no idea if it's true. Though I will say that even though the car always ran rich, it definitely ran much richer after the HPFP. I'm going back to stock this weekend and will test again later. I'm at a loss though.

I highly doubt your rings are that consistently worn perfectly across the board and is your cause of lost power.

[shpankey]

About the HPFP... this was said to me...

Higher pressure is not a good idea as its going to make the engine richer without tuning. Higher volume is OK but higher pressure is a bad idea. Considering the results of the wet test you should also do a leakdown test to determine how much leakdown you have. It's possible that the excess fuel washed the oil off the cylinder walls and damaged your piston rings.

...does that hold water? I have to admit that my power loss did come after I installed that.

[Frequentflyer]

Lots of people have installed aftermarket HPFP's without reporting a loss of power. I installed one a few weeks ago and if anything, the car feels stronger. High pressure is essential for overcoming the pressures within the cylinder to provide proper atomization of the fuel. How much fuel depends on how long the injectors stay open for and if the O2 sensors are doing their jobs, the ECU should adjust injector duty cycle to maintain the appropriate AFR. So do I think you're running rich because of a new pump? No. This car runs way rich from factory to begin with.

[cpolly69]

Originally Posted by Frequentflyer Lots of people have installed aftermarket HPFP's without reporting a loss of power. I installed one a few weeks ago and if anything, the car feels stronger. High pressure is essential for overcoming the pressures within the cylinder to provide proper atomization of the fuel. How much fuel depends on how long the injectors stay open for and if the O2 sensors are doing their jobs, the ECU should adjust injector duty cycle to maintain the appropriate AFR. So do I think you're running rich because of a new pump? No. This car runs way rich from factory to begin with.

i agree with this - i think for all the breather mods everyone likes to slap on the ms3, an aftermarket cdfp & a few negative numbers in the fp table on the standback could do everyone a bit of good...

[djuosnteisn]

Wow aaron, not earth shattering bad, but not exactly optimal either.

Have you had any other dip stick issues recently?

[cpolly69]

aaron - i kinda called this a while back if you remember when i sold you that used k04

btw guys something to keep in mind - if you are leaking compression out of your piston rings or out your valve guide seals - 2 things will be happening

1. your pcv will be even more messed up then normal - compression gases and pressures in places where they shouldn't be screws up the flow of lots of stuff -
a good indication of this (at least with the stock pcv setup) is seeing crud coming back out of the port on the valve cover that leads to your turbo intake -
when my motor was on it's way to death i had lots of crud in this area - at points so bad it was getting on my maf
2. you will be burning oil - i was up to about a quart every 200 miles when i started the battle for a new motor with my dealer - the amount that gets squeezed out via pcv imbalance should be minimal - if you notice more, you've got an issue
the day i actually took my car in i was bellowing smoke

if you have the other leak of compression (head gasket) you will most likely see increased ect - well above 220 - but hell the other things i'm saying here will cause that too

[aaronc7]

Originally Posted by djuosnteisn Wow aaron, not earth shattering bad, but not exactly optimal either. Have you had any other dip stick issues recently?

nope none at all

Originally Posted by cpolly69 aaron - i kinda called this a while back if you remember when i sold you that used k04 btw guys something to keep in mind - if you are leaking compression out of your piston rings or out your valve guide seals - 2 things will be happening 1. your pcv will be even more messed up then normal - compression gases and pressures in places where they shouldn't be screws up the flow of lots of stuff - a good indication of this (at least with the stock pcv setup) is seeing crud coming back out of the port on the valve cover that leads to your turbo intake - when my motor was on it's way to death i had lots of crud in this area - at points so bad it was getting on my maf 2. you will be burning oil - i was up to about a quart every 200 miles when i started the battle for a new motor with my dealer - the amount that gets squeezed out via pcv imbalance should be minimal - if you notice more, you've got an issue the day i actually took my car in i was bellowing smoke if you have the other leak of compression (head gasket) you will most likely see increased ect - well above 220 - but hell the other things i'm saying here will cause that too

yeah that is probably me. i lose a little oil over time but nothing crazy like 1 qt every 200 miles. ive had some stuff come thru the intake for quite awhile, even before i had most of the mods. I dont know if its just some coincidence or what, but either way ill prob be taking it easier on the car and/or mods... i'm not totally against building the engine, but i really dont have time to mess with that now.

[djuosnteisn]

Build your motor and compliment your bolt-ons with a shiny new big turbo

[Lex]

Lots of smoke has also meant a bent rod. If the rod is bent and piston is traveling off centre from the bore, the rings won't seal well and you'll have lots of smoke.

Cpolly is correct, a lot of guys battling lots of smoke are probably leaking compression.

Aaron, your car has been like this for some time now and a lot of MS3s are. I remember way back in the day when you had oil in your intake.

Cpolly, did you ever figure out what caused your loss of compression? Was it rings or was it valves?

A lot of the gunk we get on the intake valves can prevent them from sealing.

Also, DI is notorious for being bad on the bore since it sprays fuel right against it and washes off oil film. If an oil squirter is partially plugged or oil control rings are blocked/fail that bore loses a lot of lubrications and wears down considerably faster. If an injector gets stuck open or overfuels it's game over as well.

IMO high quality synthetic is a must in this car from day 1 after seeing enough internals on these cars.

[cpolly69]

Originally Posted by Lex Lots of smoke has also meant a bent rod. If the rod is bent and piston is traveling off centre from the bore, the rings won't seal well and you'll have lots of smoke. Cpolly is correct, a lot of guys battling lots of smoke are probably leaking compression. Aaron, your car has been like this for some time now and a lot of MS3s are. I remember way back in the day when you had oil in your intake. Cpolly, did you ever figure out what caused your loss of compression? Was it rings or was it valves? A lot of the gunk we get on the intake valves can prevent them from sealing. Also, DI is notorious for being bad on the bore since it sprays fuel right against it and washes off oil film. If an oil squirter is partially plugged or oil control rings are blocked/fail that bore loses a lot of lubrications and wears down considerably faster. If an injector gets stuck open or overfuels it's game over as well. IMO high quality synthetic is a must in this car from day 1 after seeing enough internals on these cars.

My own oil tests and the dealers leak down tests indicated that I was leaking compression via piston ring in cyl #3. My extreme imbalance in PCV would follow this line of thinking as well.

[aaronc7]

Just verifying here-

you guys are calling passenger side cylinder 1 and driver side cylinder 4 right?