So I recently got a valve adjustment and had a compression test before. The readings were 240, 210, 215, 240. Now I want to compression test again in hopes the low compression was due to the valves not closing all the way before the valve adjustment. Now I'm debating between whether or not I want to take it somewhere and spend the money for another compression test, or buy the gauge and battery charger to do it myself. I do enjoy working on my car and always want to learn how to do things myself, but I can't think of other uses for a car battery charger and gauge after I do the compression tests, except for more compression tests.

 

auto zone will rent you all the tools to diy.

 

Didn't think of that, but looked it up and I don't think they rent battery chargers

 

You don't need a battery charger for a compression test

 

I was worried by the time I get to the last cylinder, my battery would be weak and not crank as fast, making it seem like I have low compression.

 

Geez, how many times do you crank per cylinder. It's not a V10. You should be able to run through an entire test and not drain the battery. You can spend under $50 and have an ok tester for at home use. That's cheaper than an hour of labor at a shop if you know what you are doing.

 

I decided to buy a gauge myself. Also you don't need to have a battery charger, but they are nice things to have

 

Do a wet compression test to distinguish what is exactly giving you the low compression in those two cylinders.

To do this: drop a spoonful of oil into the spark plug chamber of suspected cylinder, then perform compression test as normal.

If the compression goes up significantly, than it is your piston rings.

 

I was going to do the wet test, but it was late and I put it back together. I'm just going to get it tested and leak down with some quality gauges.