CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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Hi guys, what is the criteria for the pulse width modulated EGR solenoid to be active? I'm trying to find an easy way to verify I am going closed loop. I am having a problem getting the dwell on my MCS to range properly so I need to make sure I am indeed in closed loop. I can hear the EGR solenoid clicking loudly after a few minutes of run time. Does this mean I am in closed loop, or can the EGR solenoid also operate in open loop?
__________________ 1989 Trans Am, 1979 Z28 w/ Holley Stealth ram and MAF '165 ECM, 1988 Chevy K1500 w/ L98 and TPI swap, 2003 Mercury Marauder, 2004 Taurus SEL
My testing has also shown only closed loop. Which makes sense; older, non-CC cars used a thermostatic valve to prevent vacuum from reaching the EGR valve until operating temperature was reached.
Ok this is good news, this means I am going closed loop since the EGR solenoid is functioning. This thing is loud! Is it normal for the EGR solenoid to make a very audible clicking sound? It is a lot louder than the clicking of the MCS.
I would say it is not normal. Especially at idle when the solenoid is fully open (venting all vacuum to atmosphere so the EGR valve doesn't open) which is "0% EGR opening" and NO pulsing of the solenoid should be taking place. i.e. it should be silent at idle.
but is "venting all vacuum to the atmosphere" still going to involve duty cycling the solenoid? I'll have to find what the heck I did with the FSM and get my vacuum gauge and check what the solenoid's output looks like.
You raise a good point. I think zero means just that- ZERO, no cycling of the solenoid at all, but don't quote me on that. I can't ever recall "hearing" the EGR solenoid cycling.
