Compression Test?????

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R

ryangt

Senior Member
how do i do a compression check on my d15 rex? im trying to get an idea of how strong the motor is, i have the gauge but how do i get everything set up for readings and what kind of readings should i be looking for when i do the test?

all help is appreciated
thanks
 
Disable injectors (unplug fuel pump fuse or something)
Disable spark (unplug distributor)
Pull all spark plugs
Plug tester into cylinder through spark plug hole
Get in car
Floor gas pedal
Crank engine for 8 compression pumps (or just until gauge stops increasing)
Get reading
Repeat until satisfied

Just make sure all your cylinders read within 10% of each other, 5% or less variation is excellent. You'll probably get readings in the range of 170-200psi. I don't know what the HF engines are supposed to read at.
 
disingage Dissy, fuel, take all plugs out (spark plugs), Prop open throttle, turn motor over for 4 or 5 commpression strokes. that will burn your starter up. just did a couple of comppresn tests today.
 
yeah im gonna go ahead and say three strokes is fine as long as its all going to the guage, and not blowing by. Thats will kill your battery is what it will do lol. Maybe i have just had gayy problems with batterys so much that i like to keep use down. I do know for a fact though 3 isa book number and tryed and true, it really shouldint take more then 3.
 
You usually won't peak on 3 pumps- that's why I use more. I've never had a problem with killing the starter or battery, and I usually run a compression test to 8 pumps twice per cylinder... I like to get more than one reading.
 
i didnt know you have to disable fuel...oops. :lol: i just crank it until it stops increasing.
 
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