what is a leak down test

[lazyeye]

Ok, I am a complete noob that is stated in the above question but I sill would like know what a leak down test is, what it measures, where can i have it done, and what are good and bad readings(numbers) for this test like what should test say to mean its good etc... thx, any imput would be appreciated!

[Ghettokracker71]

Did you search?

[idlafie]

Ghetto,
I give lazyeye the benefit of the doubt...as a nOOOB I don't think he's gonna know much. So we have to slap him in line & give him a quick edumakation!! hahaha...just kidding!! 80)
A leakdown test is practically the same as a compression test...just another wording used. see attached.
http://www.2gnt.com/www/corbin/comp.html
Only difference is...on the KA engine the compression readings are lower...150-175 I think...don't recall off the top of my head.
Anyhow, hope this answers your question lazy.
Diego
'95 SE
PS:
you might want to think about changing your screen name if you're gonna post questions like this!!..hahaha..

[vvtisupra]

where are the relays on a 92 240sx for the fuel and spark ?

[idlafie]

where are the relays on a 92 240sx for the fuel and spark ?

Fuse panel by the driver side kick panel. Pull the fuse that goes to the fuel pump. As for the distributor, pull the spark plug wire that goes from the ignitor/coil to the distributor cap. If you don't see one, then disconnect the wiring harness that connects directly to the distributor. That ought to kill the spark going to the distributor.

Anyhow, hope this answers your question.

ID
'95 SE

[orion::S14]

To clarify a few things:

1) Leakdown and compression tests are quite different - Compression test measures the highest PSI that the cylinder can create in a few revolution, just shows if the engine is seems healthy. Leakdown pressurizes the cylinder with a compressor and then calculates the % of air that escapes over time...and can help you locate where the cylinder is losing the air - Out the valves, rings, whatever...

2) Easy way to keep the injectors from firing is to just unplug them at the top of the injector, then pull the wire off your coil. I typically pull the fuel pump fuse anyway, but it can be done like that...

3) And KA24DE compression readings should be:

179psi = standard spec (decent, healthy motor)

155psi = probably time for a rebuild

Most will read in the 180-190psi range...I have a 85k motor that reads ~185-190 across the board, and a 162k motor that reads +180 in all four.

Remember, motor needs to be warm, and the throttle held wide open for the test to show accurately.

- Brian