How to Perform a Cylinder Compression Test

[Greendewful]

you dont need to do all of that

[zerojett]

Very informative. Good job guys.

You should make the audio equal in each clip though when you edit it. Excellent info though.

[cobrachoppergirl]

Why don't all engines just have an electical compression test analyzer system built onto them so that at any time all you have to do is look at the dash to see this nonsense instead of disconnecting half the engine. Not only that, but monitor water temperature, oil pressure, and battery voltage at all times and turn a red color when they are out of range.

[ttcautotech]

@cobrachoppergirl

My guess would be because of the added expense. Not everybody would pay to have that feature. Some cars will do a cylinder balance test, but only if you have access to a scantool. It's possible to run a relative compression test with an Oscilloscope by measuring the starter current draw as the engine is cranked. Each time the cylinder comes up on compression, the current rises. We look to see if they all rise equally. Not perfect, but a quick indicator cylinder condition.

[5ky5tr1d3r]

@ttcautotech Yes,it would increase costs a bit,and most older cars was made in time when compression testers were rare and hi-tech :) But today I think that almost every car with a good on-board computer can perform diagnostics on his own

[genericaction]

@cobrachoppergirl My car is older than I am, so...

plus it would take away all the fun!

[LookieLoudLou]

Thanks for this video guys, good job.

[0jayelbee]

Nice video except you do not need to disable fuel and ignition systems if you are using the remote starter switch as they are not enabled with the vehicle ignition key off.

[ttcautotech]

@0jayelbee  we show how to disable the fuel and spark because alot of people will use the starter to turn the engine. Also, we've noticed on some vehicles power would travel back up the crank circuit and enable the spark and fuel during cranking when we used a remote starter switch.

[jwallis123]

thanks yall. greets from texas

[valflyinf]

Thank you very much now I need a gauge.. hehe.

[fleckx]

Daaamn, it's a nice informational vid but you should have leveled out the audio in each clip!

[luftpirate]

Great video, glad to see students taking passion in learning.

[lagunaskater]

WHATS THE FIRST SONG!?!?

[samburger077]

@lagunaskater crawling in the dark, hoobastank

[DevaJones03]

Nice vid, where was this shot? Gotta love those southern drawls lol

[subaman123]

Great job, very informational.

[bigblocksrock]

is this a gm 3.8

[JorgeAlejandro1970]

very good guys, thanks, very helpfull

[BethShanFan]

Would you need to hook up a spark tester to each coil wire or is one enough for them all?

[ttcautotech]

If the engine has multuiple coils it is best to unplug their electrical connectors as in the video. If you have just one coil, there should only be one coil wire and that is the one to insert the spark tester. If you have a Honda, Toyota, GM or other make that has a single coil installed inside the distributor or cap, then its best to unplug the elctrical connections to the distributor.

[Gill1689]

Couldn't you record it without those people talking in the background? The sound quality's terrible.

[ttcautotech]

The video was recorded as a small, group project and done during class with other students working in the shop.Unfortunately, quiet on the "set" was impossible.

[ttcautotech]

The video was recorded as a small, group project and done during class with other students working in the shop.Unfortunately, quiet on the "set" was impossible.

[MrMikedarrow]

could you just turn the fly wheel with a wrench?

[ttcautotech]

No, you couldn't turn the engine fast enough to get a true compresion reading.

[bullmoose33]

What do you put in the combustion chamber for the wet test? I couldnt hear the guy.

[ttcautotech]

motor oil. About a teaspoon full. Do not put it in a diesel engine. There may not be room for it and damage may result.

[2cv56]

Very good idea to make this kind of videos +++

[meaningintragedy01]

Those coil wires look horrible

[ttcautotech]

Yes, 16 years and thouands of students will do that.

[Sirrom0206]

I like your video, but your process is invalid on a Honda or Mitsubishi engine.

Unfortunately, each plughole is recessed in the head in a 6 inch deep steel cylinder.

I need you to show me how to test one of theses engines.

I I

I I

I II I

I II III How do I get my tool down here in the cylinder then get it out?

[ttcautotech]

Recessed sparkplugs have been around for decades.  In fact, Its begining to look like the majority of new cars have or will have recessed spark plug holes. We still use the same adapter to reach down in the hole. The rubber hose is stiff enough that it wants to stay straight and will thread in fine. If we ever do run into one that creates a problem an adpater that is made of straight steel tubing can be purchased.

[Sirrom0206]

I had a bad kit. Like you said the rubber hose on the second kit came out as required. I'm a power plant diesel engine mechanic, not a mogas mechanic. Our engines are as big as 2-story houses and support +40K people (Million Watt systems) thus we don't use little rubber tools to troubleshoot. I know the process is the same, but we use a crane to pull pistons and move heads.

I normally take my cars to the shop because I don't have time at the house.

Thanks for your reply & support!

[mbramel]

thank you very much. really appreciate it

[2scratchthis]

awsome job guys your video will help me out alot on my 350 5.7liter tbi engine, thank you so much ya!!!!!!!!!!!

[negativeeffect15]

only the best

[JUYANIK]

Thanks guys, much appreciated!

[chev3502]

Nice work guys now I can do this on my 350chevy and do it the wright way cheers form AUSTRALIA.

[rosureju]

Thanks guys! You rock!!!

[angela07221966]

Great Job !!!!!!!!