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Posted: Thu Jul 27, 2006 12:45 pm
by BlackHat
My only concern with that approach would be that the hole for the AAC is smaller than the one for the Air Regulator. It may not be able to push enough air during startup to run at normal open loop warmup rpms.
What other reason does an engine need a idle air control for besides the regular idle screw and open loop startup? I don't really imagine the coolant cooling down while it's running... at least not to the point it'd need to idle high.
Posted: Fri Jul 28, 2006 8:06 am
by RNash
I did some research for you.
You can find a service manual here
http://www.zeroyon.com/index/content/view/24/47
Look in E_Theory.pfd
The AAC valve appears to be a PWM closed loop used for 'fine tuning' idle speed.
The 'Air Regulator' is a warm-up valve, the wire feeds an electric heater to help heat the valve.
The FIDC valve is a load compensating on/off valve.
You may be able to get by with just the air regulator wired to the fuel pump relay (for warmup), and the FIDC wired to your A/C. Then you could also try to control ACC with PWM if needed.
You will just need to experiment with it and se what works.
Posted: Fri Jul 28, 2006 11:09 am
by BlackHat
Ok, actually I found out some conclusive information about my setup... I was speculating on some of it and aparantly speculating incorrectly.
The air regulator is heated by the ECU. The connector on it is NOT a sensor, but input for the electricity needed to heat up the air reg. The AAC and FICD valves are both PWM. (Actually, I also found out the AAC is 100-200hz in frequency). The other bummer, is that the FICD valve not only turns on when the A/C kicks on, but also when the AAC valve needs extra air for idling.
I'm thinking along the lines of putting a PWM valve that MSEFI can control where the Air reg is and putting the FICD valve alone on the back plate where it is now (and welding up the hole the AAC uses). That way, MSEFI can control idle during open and close loop with this new PWM and when the A/C turns on it will help load by turning on the FICD valve at the same time (so the MSEFI won't be hit by a sudden strain on the engine).
That logic sound good?
Sorry for the round and around I'm giving on the topic, some of this is thinking out loud. I appreciate how patient you've been with me. What's in this post is verified by other sources. (As far as how my 89 nissan 240sx uses Fast Idling)