Idle takes to long to come down in closed loop

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maych87
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Idle takes to long to come down in closed loop

Post by maych87 »

I have an aircooled porsche 911.and had a tuner shop do the tune on it but they did a bad job setting up my idle and warmup. I do not want to go back to the shop for them to adjust the idle as I dont think they know tunerstudio very well either and I cant afford to pay them anymore while they learn. I have been learning as I go and played around with the settings and have it idling fairly well once engine temp is around 200 degrees and up. I still have a couple issues for sure and want some help on the first one, which is when the RPM is coming down it goes to around 2000 rpm then takes way to long to go down to the target rpm. Its aircooled so the coolant temp sensor is actually a cylinder head temp sensor and the car is at operating temp at around 240 degrees. Attached is MSQ and Datalog
ironwill11
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Re: Idle takes to long to come down in closed loop

Post by ironwill11 »

maych87 wrote:I have an aircooled porsche 911.and had a tuner shop do the tune on it but they did a bad job setting up my idle and warmup. I do not want to go back to the shop for them to adjust the idle as I dont think they know tunerstudio very well either and I cant afford to pay them anymore while they learn. I have been learning as I go and played around with the settings and have it idling fairly well once engine temp is around 200 degrees and up. I still have a couple issues for sure and want some help on the first one, which is when the RPM is coming down it goes to around 2000 rpm then takes way to long to go down to the target rpm. Its aircooled so the coolant temp sensor is actually a cylinder head temp sensor and the car is at operating temp at around 240 degrees. Attached is MSQ and Datalog

I am working through similar things right now as well. I am running different stuff though. Have you looked at your closed loop target idle graph relating to temp? You can make the line more steep. I am sure if that is what you are referring to as your problem though.

Will
panel
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Re: Idle takes to long to come down in closed loop

Post by panel »

maych87.......I don't have an idle valve on my watercooled engine and I didn't either on my old 2275cc air-cooled Turbo engine but thought I'd have a look at your msq. Is this the area where that can be controlled from? It seems it's the only temp related thing for the idle valve control.

And your 'Idle Valve Minimum Duty (%)' is set to '0'. Should there be some number in there ?

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Dennis930
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Re: Idle takes to long to come down in closed loop

Post by Dennis930 »

maych87,

I am assuming you are using a Carrera intake manifold with the stock Bosch 2 wire idle valve. I have read in previous posts that the these idle valves do not necessarily follow a 0 - 100% pwm from close to open. You may want to check the valve operation using the test mode option in Tuner Studio. If idle does finally settle in on the correct idle RPM, then as Will mentioned, the idle RPM verses temperature table can be adjusted to get down to your desired RPM at a quicker rate. The engine will probably idle fine before the engine is fully warmed up. I am not using a CHT sensor, but I do have a thermistor bolted to Cylinder #1 cam tower. The temperatures I see when the engine is fully warmed are 140 - 160*F depending on outside temperature. But I use 125*F for the cutoff idle RPM and WUE. I am using a 75mm Mustang throttle body and Ford idle valve so I have not played with a Bosch idle valve. I have not looked at your MSQ, these are just some thoughts.
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