2015 Kia Rio EX 122000 miles
I've seen your video on testing the cylinders with a multimeter hundreds of times and I finally have the tools I need to do it myself, but when I checked my fuse box I could not find the EFI fuse. I tried searching online and they say the ECU should do the same thing but my car has like 5 ECU fuses and I don't want to do damage to my car.
How can I test the cylinders on my vehicle with the multimeter without causing engine damage?
There is nothing wrong with my cr but I want to get some practice before I go and I buy another used car.
Do a dry/wet compression test. You don't use a multi meter for that.
If you're doing a compression test as @doc says, you don't want your car to run. You also don't need a multimeter. You need a pressure gauge that screws into the spark plug hole.
You can temporarily disable your fuel system by pulling out the fuel pump relay and running the car until it stalls. Crank it over a few more times to make sure it's fully depressurized. The fuel system will not repressurize until you put the relay back in. Do your wet and dry compression tests at this point.
When you put the relay back in, turn the key to run and back off for a few seconds. Do this 4-5x to repressurize the fuel system, then try to start it.
You're talking about doing a relative compression test by monitoring how much current the starter draws on the compression stroke of each cylinder. That's OK as far as it goes, you can find a dead or damaged cylinder that has little or no compression that way, but it does not tell you anything about the overall health of the engine the way a wet/dry compression test will. (If you have low compression on all cylinders the relative compression test will not pick that up.)
without causing engine damage?
It's got nothing to do with engine damage. If you don't disable the engine, it will start running! This test doesn't work on a running engine , right?
There is nothing wrong with my cr but I want to get some practice before I go and I buy another used car.
Don't use this test on used cars. If a cylinder is dead you will feel it. Don't buy cars with engines that lope or shake. It's more of a quick troubleshooting procedure to locate a bad cylinder.
If you are trying to ascertain the health of an engine, then you should use a gauge and do a proper compression test like in the beginning of the video.
I could not find the EFI fuse.
Did you look up what EFI means? Electronic Fuel Injection.
Owners manual page 7-54 (fuses), or diagram on bottom of fuse box lid:
You have one labelled INJECTOR. Same thing.