AC idle up issue.

ducman82 · Post by **ducman82** » Tue Oct 25, 2016 3:40 pm

Hello !

So i notices my AC idle up want not functioning right. check TS and sure enough the AC "light" does not show it is active ... which is odd, i use too.

checked the wiring, using Nitrous IN. now i had to switch to Inverted, being its a 12v signal to the compressor.

after that it works!!!

BUT

even when the AC is not on, she will activate the AC idle up. starts about 5ish seconds after i start the car, and or it will turn on with the AC, but then will NOT turn off when i switch the AC off.....

thoughts?

Matt Cramer · Post by **Matt Cramer** » Wed Oct 26, 2016 6:28 am

Please enable Port Status and take a data log of what's happening.

ducman82 · Post by **ducman82** » Wed Oct 26, 2016 3:15 pm

OK done. here is a data log of the car starting... NO AC ACTIVATION and it AC idle up comes on all on its own about 5 seconds in...

just so darn odd.

Matt Cramer · Post by **Matt Cramer** » Thu Oct 27, 2016 6:56 am

The nitrous input is already inverted once, so you may be causing problems by "double inverting" it.

ducman82 · Post by **ducman82** » Thu Oct 27, 2016 3:07 pm

Where would the other "inverted" selection be? it just needs to see a 12v input.

ducman82 · Post by **ducman82** » Sat Oct 29, 2016 1:50 pm

switched it back from "inverted". getting a 12v signal to the MS box, but not turning on the AC idle up..... Hmmmmmmmmm i use to work! lol

CRSTune · Post by **CRSTune** » Sat Oct 29, 2016 6:21 pm

According to the datalog you posted, porteh is showing 71 and 87.
71=01000111
87=01010111

The first number of the binary sequence is the status of the nitrous input. 0 means the input is "off" (not receiving 12V). That's why your AC doesn't turn on. When you set it to "inverted," 0 now means "on" instead of "off" which explains why the AC now activates on it's own.

I'm curious. You mentioned that you have the ECU wired to see the compressor activation signal with MS having no direct control of the AC compressor. Is it possible that the AC compressor isn't engaging when turned on? Maybe the ECU is working just fine but your AC system isn't working correctly.

ducman82 · Post by **ducman82** » Sat Oct 29, 2016 10:13 pm

The AC works like a champ. The Nitrous in line sees 12v when the compressor is turned on via the stock button. when "not inverted", no AC idle up happens with that 12v signal. when i "Invert that" the AC Idle up kicks on with NO 12v signal (AC compressor off)..... thats the conundrum....... and has me scratching my head.

CRSTune · Post by **CRSTune** » Sat Oct 29, 2016 10:36 pm

ducman82 wrote:The AC works like a champ. The Nitrous in line sees 12v when the compressor is turned on via the stock button. when "not inverted", no AC idle up happens with that 12v signal. when i "Invert that" the AC Idle up kicks on with NO 12v signal (AC compressor off)..... thats the conundrum....... and has me scratching my head.

And you've verified that it sees 12V with a multimeter currently? Because according to the log, it's not seeing anything at all at the input.

ducman82 · Post by **ducman82** » Sun Oct 30, 2016 7:57 am

gets 12v at the engine bay. time to delve a little deeper, check the harness at the MS box.

thank you guys!

ducman82 · Post by **ducman82** » Mon Oct 31, 2016 4:18 pm

The MS box is seeing voltage......when the AC is switched on...

Hmmmmm

CRSTune · Post by **CRSTune** » Mon Oct 31, 2016 9:42 pm

It's the same thing with this log too. Porteh status is 87, meaning Nitrous IN is Off.

If you're getting 12V at the connector, maybe there's something wrong internally with that circuit.

ducman82 · Post by **ducman82** » Tue Nov 01, 2016 6:28 am

Ya, thats what i am thinking...........

now to see how i can figure that out.

ducman82 · Post by **ducman82** » Sat Nov 05, 2016 2:19 pm

Well I'm getting current all the way to the connector, no drop in voltage to MS box.

now to open the box and check. which is odd being i changed nothing other than software updates..... Urg.

anyone know where one traces the input on the boards? what to look for what could be wrong? (nitrous in)

Matt Cramer · Post by **Matt Cramer** » Mon Nov 07, 2016 8:41 am

What MS2 variant is this?

93supercoupe · Post by **93supercoupe** » Mon Nov 07, 2016 9:13 am

Ive had problems with nirtous IN just like this. Just stopped working (actually using nitrous)

Ultimately i had to switch inputs

ducman82 · Post by **ducman82** » Mon Nov 07, 2016 12:40 pm

Matt Cramer wrote:What MS2 variant is this?

Ms3X.

ducman82 · Post by **ducman82** » Mon Nov 07, 2016 12:59 pm

93supercoupe wrote:Ive had problems with nirtous IN just like this. Just stopped working (actually using nitrous)

Ultimately i had to switch inputs

ya it worked on day... then just stopped...

Matt Cramer · Post by **Matt Cramer** » Mon Nov 07, 2016 2:12 pm

Sorry, thought I was in the wrong forum. I have seen the 12 volt input get damaged if it is wired to a relay coil or solenoid.

ducman82 · Post by **ducman82** » Mon Nov 07, 2016 3:21 pm

Matt Cramer wrote:Sorry, thought I was in the wrong forum. I have seen the 12 volt input get damaged if it is wired to a relay coil or solenoid.

i get the signal off the 12v that goes to the compressor.......... how can one fix that, or tell if it is damaged?

how could i wire up a "ground switch" input for this compressor ? maybe off the relay or something? i dont see any other 12v switched inputs

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