How smooth should an LT-4 idle?
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Instructor
Joined: Mar 2012
Posts: 201
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From: Kennewick WA
How smooth should an LT-4 idle?
I can feel a slight shake to the engine. It ain't much but my four banger Subaru idles perfect by comparison. If it's supposed to idle perfect, what should I look for as my problem?
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Joined: Jul 2011
Posts: 84
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From: Palm City FL
I have a 96 CE and the idle is without any shake and is very smooth by my experience. I had a 67 with a 327 with fuel injection and I feel the LT4 idles better. I would refer to the FSM to isolate the root cause.
Good Luck
Good Luck
Race Director
Joined: Dec 2006
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IMO the firing order of gen 1+2 SBC means that it will never idle like a Japanese inline 4. The LSx firing order smooths it out some.
If you think it's not as smooth as it should be the problems are almost always vacuum leaks. Block off the vacuum ports and make sure the PCV rattles and do a test. If idle improves substantially then reconnect the vacuum supplies one at a time to find the culprit and run it.
If you think it's not as smooth as it should be the problems are almost always vacuum leaks. Block off the vacuum ports and make sure the PCV rattles and do a test. If idle improves substantially then reconnect the vacuum supplies one at a time to find the culprit and run it.
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From: Park City Utah
To the OP; As 94z said, check for vacuum leaks, worn plugs, cap/rotor, wires, the injectors may need replacing... There is a bit of a laundry list for you.
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