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Cold Start and Idle (CL+IGN Control)


wastegate

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Hi Everybody,

I'm in need of a little advice, trying to get my cold start and idle sorted.

Engine is a 2JZGTE VVTI with 272 Cams. Starts okish, just takes a few cranks, when it starts, the idle settles to 700-800rpm and is a bit cranky. Until the engine get warmer (over 40c) where it smooths out.

However, I have set the target RPM to 1300 for colder temps, but it never get to that.

I have Closed Loop enabled, I also have IGN control turned on with max advance 20 degrees. After start, the idle goes to 800rpm, and IGN is at 12 degrees, then about a couple of seconds, IGN control kicks in and pushes the IGN to 20 degrees to try and meet target, however all this does is drops the rpm about 100rpm then kinda goes up then down. Starts to smooth out once engine starts warming up.

I've captured a PC log of the cold start and tune file.

Log
https://drive.google.com/file/d/1ULMaLkHUhJiwwCnNxeLiLMFNIS-v-wfo/view?usp=sharing

MAP
https://drive.google.com/file/d/1Ud05ODTCVPjJLFeana5_2_wK-5VSMb9x/view?usp=sharing

I've tried to change the base position table from say 5 to 7.5 but doesn't seem to do anything. What am I missing here? Is it a fueling thing? Too much fuel during startup? Lambda is not enabled until 15 secs or so after and it's very rich. But if it's not rich, the idle is very lumpy.

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I have made a couple of changes in the map attached below.  Increased integral on the E-throttle set-up as you had very little so it wasnt following target well.  Unfortunately air con was on in that log so not sure how close the base position is.  But should be closer now.  You may need a bit more start up offset if it doesnt reach correct RPM (or overshoot a bit) right away.

Nicks G4X 06-03-2022 Tweaks 1.pclx

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Thanks Adam, seems to have helped! Idle settles on target nicely (as much as cams can). 

I have a side question.

Should my Throttle be resting at 5% while at speed under decel (or <5% APS). Idle I understand but no matter what the car is doing, cruising at 100kph or around the street, the TPS always shows minimum of ~5%. I would have thought during a decel event, TPS should be fully closed? 

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Outside of idle conditions the throttle will go to whatever is in your E-throttle target table + idle base pos + dashpot offset.  If it went to zero during decel as soon as the RPM got low enough for idle control to engage there would be no air in the plenum and throttle is closed so the engine would stall as soon as you press the clutch in. 

You would normally have 0 right across the top row in your E-throttle target table, I noticed you have 3% above 2000rpm so that will hold it open even more.  

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