# Controller/Pump/Solenoid questions



## SDM (Aug 9, 2007)

These questions relate to the typical Snow or DO w/m setup:
Q1. What type of signal from the Controller activates the pump, is it a varying duty-cycle (digital in nature) or is it analog (varying voltage).
Q2. If the answer to Q1 is 'duty-cycle' then how does the solenoid, when used, respond to this signal since it uses the same source, is it quick to turn on and slow to turn off to avoid 'chatter'?
Q3. Finally, can these typical pumps be wired 'permanently on' with the flow of w/m being switched on/off by controllers/solenoids or would this cause the pump to overheat etc.


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## theAntiRiced (May 7, 2005)

*FV-QR*

1) Typically they are either MAP or MAF based.
2) The solenoid is best powered off the same line going to the pump. They are very fast to open.
3) The pump is powered from the controller or a relay activated by the controller. The pumps are often identical to what you'd have in an RV to shower with, so you don't need to worry about overworking it.


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## SDM (Aug 9, 2007)

*Re: FV-QR (theAntiRiced)*

Thanks for feedback.
With regards to Q1 I'm trying to find out what the ouput signal from the Controller to the pump looks like. 
From what I can gather it is a variable duty cycle, either on(12V) or off(0V) of varying ratio according to the MAF/Map signal.
That got me to Q2 were I was trying to understand how the solenoid responds to this signal since like you say the pump and the solenoid are fed the same signal from the Controller. The solenoid must react quickly to the (12V) signal and not react to the (0V) as quickly, otherwise w/m flow would be interupted all the time while in boost.
I have an electronics background and am playing with an idea for the 2.0T FSI carbon build-up problem :
http://www.golfmkv.com/forums/...97244


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