Compression test?

[Speed JUnkyz]

Can someone help me with checking my compression on the Evo?

Sounds simple, I just need the tools and resources.....Anyone want to help me? :D :D :D :D

[Scrapy]

I would if I were up there. Its really easy, I can post up how to do it if you do not know, let me know.

[Speed JUnkyz]

Well yeah do that, but also let me know where to get the shit I need for it

[Scrapy]

Damn, the website I used to learn how to do it is down so here is a rundown.

1.) go to autozone and buy or rent a compression tester ($25.00 to buy, worth it just to buy it so you have it for future use)
1.5) Drive the car hard going home to give the battery the strongest charge possible. A weakish battery will net lower compression test # results.
2.) Find out where the fuse is for the fuel injection (I dont know where it is on the EVO) Pull it out.
3.) Remove Spark Plug #1
4.) Insert compression tester into hole of Plug #1 tighten down by hang snugly
5.) Get Liz to turn the key and crank the car for 10 seconds. You will see the needle jump up on the tester guage . After she is done cranking the car for 10 seconds, write down the number that the needle reads on the guage.
6.) remove compression tester
7.) Reinstall Spark plug number 1
8.) Repeat for 2,3 & 4
9.) Dont forget to reinstall the Fuel injection Fuse!!!!!!
10.) post up the numbers for us to see. They should all be semi close to each other. if one or more is considerably lower than the rest, you have a problem.

[Speed JUnkyz]

Ok Im lazy and also would like the info for the site......

Can anyone find me the Fuse for the fuel Injection on a 2003 Evo 8?

I got 10000 credits in for it..... :D

[Scrapy]

I did find out that fuse in my car that needs to be pulled is the MPI Fuse. Hope that helps

[Speed JUnkyz]

Well if it did I will be sure to credit you....Should know tonite or tomorrow

[Scrapy]

One more thing, and i forgot to add. Make sure the gas pedal is 100% floored when doing comp test!

[Scrapy]

I can't post where I got it because its on Evom.net and I know you don't like that site HAHAHA

[ShadeTree]

Rather than pulling the fuse for the fuel injection, you can just unplug all the fuel injectors. The idea is to not flood the cylinders with gasoline, and prevent the motor from running.

you an also just use a jumper wire to the signal wire on the starter. if the key is in the off position, but you put power to the signal wire on the starter, the engine will crank, but the injectors will not fire, and there will be no pressure from the fuel pump. same effect.

You can open the throttle 100% or not, it does make a small difference, just perform the compression test the same way for each cylinder. also, either remove all the plugs, or do them one at a time. Lastly, a hot engine will produce higher compression test numbers than a cold engine, but as stated by Scrapy, all you are looking for is the numbers being close together. i see anywhere from 120 to 170, and i'm in denver at 5,000 feet.

last tech tip. As a general rule of thumb .... if you have a cylinder with low compression, shoot a tablespoon of oil into the cylinder and retest. if the low compression is due to poorly seated rings, the oil will increase the compression. If the compression is being lost through a bent valve, the compression will remain the same. a cylinder leakage test would then tell you where the compression is being lost, intake valve, exhaust valve, or rings.

[Boo-Rad]

Rather than pulling the fuse for the fuel injection, you can just unplug all the fuel injectors. The idea is to not flood the cylinders with gasoline, and prevent the motor from running.

you an also just use a jumper wire to the signal wire on the starter. if the key is in the off position, but you put power to the signal wire on the starter, the engine will crank, but the injectors will not fire, and there will be no pressure from the fuel pump. same effect.

You can open the throttle 100% or not, it does make a small difference, just perform the compression test the same way for each cylinder. also, either remove all the plugs, or do them one at a time. Lastly, a hot engine will produce higher compression test numbers than a cold engine, but as stated by Scrapy, all you are looking for is the numbers being close together. i see anywhere from 120 to 170, and i'm in denver at 5,000 feet.

last tech tip. As a general rule of thumb .... if you have a cylinder with low compression, shoot a tablespoon of oil into the cylinder and retest. if the low compression is due to poorly seated rings, the oil will increase the compression. If the compression is being lost through a bent valve, the compression will remain the same. a cylinder leakage test would then tell you where the compression is being lost, intake valve, exhaust valve, or rings.

http://i299.photobucket.com/albums/mm283/djsyda/holy_thread_resurrection_batman.jpg

[EvoJoe]

Might be a thread resurrection but VERY useful info! Thanks man!

[ShadeTree]

thanks gangstar, i don't even look at the age of a thread, i just add something if i think it may be useful. around the shade tree were just looking to help in any way we can.

thanks again

[EvoJoe]

thanks gangstar, i don't even look at the age of a thread, i just add something if i think it may be useful. around the shade tree were just looking to help in any way we can.

thanks again

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