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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Trying to troubleshoot a rough idle with slightly low and erratic vacuum.
I expected slightly rough idle with the Lunati 20080130 cam, which is similar to the LT4 Hot Cam.
Here's the link to the video:
I set it up exactly like the ramjet 350. PCV valve
installed under manifold and connected to vacuum line above it. Two breathers in valve covers. It idles rough but revs correctly.
Recently I had the pcv setup similar to the TPI, but the engine never revved correctly and had a poor throttle response. Ramjet 350 PCV
That would likely be at least part of the problem.
The correct setup gets the makeup air from behind the MAF but before the TB, NOT through "breathers". Using those allows air to bypass the MAF. The ECM cannot effectively meter fuel when there is unmetered air (air that it doesn't have any way to know about) entering the intake.
A speed/density type of system can be hooked up the way you have it; but not a MAF.
Connect the PCV like it's supposed to be in your system: TB port in front of the blade to one valve cover, TB or plenum port behind the blade with vacuum on it to the PCV valve. I'm not guaranteeing that this will "cure" your issue, as you may need further tuning; but it'll FOR SURE clear up a glaring mistake that is certain to cause idle problems.
Actually, it is a speed density system. I am using a MAP sensor and EBL flash ecm. What looks like a MAF is actually a black PVC tube just to keep the same intake system.
