Thread: Won't idle
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Old 12-03-2021, 10:25 PM   #3
142 guy
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Join Date: May 2014
Location: Saskatchewan, Canada
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Its not the cause of your problem; but, what frequency are you running? 92 hz seems to be the best setting for the Bosch 2 and 3 wire valves.

What have you got your warm PW set at for the valve? On my Bosch 2 wire valve, the valve is open at 0% and goes closed about 25% and then re opens around 40% going to full open around 70% - 90% PW. The normal practise is to have it operate in the 40% to 90% PW region. The 2 wire valve is voltage sensitive. The % values for open and close change with operating voltage so if 45% is open with the engine running and good voltage it may not be open during cranking when the voltage is low. You need to program the voltage sensitivity into Tuner Studio. If you have the three wire Bosch valve the positions are insensitive to the operating voltage.

You need to pull the idle valve off the car and look into the ports as you run the idle valve using the idle valve output test function in Tuner Studio. As you vary the PW you should be able to see the valve go open and confirm the start of opening and full opening % values. Yours may not match up with mine.

Tuning closed loop idle takes a lot of work. Start off using open loop. If you still have a mechanical air by-pass, use it to set a base warm idle speed. Get the rest of your tune and configuration settings into a reasonable state and then you can set the idle PW versus temperature curve for the idle valve to give you a good cold idle speed for warm up. If you have ignition control I suggest that you implement the idle advance function to help stabilize the idle speed. At the point that you have your tune perfect and a good configuration you can take a crack at trying to make closed loop idle control work.

Call back in a few months to tell us how it is going. While you are working on it, poke yourself in the eye with a stick so that you know there is something more painful than trying to perfect closed loop idle.
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