Buy This! Not This! - Comparing Two Compression Testers 

Good video. A bad compression tester gauge will give you a heart attack which is even more expensive than a new engine.

Got the harbor freight tester for my N54 and all 6 cylinders rested 130 which I knew was way too low. This video makes me feel much better

Bro... I just used that harbor freight one and my motor was soo low! I built this thing a few months ago and my heart sank! Like what did I do wrong! It's running good too! Was about to tear into the whole motor. Then I thought... harbor freight... maybe not the best. This video confirms it! Thank you man! Ima buy a new, better tester and try again. Hopefully near that 210!

That is one clean engine bay!

Man, I almost torn into my engine, because of that darn harbor freight compression tester. Thanks.

Thanks for the video, I have a tester on order but had mixed reviews. Checking this video convinced me to get a 3612.

Glad I reviewed this video I just purchased one. I was told if I opened it and there was a problem not to bring it back. Now I can see why thanks for the post.

This was very helpful and will save me some money. Thank you for the video and review.

Great review and advice; i bought the Innova tester; works great; thanks for saving me time and money; !!!!

I have an Innova InnoCompress OHC Plus (EQUUS 3615) and wondered about this product. I'm now more confident this tool, without a blow-mold case, is superior over Harbor Freight inventory. Thank you for your upload.

Thanks dude. Big help!

Thank you for making this video.

Great review! Thanks!

Thanks for the review.

I'm in the middle of the EXACT same thing. Bought it probably around same time as you, but has been in toolbox unused. Cyl1: 150, cyl2 150, cyl3 130, cyl4 90.....uh oh. Cyl1 again.....30! Now it will ready between 2 and 30...... Good video!

Thanks, just checked my 3-decade old tester - it has that schrader valve :-)

My harbor freight guage read 120 on my LQ9 LS. Just about 60 to 70 psi short of specs. Bought the Innova and bam, 190 psi on all cylinder

No matter what you’re testing. I don’t care if it’s a car or truck engine. A chainsaw, a motorcycle, a lawnmower, WHATEVER. A compression tester absolutely has to have a schrader valve right there in the threads that screw into the spark plug hole. The schrader valve cannot be anywhere else down the line. It has to be right there in the spark plug hole. The length of the hose doesn’t matter. Why they would even produce a tool that’s completely useless makes no sense. Lol

Thanx for the review. They just opened a Harbor Freight here. It's booming. How do you really know how accurate a compression tester is if you don't have something to test it with?

I love listening to um videos.

Dude! That is a nice lookin engine bay! 👍🏼

Had the same problem only shows 25psi on GOOD engines. The reason is like you said it reads the air pressure in the HOSE as well which is WRONG

@ 5:35 , did you say "granite" ? Nice review. Thank you.

Did you manage to correct the compression on cylinder 1, did it just need valve clearances done?

I had the same results very low compression with the Harbor Freight gauge. It was showing 90 psi on a good running engine. Most engines you need to have at least 100 psi to run at all so I knew it was the gauge.

I've rented a compression tester from orileys 3 separate times and tested it on 3 motors and it never went over 60psi, im hoping it's just the tester as I just spent $350 on a boat motor only for it to say it has 60psi on both cylinders

The adapter on my China junk got stuck on the first cylinder lol it definitely read low so I'll need to get a quality unit.

I agree. My harbor freight compression tester is junk.

bought an harbor freight tester and i got 90psi on all 4 cyl of my motorcycle that should be 180psi....the problem with this tester is they are charging 20% restocking fee if you are returning it...im guessing there are lots of returns for this tester.....LOL

The carry case is to bring it to the trash can.... I bought one of them too...

Use the connection and carry case and use the other guage

S2000? Looks that way 👍

Harbor Freight one had me sell and outboard for cheaper due to low readings. :-(. I just threw it in trash.

could u pls do video for how to crank a car with start push button for compression test. I know how to crank with key. but always want to know how to crank with start push button.

Ummm thank you for this video

Any advice on how to pick and AC gauge tool?

JAS EUGENE You completely missed my point and obviously don't know what you are talking about. More volume does not decrease air pressure IF YOU ARE SETTING IT FOR A CERTAIN PSI. You may need to add more air to get to that specific psi, but in the end you're still going to be able to get the same psi with more or less air. It will take more air to reach the same amount of pressure but in the end the pressure will be the same. Like I said earlier and used as an example. Most bicycle tires are rated for 40psi! And most pickups also are aired up to 40psi. According to your theory then if you were to take a tire pressure gauge and use it on a bicycle and it read 40 psi then because of the tire size you are basically saying that a truck tire wouldn't read 40psi because of size even if it was in fact aired up to 40 psi. However, we all know this to be incorrect. You can use a tire gauge for all sorts of moving vehicle with tires and they will all read 40 psi if they were all aired up to that exact pressure. Tire size will not matter. Yes one may hold more air then the one next to it but it they were aired up to 40 then they will all read 40. You dont need a different type of gauge for every type of tire. So once again having extra volume (air) inside of a compression tester doesn't matter. It's still whatever psi you pumped through the gauge and the psi is all that matters. Yes psi stands for pounds per square inch. but it's not referring to pounds as in volume pounds. its talking about pressure basically per square inch. Simply mathematics as you say would tell you this but apparently you don't understand what the hell you're talking about.

I made the same mistake🤦‍♂️

Im not certain that your theory holds any validity. I understand what youre saying. However when youre measuring compression, youre not measuring volume. Youre simply measuring pressure. Think of it like measuring psi of a tire. Bike tires measure just as high in psi as a car tire even though they obviously hold less air. So even though yes the hose may have extra air in it, remember pressure is important. Not volume. So once youre guage hits a certain pressure, then whether the valve is in the end of the tube or at the tip of the guage, the psi will still read say 45psi, because thats the amount of force on the gauge.

Im buying it to see if my s2k motor is healthy 😀

Isn't the compression tester only to see difference in pressure not the value itself?

Now test the madox fuel pressure tester

how do we know you used it correctly

The Maddox master kit is way better then both of those

Please use fewer "ums"

"Thanks China" ☹️

Just rebuilt my kx250 because of that hf piece of shit

It’s not the a actial pressure reading you are looking for in a compression test. It the pressure difference. Between the 2 testers the pressure difference of the cylinders is the same

Uh.uh.uh.uh