Subject	Does the a/f schedule directly depend on VTC advance?
Posted by	Zarcasm(Hfd, CT) on April 21, 2010 at 7:02 PM
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In Reply To	I have a hard time visualizing the VTC mechanism being posted by Ash's Z on April 21, 2010 at 07:36 AM
Message	If the VTC cams didn't stop at the appropriate stops, or didn't switch quickly at the transition, the ECU would have no way of knowing it and would try to "learn out" the effect with help from the O2 sensor with a non-optimal a/f across the entire power range, right? This difference would be especially pronounced if there were separate schedules for VTC ON and VTC OFF. If so, you might not notice any impact in one of the two modes of operation. Does the a/f schedule depend on which VTC mode the engine is operating in? How can I prove my VTC system is operating at spec? The hear-if-it-clicks test is too coarse to prove anything in my case. Thanks again for your comprehensive response, Ash. Zarcasm(Hfd, CT) view My Technical posts (click here) view My General posts (click here)
Follow Ups	What controls the amount of VTC timing advance? - Zarcasm(Hfd, CT) 18:13:19 04/20/10 IIRC VTC solonoids are duty cycled - Spddracer 19:44:17 04/20/10 I believe its just off of oil pressure. - Machtavian 20:00:06 04/20/10 I think you'll find it engages above idle... - zx299 20:12:50 04/20/10 Thats what I said. (n/m) - Machtavian 20:51:31 04/20/10 Where did you come up with the 2,500 rpm number? - Zarcasm(Hfd, CT) 21:20:16 04/20/10 That's where Greg D. sets them to come on if my memory - Machtavian 21:29:43 04/20/10 nope, try again (n/m) - Seb@Specialty-Z 23:32:10 04/20/10 My understanding of the VTC system..... - zx299 19:54:48 04/20/10 They are either on or off depending on engine load. - Ash's Z 19:55:30 04/20/10 Interesting , I must be thinking too new ;) - Spddracer 20:14:36 04/20/10 This was supposed to be... - xpwarrior 20:52:16 04/20/10 Thanks Ash. Ever heard of a VTC acting lazy and sluggish? - Zarcasm(Hfd, CT) 21:12:02 04/20/10 I have a hard time visualizing the VTC mechanism being - Ash's Z 07:36:11 04/21/10 Does the a/f schedule directly depend on VTC advance? - Zarcasm(Hfd, CT) 19:02:23 04/21/10 It's a simple on/off mechanism with the control variables - LitlElvis 07:04:52 04/21/10 is this the reason for the caps on the back of them melting? - LJZTT 15:14:08 04/21/10 No relationship whatsoever - LitlElvis 16:22:24 04/21/10 Thanks LitlElvis - Zarcasm(Hfd, CT) 19:12:56 04/21/10 My guess is the closed loop a/f adjustments do not base - LitlElvis 23:08:42 04/21/10 I recently used ATF to clean out the oil - Zarcasm(Hfd, CT) 20:10:20 04/22/10
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