For anything you'd like to see added to Speeduino
By 92Yata
I am running a speedyefi with firmware 202207.01 in my 1992 turbo 1,8 miata.
I am not a tuner nor a coder but have been dealing with heatsoak engine starts that are not IAC related.
Using the crank to run taper in open loop is beneficial here.
I believe the megasquirt ecu has this feature in closed loop.

It would be great to have the crank to run taper available in the closed loop to help compat this issue while still having the benefits of better idle control.

Is there anyone that can code this into the firmware?
User avatar
Investigative questions only for background info:
  • What is the source of the heat-soak issue in your setup?
  • Has the issue been approached from the source of the issue?
  • If this is not IAC related, why address it with IAC?
  • Can you post a log of the issue and your tune to review?
By 92Yata
I did not write this correctly. I should have said it is not IAT related as this seems like a common issue.
My apologies.
I started with one tuner who could not resolve the heatsoaked startup.
Then another tuner insisted it was heatsoaked injectors and I needed to use ASE to give more fuel when hot.
This did work but was not ideal.
Then I finally found another tuner who has fixed all my issues.
He told me this heatsoak injector theory is not a thing and I should not be using the ASE to correct.
Despite me finding many posts with regards to this.
He did solve my start up issue but needed to revert back to open loop idle to get functionality of the crank to run taper.
Currently using 17 sec.
He told me the MS has this in the closed loop idle as well.
Thought it would nice to have this with the speeduino as well.
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User avatar
Possibly, but there may be other ways to correct for either real heat-soak, or indicated heat-soak. A taper is one possible solution, and there are others we can consider that may serve you better. Please post your tune and a log with the issue, and of "normal" idle running, for review of the issue. A screenshot does not show us some things we would look at. ;)
By 92Yata
So I do have good cold and hot starts.
The problem was when the car was hot and then sat for some time 10-15 minutes it would start up and then just die.
If I worked the throttle for 30 sec or more it engine would then maintain idle.
Engine would start and run lean until the cool fuel cooled the injectors I suspected.
Not sure if that is the case or not.
I was using the ASE to ramp up more fuel when hot and did work but then the engine would run rich if I started the car immediately when hot.
Idle was much smoother when setup using pwm closed+open idle control.
The need for the crank to run taper was needed for this engine for the heatsoaked restarts if in fact its a heatsoaked issue?
So reverting back to pwm open cloop idle control was necessary to gain functionality of the crank to run taper.
I have noticed the idle is not as refined now though.
Again it would be great to have the crank to run taper available in the pwm closed+open idle control mode.
Here is my current tune with the closed+loop idle control and a log of the heatsoaked restart.
I will also include my open loop map and a short driving log.
I think I have the correct logs of the startup events uploaded from when I was using open+closed loop.
At some point we started experimenting so I believe I have the correct maps uploaded.
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Last edited by 92Yata on Thu Jun 01, 2023 9:43 am, edited 2 times in total.
By 92Yata
A few more specifics of the car.
It is a 92 Miata with a stock 1.8 engine swap.
Kraken Turbo kit with T25 Garret Gt2560r + 3" exhaust
Bosch EV14 700cc injectors
Sequential injection
Toyota COP
Speedyefi ECU
Stock fuel system with the return and new Dw fuel pump
NGK BKR7E plugs gapped to 0.024
By Ilotalo
I was tuning my car today. I got this newest firmware 202305. I noticed this same thing. When engine is warm this closed+open loop is way too aggressive. It closes that valve too fast and then engine dies.

I'll check this out.
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