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Hi. Can someone help me understand the IAC Valve/air by-pass/ECM relationship?
I am getting an intermittent IAC Valve/by-pass air screw code warning 3-1 on my 2009 DF50. The motor was serviced 4 months ago, and it was okay except it was wont to stall too easily when putting it in gear, so a week or so later I adjusted the by-pass air screw (half a turn, maybe?). The intermittent alarm started soon after (but not immediately after) I made this adjustment. My working assumption is that the two things are related. Basically, sometimes the alarm comes on at low speed/idle, but usually stops if I switch off and re-start the engine. The engine is otherwise running sweet as a nut.
I have read the manual on the self-diag system, but confess I am none the wiser. I adjusted the air by-pass to get a slightly higher idle speed (an increase in air volume, right?), so presumably the phrase "...the ECM controls the IAC valve duty to decrease to maintain the idling/trolling speed specified." applies. Ignoring the woeful English, doesn't this mean that the IAC valve is trying to compensate for my adjustment? This being the case, does it mean that I can't adjust the idle speed like this? And if so, then what's the purpose of the screw adjustment?
I'll probably end up adjusting the screw back a bit, but then I'll end up with the original issue again. Can I resolve it (easily) any other way, or do I need to get the mechanic involved again?
I could strip down, clean and rebuild the Solex Carb on my Dadīs 1964 Hillman Minx blindfold. Balancing the twin SUs on my mate's MG was tricky, but doable. The after-market twin webbers on my Triumph GT6 were a pain, but I understood how they worked. But when they started with EFI and EMCs and E-whatever, I admit I lost the plot....
Any advice and guidance appreciated as always.
I am getting an intermittent IAC Valve/by-pass air screw code warning 3-1 on my 2009 DF50. The motor was serviced 4 months ago, and it was okay except it was wont to stall too easily when putting it in gear, so a week or so later I adjusted the by-pass air screw (half a turn, maybe?). The intermittent alarm started soon after (but not immediately after) I made this adjustment. My working assumption is that the two things are related. Basically, sometimes the alarm comes on at low speed/idle, but usually stops if I switch off and re-start the engine. The engine is otherwise running sweet as a nut.
I have read the manual on the self-diag system, but confess I am none the wiser. I adjusted the air by-pass to get a slightly higher idle speed (an increase in air volume, right?), so presumably the phrase "...the ECM controls the IAC valve duty to decrease to maintain the idling/trolling speed specified." applies. Ignoring the woeful English, doesn't this mean that the IAC valve is trying to compensate for my adjustment? This being the case, does it mean that I can't adjust the idle speed like this? And if so, then what's the purpose of the screw adjustment?
I'll probably end up adjusting the screw back a bit, but then I'll end up with the original issue again. Can I resolve it (easily) any other way, or do I need to get the mechanic involved again?
I could strip down, clean and rebuild the Solex Carb on my Dadīs 1964 Hillman Minx blindfold. Balancing the twin SUs on my mate's MG was tricky, but doable. The after-market twin webbers on my Triumph GT6 were a pain, but I understood how they worked. But when they started with EFI and EMCs and E-whatever, I admit I lost the plot....
Any advice and guidance appreciated as always.