Cold Compression Test Questions - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Likethunda · 05-21-2012, 12:14 AM

Hello, Im currently replacing a bad fuel injector on my 300zx TT

I wanted to do a compression test, but (i cannot start the car) obviously because i removed the Plenum.

Should i just wait until i put everything back together for a warm compression test.

or can i still get some Good DATA from a cold compression test?

ROGUE_RB · 05-21-2012, 05:47 PM

Its better to test cold..just pull the fuel pump fuse and test, it won't start just like being on a crate at the japer's

Highway Riding · 05-21-2012, 05:50 PM

Some say a leak down is more important. Do both if ya can. Leakdown & compression

Likethunda · 05-21-2012, 08:06 PM

Quote:

Originally Posted by ROGUE_RB

Its better to test cold..just pull the fuel pump fuse and test, it won't start just like being on a crate at the japer's

I asked because everyone tells me that to get an accurate compression test it needs to be warmed up first.. but you say cold is also fine... Hmmm yay or nay

ROGUE_RB · 05-21-2012, 08:21 PM

If u test it cold it's going to recreate initial first starting.. If it runs like crap then it's not gonna run much better hot..test it cold if ur numbers aren't quite what u want them to be, put a small shot of oil in each cylinder and retest.. if it improves u need rings

jr_ss · 05-22-2012, 05:06 AM

Your numbers will be more accurate if you were to do it warm/ at running temp. However, you can get an idea what your comp is with it cold. Leakdown tests give you a better overall picture of the health of your engine.

05-21-2012, 12:14 AM	#1
Likethunda Zilvia Junkie Join Date: Feb 2010 Location: Southern CALI Age: 31 Posts: 423 Trader Rating: (4) Feedback Score: 4 reviews	Cold Compression Test Questions Hello, Im currently replacing a bad fuel injector on my 300zx TT I wanted to do a compression test, but (i cannot start the car) obviously because i removed the Plenum. Should i just wait until i put everything back together for a warm compression test. or can i still get some Good DATA from a cold compression test? __________________

05-21-2012, 05:50 PM	#3
Highway Riding Zilvia Addict Join Date: Feb 2010 Location: Out on the Highway! Posts: 602 Trader Rating: (1) Feedback Score: 1 reviews	Some say a leak down is more important. Do both if ya can. Leakdown & compression __________________ The Sun Rises in the East!

05-22-2012, 05:06 AM	#6
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	Your numbers will be more accurate if you were to do it warm/ at running temp. However, you can get an idea what your comp is with it cold. Leakdown tests give you a better overall picture of the health of your engine. __________________ My SR20VET

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05-21-2012, 05:47 PM	#2
ROGUE_RB Leaky Injector Join Date: Oct 2011 Location: waterloo Age: 32 Posts: 65 Trader Rating: (0) Feedback Score: 0 reviews	Its better to test cold..just pull the fuel pump fuse and test, it won't start just like being on a crate at the japer's

05-21-2012, 08:21 PM	#5
ROGUE_RB Leaky Injector Join Date: Oct 2011 Location: waterloo Age: 32 Posts: 65 Trader Rating: (0) Feedback Score: 0 reviews	If u test it cold it's going to recreate initial first starting.. If it runs like crap then it's not gonna run much better hot..test it cold if ur numbers aren't quite what u want them to be, put a small shot of oil in each cylinder and retest.. if it improves u need rings