RPMs dip when throttle is applied and when coasting into neutral - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-31-2012, 12:02 AM   #1
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Default RPMs dip when throttle is applied and when coasting into neutral

I recently installed my MS2 DIYPNP ecu and I'm idling fine at around 800 or so RPMs. The problem is when I apply throttle, whether it be while in neutral or at takeoff from a standstill, my RPMs dip to the verge of stalling out. The same applies when I'm driving and shift into neutral, the RPMs dip to around 500-400 and bounce back to 800. I've actually stalled out a few times coming to a stop, shifting into first and applying throttle to take off. I tried playing with Dashpot Adder and other PID settings. Can anyone offer any insight? I read through through the Idle Control section of the MegaSquirt website but I don't think it helped me very much. I've included my tune for you guys to take a look at. Thanks

Oh, I forgot to mention I'm running a Garrett T25 (set for stock waste gate), 460cc injectors, GM IAT sensor/AFM delete, No TPS and stock IAC valve on a 1.6L engine.
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File Type: msq 0_Current_Miata tune_2012-07-30.msq (83.5 KB, 129 views)

Last edited by Braineack; 07-31-2012 at 04:23 PM.
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Old 07-31-2012, 01:05 AM   #2
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Do you have a datalog of the RPM dips? Is it going lean or rich when it happens?
How much (if any) autotuning have you done of your Fuel VE table? That's first and most important. Once you've got some miles of autotune complete you can check the accel enrich settings.
I had something similar, I had to play with the settings under Accel Enrich Wizard to richen mine up under throttle application.
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Old 07-31-2012, 04:21 PM   #3
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Thanks for the response SJP0tato. I noticed when I apply throttle, the RPM's will dip and I will go rich momentarily (It would drop to about 12.0 then bounce back to normal). I believe my fuel table is in decent shape. I haven't used the autotune feature, I'm using Tunerstudio and I didn't see it in there. I did notice if I turn my "close delay" to 0 in the Closed Loop Idle Valve Settings, the idle dip issue goes away completely but I end up idling around 1000-1100. Here is a picture of my VE Table and the AFR when throttle is applied.
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Old 07-31-2012, 04:24 PM   #4
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add a vtps.

tune the mapdot enrichments better

take careful look at overrun and CL idle activation settings.
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Old 07-31-2012, 06:41 PM   #5
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So for now I will just have to deal with the MAPdot until I get a variable TPS. Once I do get one, what is the ideal MAPdot vs TPSdot percentage?
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