compression test question

[awdwhip]

how do you do a compression check? is it easy?

 

[TargeT]

its very easy, the simplest ( & definatly not 100% correct way ) is to pull all your plugs (disconnect the plug wires , lay the plugs out somewhere etc) screw in the compression tester (like 25 bucks from napa) put the throttle to the floor and crank for a full 5 seconds. record the readings for each cylender (make sure you clear the tester after each test with the little button on the side)


too easy eh?

your numbers should be with in 10-15 of each other and be 150+ unless you have extra low compression pistons or something.

 

[oldman]

http://www.dsmgrrrl.com/FAQs/compression.htm

 

[TargeT]

http://www.dsmgrrrl.com/FAQs/compression.htm

there's the right way

Oldman strikes again!

 

[oldman]

Oldman strikes again!

Yes old people have a lot of time on their hands. I just hope that i have better luck than you on my gt12 install this weekend, I had to dent the water pipe pretty bad so I hope nothing will be leaking.

 

[TargeT]

Yes old people have a lot of time on their hands. I just hope that i have better luck than you on my gt12 install this weekend, I had to dent the water pipe pretty bad so I hope nothing will be leaking.

i fixed my leaking water pipe with some plumbers tape & grey RTV,.. I think i just got a "bad turbo" or possibly it was hurt in the accident. i'm sure you'll be fine. & you'll LOVE the turbo! ball bearings are awsome. when your in the 3,800rpm and up range full boost is nearly instant (though on that note, becareful cuz if your boosting too high it will ROCKET up there, so turn that boost controller low and work your way up )

 

[oldman]

(though on that note, becareful cuz if your boosting too high it will ROCKET up there, so turn that boost controller low and work your way up )

Thank you captain obvious.

 

[TargeT]

Thank you captain obvious.

just relyaing my experiences. i wasn't aware that i had a 21lb spring in my tail & it scared the crap outta me when i first went out and jumped to 27lbs.

i really wasn't ready for how fast the spool up was on the turbo, i read 15%, but it seemed a LOT faster than that to me.

 

[redgst95]

theysay you are supposed to pull the mpi fuse out where would that be located on a 2g?!?! i couldnt find it in my fuse box???

 

[TargeT]

theysay you are supposed to pull the mpi fuse out where would that be located on a 2g?!?! i couldnt find it in my fuse box???

truthfuly, i wouldnt worry about it too much. its just some extra fuel. (sure its not the correct way. but it works )

 

[CyberEye]

I never understood the purpose of holding the gas to the floor.

 

[TargeT]

I never understood the purpose of holding the gas to the floor.

gotta have that throttle plate open to get the air into the cylinders to compress it

 

[oldman]

I never understood the purpose of holding the gas to the floor.

My guess is to allow free flow to the head without creating vcuum between tb and head. Not 100% sure though.

 

[tstkl]

i just dropped my ecu off at newlogics to get the capacitors replaced (off topic), and while i was there i talked to a guy who said he saw paul do a compression test on my car(on topic,...)... i knew that paul had done a compression tests, and the results were "good" but that guy said that i had 150 across the board, and that that is perfect... now this site is saying 164 is perfect for a stock engine (what i have)... which is it? im guessing that 164 is perfect for a stock engine, cuz my car has 91k on it, and that guy probably just ment 150+ on all cylinders, or maybe somehow they all had 150... either way im guessing my engine isnt perfect, but as far as 15 year old engines go, im sure i shouldnt be complaining..(and im really not, just asking a question)

 

[tylerk]

theysay you are supposed to pull the mpi fuse out where would that be located on a 2g?!?! i couldnt find it in my fuse box???

On a 2g it's the fuse labeled "ENGINE"

 

[TargeT]

that guy said that i had 150 across the board, and that that is perfect...

the service limit on our engines is like 133psi on a compression test, 150 is perfectly fine

look for anything in the 140-180 range ( as long as each cylinder is with in 10 psi or so of eachother) and your engine is fine. anything below 140 and your prolly gonna want a rebuild.

 

[ltho98]

Kinda depends on your altitude too- i'm 5200ft high with average DA's around 7500-8000 on a n average july. I got 140psi, service limit is 133. But really, what matters most is consistency as compression checker devices can vary. (IMO)

Instead of pulling the MPI fuse, i just disconnect my CAS. but thats just me.