How to check vehicle compression [tut]

[ktmrider530]

Hey guys, today i will be showing you how to do a basic compression test on your gasoline vehicle.

You will need a compression tool. Available at any auto parts store.
Now this is a two person job. You will need someone in the vehicle at all times holding down the gas pedal. Never let off the gas pedal, ever

Step 1. Pull all the spark plugs, Make sure you number your wires, if you get them mixed up, your firing order will be all screwed up and your car won't run.

Step 2.Now once your plugs are all pulled, screw the checker into place. And have the helper inside the car turn the car over about five times. Then stop. Make sure his foot does not leave the gas pedal. Now, depending on what your vehicle is and what your bore and stroke are, this will vary. Look up what your pressure should be.

Step 3.Repeat this process on all your plug holes, like i said. Make sure the helper never takes his foot off the gas pedal.

Once done with all cylinders, place your spark plugs back in. Make sure you put your wires back on the correct plug.


Now, you may be asking. "why the hell would i need to know my compression?" And the answer is, most of you don't. This is pretty much for people who have an idea of how an engine works.

But for those of you who still want to know. If you have low power, this is the first thing i would check. It can be an indication of a cracked cylinder, blown head gasket, and many other problems.

For those of you who understood this, i hope you enjoy. I made this really quick so i'm sure i missed something but i dunno.

Enjoy. Feel free to ask questions. And PM for a custom tutorial.

[B@nNeD]

Hi my Bro good old uncle B@nNeD will agree with you on this thread 100% now this is A nice contribution to this section, & for everyone else the person inside cranking the engine over & holding the throttle fully open will ensure that the same swept volume of air will be taken in on every cylinder giving you a more accurate compression reading. Nice job on this tutorial my Bro well done keep it up.

(I have rated this thread accordingly once again nice work my freind)

B@nNeD

[ktmrider530]

Thank you B@nNeD.

[majordave]

Actually if you're buying a used vehicle, having the compression checked first is a really good idea. If the compression's bad, it could indicate engine problems, which might be why the owner is selling the vehicle!