Quote:
Originally Posted by McSpooney
Ahhh that's not what I wanted to read. I was kinda worried it might be a stuck valve.... but I the only test I saw online for a stuck valve was kinda simple and the car easily passed. Just holding a piece of paper up to the exhaust pipe.
Vacuum test seems like the key now! This same one that blue62 described? Teeing off a vacuum gauge into the intake plenum?
This is all happening at idle. Off of idle i don't think it misfires at all. Engine pulls strong too. The head was replaced because it cracked and started dumping coolant into the SAI port on the exhaust.
I swapped the valves from my old head onto the new one. Lapped them, did a leakdown test a few times since and it all seems alright. Rough inspection of the valve guides, valves, cams... nothing showed excessive wear... I really hope i didn't f that up.
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Swapping valves from one engine to another is not a good practice.
Just as swapping valves from one position to another in the same engine is not a good practice.
Your RAKT's show that one bank is running lean and the other is running rich.
So I would check very carefully for an exhaust leak before the O2 sensor and also at the O2 sensor bung weld. A pinhole exhaust leak can cause your issue.
when you do the vacuum test make sure the engine is fully warmed up.
An easy place to TEE in is where the vacuum line from the fuel pressure regulator is connected to the intake. Near the throttle body.
Put one leg of the TEE directly into the intake, one leg of the TEE into the vacuum gauge, one leg into the line to the fuel pressure regulator.
Just let the engine idle. DO NOT rev the engine. Let it idle for 2-3 minutes while you watch the gauge. record the readings. BUT the MOST IMPORTANT thing is what the needle does.
Record any action from the needle. Does it tick??? does it vibrate does it move in any way no matter how slight over a 2-3 minute period with the engine at idle???