Megasquirt Questions
Discussion
Quick question for you guys running Megasquirt, I managed to get the stepper working properly today and the car idling nicely but tomorrows job is to sort out the warm up enrichment and stepper controls during warmup. Do any of you guys have a pic of your graphs to see if i am roughly in the right ballpark? 
Cheers,
Cheers,
Managed to get somewhere today but will need a few more goes before it is perfect i should imagine, so will have another go tonight when the car is cold again. The only real problem i am coming across is that even though the stepper is fully closed it is hot idling around 1200rpm, so i think the throttle may be held slightly open on the screw.
Problem is that if I adjust the throttle stop will that knock off the rest of the map?
Problem is that if I adjust the throttle stop will that knock off the rest of the map?
Sardonicus said:
Use the plenum air bleed screw, don't use the stop or you will be calibrating the TPS again and you should not have to move the stop anyways.
I tried that but i ended up having to throttle it back so far that there was not enough air with the stepper fully open for cold starting. To get the idle down to around 850rpm warm it was almost fully closed. I will try again tomorrow though incase i have made a mistake.Sardonicus said:
Are you sure the stepper is not functioning back to front it's easy to get the wiring reversed, there is a stepper test mode in Tunerstudio to confirm.
Yes i had the housing off the car with the stepper make sure i knew how many steps it needed to fully close and fully open, which i did in test mode. I will double check that later though by telling it to open the stepper when warm and check that the revs rise.It have got it to tick over nicely from cold and warm its just the actual idle speed is too high and ive run out of adjustment
AceOfHearts said:
Had a break through tonight. Looks like the throttle bypass was screwed down too far and the stepper motor is working back to front. Once I found this I have sorted the hot idle and adjusted the graph the right way for the cold idle so i can fine tune that tomorrow
well done, enjoyable stuff int it?Belle427 said:
Im also having a few stepper related issues and am wondering if its wired back to front.
Can you drive the stepper open and closed with it out of the plenum to verify direction?
Mine was originally wired in the wrong way and i swapped the wiring over at the stepper plug. with the later firmware you can change the homing direction from tunerstudio, so there should be no need to change the wiring.Can you drive the stepper open and closed with it out of the plenum to verify direction?
The stepper should extend to the fully closed position when the ignition is switched on and then retract to the cranking position. ideally the homing steps should ensure that the stepper is fully closed against the stepper housing to get a reference point to work from. If its wired back to front, it will fully open initially, i.e. fully retracted, and then extend to the cranking position. Mine was set up like this for quite a while, and it works to a point, as long as the AC stepper warm up curve was reversed. However, it don't think its as reliable in this mode as the reference point isn't as consistent.
Its possible to check this with the stepper removed and wired up. just turn on the ignition and check which direction the stepper moves. Beware though, that if its set up correctly the pin will fully unscrew from the housing and fire into the engine bay somewhere, so make sure you have something to catch it. alternatively you can just adjust the curve and see which way it moves, or use the test mode in tunerstudio.
Great thanks.
I used that test page and I think I'm happy it's wired correctly.
I set it to 200 steps, homed it and it fully extended the pintle and sealed off the air passage.
Also displayed zero on the gauge.
I found it easier to remove it from the plenum and watch it/blow through the port to check.
Did you set up your base idle speed on the Megasquirt as per the 14cux system?
I used that test page and I think I'm happy it's wired correctly.
I set it to 200 steps, homed it and it fully extended the pintle and sealed off the air passage.
Also displayed zero on the gauge.
I found it easier to remove it from the plenum and watch it/blow through the port to check.
Did you set up your base idle speed on the Megasquirt as per the 14cux system?
Edited by Belle427 on Friday 27th September 07:16
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