Idle Solenoid Frequency?

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mrx79
Experienced MS/Extra'er
Posts: 299
Joined: Wed Oct 29, 2008 8:26 am
Location: Frankfurt / Germany

Idle Solenoid Frequency?

Post by mrx79 »

Hallo,
i would like to know which Frequency you operate your PWM Idle valve at?

Mine is a stock '91 Honda EACV solenoid and i have a struggle between resonance noise and linearity/sensitivity of the valve.
I did two tests, one at 12Hz (just to see what is possible) and one with 204Hz (highest frequency which is barely audiable - resonance noise in intake manifold wise).

Here is the idle rpm vs. DC plot for 12Hz:
Image

and here for 204Hz:
Image
Note the big jump with two plateaus at around 75% DC, here the solenoid seems to have a big nonlinearity step at this freq.
Everything higher in Freq. is not audiable but even worse with linearity and idle is very hard to control with it.

What would you recommend?
From what i could find out on the net, Honda seems to control is around 300Hz with the stock ECU.
Location and intake manifold is stock.
Honda CRX B16A1 Turbo | MS3 running | pre1.5.1 beta7 Firmware | 24/1 Dual Wheel | COP ignition | 725cc ID injectors
jsmcortina
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Re: Idle Solenoid Frequency?

Post by jsmcortina »

How is the idle valve wired? Do you have a recirculation diode in place?

James
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mrx79
Experienced MS/Extra'er
Posts: 299
Joined: Wed Oct 29, 2008 8:26 am
Location: Frankfurt / Germany

Re: Idle Solenoid Frequency?

Post by mrx79 »

jsmcortina wrote:How is the idle valve wired? Do you have a recirculation diode in place?
Hi James,
you are right, i missed the diode to 12v. :o i missed the part in the manual :RTFM:

I will add one and retest the behaviour at higher frequencies.

Thanks
Honda CRX B16A1 Turbo | MS3 running | pre1.5.1 beta7 Firmware | 24/1 Dual Wheel | COP ignition | 725cc ID injectors
mrx79
Experienced MS/Extra'er
Posts: 299
Joined: Wed Oct 29, 2008 8:26 am
Location: Frankfurt / Germany

Re: Idle Solenoid Frequency?

Post by mrx79 »

Hallo James,
just want to give a small feedback and say thank you for your hint concerning the diode.
In fact the linearity at higher frequencies improved after installing the diode.
But much more important, at ANY frequency, my resonance noise completely vanished. :yeah!:

In the end i kept the 12Hz setting, as it gave me the most linear response over a wide duty cycle range without noise.
But anyway, i could use all other freq. as well if i wanted.

I assume that the solenoid kept sticking when turning off, especialy at high freq. which also caused the resonance noise on the intake duct.

So everything fine now... again thanks for your hint. I'am very happy ;-)

Best regards
Honda CRX B16A1 Turbo | MS3 running | pre1.5.1 beta7 Firmware | 24/1 Dual Wheel | COP ignition | 725cc ID injectors
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