A/C with MS
#21
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That's fine, there has only been one released map for the MM9495 thus far. I'm driving our 95 car daily right now and I may make a tweak or two to the idle control settings based on some feedback and my testing, if so I'll post the new map and of course you could just bring those settings over. I'm not having the same issue you are though and I do think yours is likely on the map-- it will require a bit of fine tuning from car to car but I think we've got it really close. I probably put more work into the closed loop idle than anything else, it takes a bit of work to get just right. Make small changes and only one at a time, saving maps off so you can roll back if needed. And you need to test with and without the AC on. The AC will put you in a slightly different area of the map.
Notes when tuning close loop idle-- setting the reaction times too slow makes the idle valve sluggish and not react fast enough to catch the idle speed when it strays, setting it too fast makes the idle tend to oscillate. Also setting the deadband too low (trying to control the idle to too tight of a rpm range) will make it tend to oscillate. The idle settings in the MSPNP base map are very close to spot on, only minor adjustments (read: tiny increments) should be needed car to car. The maps of course need to be dialed in on a car by car basis, though they'll be close for many cars and maybe even spot-on for some near stockers.
Notes when tuning close loop idle-- setting the reaction times too slow makes the idle valve sluggish and not react fast enough to catch the idle speed when it strays, setting it too fast makes the idle tend to oscillate. Also setting the deadband too low (trying to control the idle to too tight of a rpm range) will make it tend to oscillate. The idle settings in the MSPNP base map are very close to spot on, only minor adjustments (read: tiny increments) should be needed car to car. The maps of course need to be dialed in on a car by car basis, though they'll be close for many cars and maybe even spot-on for some near stockers.
__________________
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
#22
Thanks Jerry.
I would just add that this is a very minor issue for me. I am thus far overwhelmingly pleased with the performance of the MSnS PnP and the quality of the base maps. Previous experiences with a WRXLink standalone were not half so positive. The driveability of the car is, frankly much better than I had anticipated right off the bat.
I would just add that this is a very minor issue for me. I am thus far overwhelmingly pleased with the performance of the MSnS PnP and the quality of the base maps. Previous experiences with a WRXLink standalone were not half so positive. The driveability of the car is, frankly much better than I had anticipated right off the bat.
#27
Supporting Vendor
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Join Date: Jun 2006
Location: Duluth, GA 30097
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We had to build a custom circuit to take the input from the AC and convert it to something that could control the relay for the MSPNP... I wish it was as simple as just wiring the switch straight to the relay but it wasn't. We spent a good part of the original MSPNP MM9093 development cycle designing and testing that and getting it right actually...
__________________
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Jerry a.k.a. 'FoundSoul'
DIYAutoTune.com
'91 Miata BEGi S3 GT2560 w/ MSPNP - 14.1psi - 253whp, 232wtq
'95 Miata n/a
A few other cars....
Last edited by FoundSoul; 10-19-2007 at 06:53 PM.
#28
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Location: Overland Park, Kansas
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We had to build a custom circuit to take the input from the AC and convert it to something that could control the relay for the MSPNP... I wish it was as simple as just wiring the switch straight to the relay but it wasn't. We spent a good part of the original MSPNP MM9093 development cycle designing and testing that and getting it right actually...
#30
I wanted to bring this back from the dead as I'm having a wonderful time trying to get A/C working factory smooth on a friend's '91 NA.
Here's what I've discovered with the factory ECU pinout and a my own measurements:
PIN 1S: Low (0V) when fan is in positions 2,3,4
PIN 1Q: High (+12V) when the A/C switch is pressed and the Blue light is on.
PIN 1J: A/C clutch relay: Ground this (set LOW) to engage A/C clutch and fans.
I assume the intent was this:
Only allow the a/c to run when the button is engaged (1Q) and the fan is in positions 2-4 (1S) to prevent the evaporator from icing.
Give the ecu absolute contol of PIN 1J (clutch activate) to allow for overheating, better acceleration, protection from over-speeding, anything else?
I was working on a two-transistor, 1 megasquirt output solution to the issue this weekend. My circuit was only intended to be able to shut A/C off, turning it on was the duty of the button and fan switch on the dash. So far it doesn't work. I appreciate input from any of you that have a deeper understanding.
From my own observations, 1S is 0v when you want A/C on and 1Q (the button itself) is 12V, and 1J requires 0V to GND out the relay and switch the A/C. So, if you want to bypass the ECU, minimally, you have to invert the signal from the A/C button on the dash (from 12V to 0V) and stop caring about frosting and overloading the system. How this is done with a throttle switch might need some explaining.
Here's what I've discovered with the factory ECU pinout and a my own measurements:
PIN 1S: Low (0V) when fan is in positions 2,3,4
PIN 1Q: High (+12V) when the A/C switch is pressed and the Blue light is on.
PIN 1J: A/C clutch relay: Ground this (set LOW) to engage A/C clutch and fans.
I assume the intent was this:
Only allow the a/c to run when the button is engaged (1Q) and the fan is in positions 2-4 (1S) to prevent the evaporator from icing.
Give the ecu absolute contol of PIN 1J (clutch activate) to allow for overheating, better acceleration, protection from over-speeding, anything else?
I was working on a two-transistor, 1 megasquirt output solution to the issue this weekend. My circuit was only intended to be able to shut A/C off, turning it on was the duty of the button and fan switch on the dash. So far it doesn't work. I appreciate input from any of you that have a deeper understanding.
From my own observations, 1S is 0v when you want A/C on and 1Q (the button itself) is 12V, and 1J requires 0V to GND out the relay and switch the A/C. So, if you want to bypass the ECU, minimally, you have to invert the signal from the A/C button on the dash (from 12V to 0V) and stop caring about frosting and overloading the system. How this is done with a throttle switch might need some explaining.
#31
This is how I did it. Note that the diagram there is incomplete - the whole thread's a work-in-progress but it's how I got mine working.
Rig up the pressure switch to the AC relay and the condensor fan. That was it.
Rig up the pressure switch to the AC relay and the condensor fan. That was it.
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