| I just got done installing my engine and am having idle issues. Same issues I have always had since installing Z1 tb's but this time I am determined to get to the bottom of it. So I have this theory that the poorly sealing tb shaft plates(I am not talking about the shaft seals) allow enough air to pass to render the idle control devices useless. I have the idle screw turned all of the way in to get the idle down to 900ish and my aac value in nissan datascan always is around 12% which to me indicates a vacuum leak. Well, I have done plenty of boost leak test and believe the only vacuum leak is the tb butterfly valves themselves. So I decided to use my dual intake boost leak tester to block off the tb's completely. I also blocked off the pipes leading to the tb's to force all air to come through the maf's. Just as I suspected it barely idled and for the first time since installing z1 tb's I had to actually back out the idle screw quite a bit to raise the idle to 750 rpms. So now I am confident that the tb's are passing enough air to render the idle control devices useless but I still want to verify that my aac, ficd and air regulator are working. Well my engines to hot to know for sure if the air regulator ever opens up but I can verify that it is closed like it should be. I pinched the hose shut between the balance tube and air regulator and noticed no change in idle indicating the air regulator bimetal shutter has closed like it should be. Next I turn on the AC to trigger the ficd and the idle raises around 200 rpms indicating it is working. Previously with the tb's in the intake circuit turning on the AC did not cause the idle to raise much if at all which to me confirms that if enough air passes through the tb's the small amount of air bypassed by the ficd will have no significant effect on idle. Lastly I used nissan datascan to manipulate the duty cycle of the aac. Unfortunately I believe mine is non-functional as no matter what percent I set it to it had no effect on idle. So I'd like to hear your oppinion and if you agree on both points. 1. I have a bad AAC. 2. The poorly sealing tb butterfly valves pass enough air to render the idle control devices useless. Here is a quick video I made showing the aac issue: link |
