FULL 3.5 Swap A/C issues, Anyone else?
05-13-2008, 02:26 PM
#1
FULL 3.5 Swap A/C issues, Anyone else?
Well, having a bit of an issue with my A/C in my full swapped Maxima. Nismology prob remembers this discussion, so jump in anytime man! And anyone here who has experience with their full 3.5 swap, please chime in, either contrary or likewise to my experience.
Basically, the symptom is: The A/C works fine until I romp the car. I lose the ACRLY GND output from the A33B ECU, and to get my AC going again I need to restart the car. I believe the A33B ECU needs to "reboot" to forgive whatever it disliked about my setup and my driving habits.
Here's the deal: I am using the A32 AC system with the A33B ECU.
AC Signal goes like this: GND thru Fan speed 1-4, GND thru A/C or DEF switch, GND thru Triple Pressure switch into pin F48-45 of the A33B ECU. Pin F48-21 applies GND to the A32 AC Relay. Pin F48-30 is not connected (more on this later). I have a pair of 10K resistors simulating the A33B pressure sensor, applying 2.5V into F48-81 of the A33B ECU.
So, Nismology and I concluded to some extent that the ACPDCUT F48-30 prob goes low when the A33B ECU detects some reason (say, high revs or Refrigerant Pressure Sensor fault) to ask the A/C controller in the A33B to turn off the COMP/ARCON signal. BUT, I tested this pin the other day. It stays at GND at all times, idle, WOT, redline, etc. So, I am not going to be able to implement the ACPDCUT like was suggested previously. To do that would require installing the A33B Refrigerant Pressure Sensor, which is part of the AC line and I don't want to crack open my AC system (maybe in the future if it ever needs repair I will consider installing a A33B AC line and wiring everything back to "normal"). And of course, my A32 HVAC controller has no ACPDCUT input and I'd need a relay to break the ARCON line anyways.
So, I plan on installing the Summit RPM switch that is so popular for the MEVI guys and using that to cut the ARCON signal to the A33B ECU, and I plan on bypassing the A33B ECU ACRLY output and just run the ARCON from the RPM switch (thru a relay of course) directly to the ACRLY. Basically, the A33B ECU will still see the call for AC (to maintain good idle quality), but will no longer be able to control the ACRLY. The RPM switch will be set to somewhere between 3500 to 4000 RPMs to deactivate the ACRLY during higher revs, protecting the AC Compressor and avoiding the cut-out of the triple pressure switch which could cut back in at higher revs and cause stress to the AC Compressor and AC system.
Also, no codes currently from OBD-II regarding AC system issues with the ECU.
I just wanted to put this out there and let the experienced guys tell me if I am wrong somewhere before I go buying parts and modifying the car's wiring. So, tell me what ya'll think....
Basically, the symptom is: The A/C works fine until I romp the car. I lose the ACRLY GND output from the A33B ECU, and to get my AC going again I need to restart the car. I believe the A33B ECU needs to "reboot" to forgive whatever it disliked about my setup and my driving habits.
Here's the deal: I am using the A32 AC system with the A33B ECU.
AC Signal goes like this: GND thru Fan speed 1-4, GND thru A/C or DEF switch, GND thru Triple Pressure switch into pin F48-45 of the A33B ECU. Pin F48-21 applies GND to the A32 AC Relay. Pin F48-30 is not connected (more on this later). I have a pair of 10K resistors simulating the A33B pressure sensor, applying 2.5V into F48-81 of the A33B ECU.
So, Nismology and I concluded to some extent that the ACPDCUT F48-30 prob goes low when the A33B ECU detects some reason (say, high revs or Refrigerant Pressure Sensor fault) to ask the A/C controller in the A33B to turn off the COMP/ARCON signal. BUT, I tested this pin the other day. It stays at GND at all times, idle, WOT, redline, etc. So, I am not going to be able to implement the ACPDCUT like was suggested previously. To do that would require installing the A33B Refrigerant Pressure Sensor, which is part of the AC line and I don't want to crack open my AC system (maybe in the future if it ever needs repair I will consider installing a A33B AC line and wiring everything back to "normal"). And of course, my A32 HVAC controller has no ACPDCUT input and I'd need a relay to break the ARCON line anyways.
So, I plan on installing the Summit RPM switch that is so popular for the MEVI guys and using that to cut the ARCON signal to the A33B ECU, and I plan on bypassing the A33B ECU ACRLY output and just run the ARCON from the RPM switch (thru a relay of course) directly to the ACRLY. Basically, the A33B ECU will still see the call for AC (to maintain good idle quality), but will no longer be able to control the ACRLY. The RPM switch will be set to somewhere between 3500 to 4000 RPMs to deactivate the ACRLY during higher revs, protecting the AC Compressor and avoiding the cut-out of the triple pressure switch which could cut back in at higher revs and cause stress to the AC Compressor and AC system.
Also, no codes currently from OBD-II regarding AC system issues with the ECU.
I just wanted to put this out there and let the experienced guys tell me if I am wrong somewhere before I go buying parts and modifying the car's wiring. So, tell me what ya'll think....
Last edited by made in china; 05-13-2008 at 02:30 PM.
12-17-2008, 10:04 AM
#3
everytime i see these full 3.5 swaps i gotta give u guys props...... i just got done doing the regular swap and the 5 speed swap at the same time and i had enough.. lol
but good luck w ur troubles.. keep us posted
but good luck w ur troubles.. keep us posted
02-14-2011, 09:16 PM
#6
I know you were going for a relatively "stock" 3.5 swap (no mods...just plain reliability). Is this the only thing you were not able to get back to "stock" working conditions after you did your full swap?
02-14-2011, 09:43 PM
#7
The cruise doesn't work. My CAN system is reporting a missing ABS and VDC line, which my car had neither. I think those errors prevent the cruise from working. I even installed the resistors and get the correct values, but my cruise light just flashes when I try and use it.
No biggie. I just did a 5K mile road trip from WA through the west coast to AZ and never missed the cruise or had probs with my A/C setup.
Passes emissions every year perfectly! And no other "probs". I've put 80K miles on the swap.
No biggie. I just did a 5K mile road trip from WA through the west coast to AZ and never missed the cruise or had probs with my A/C setup.
Passes emissions every year perfectly! And no other "probs". I've put 80K miles on the swap.
02-14-2011, 09:59 PM
#8
Thats cool...I can live with that... I pulled the ac condensor and related sensor from the car I got my engine from in hopes I might be able to fab the bung and sensor into my 4th gen condensor and get around the AC issue. But upon further inspection it looks like there might be a bit more involved than this....I will just have to not floor it.
02-16-2011, 07:02 PM
#9
Thats cool...I can live with that... I pulled the ac condensor and related sensor from the car I got my engine from in hopes I might be able to fab the bung and sensor into my 4th gen condensor and get around the AC issue. But upon further inspection it looks like there might be a bit more involved than this....I will just have to not floor it.
If I ever got around to it, I would replace my A/C high side line with the one from the A33B so I could use the A33B sensor. But since my stock AC works perfectly, I'm not going to touch it until it needs service.
02-16-2011, 11:27 PM
#10
The A/C pressure sensor that's in the A/C line needs to be changed (actually I think the entire high side line needs to be replaced as the A33B sensor won't fit in the A32 line). In the A32, it's a 2 stage pressure switch. In the A33B it is an actual sensor, not a switch. The A32 setup doesn't work with the A33B ECU. As long as I keep my foot off the WOT, the A33B ECU doesn't seem to mind that my A/C pressure sensor is missing.
If I ever got around to it, I would replace my A/C high side line with the one from the A33B so I could use the A33B sensor. But since my stock AC works perfectly, I'm not going to touch it until it needs service.
If I ever got around to it, I would replace my A/C high side line with the one from the A33B so I could use the A33B sensor. But since my stock AC works perfectly, I'm not going to touch it until it needs service.
About the cruise control. If the big problem is with the switch, why not just change out the steering wheel and switch and run the wiring to the wheel like in the a33?
02-17-2011, 07:32 PM
#11
My switch is modified to work the same as an A33B switch. My problem is that the ECU is popping codes for missing ABS and VSC(sp?) which I'd have to retrofit newer ABS system into my car to clear those two codes. I reckon those codes are enough to prevent the cruise from operating.
02-17-2011, 08:49 PM
#12
My switch is modified to work the same as an A33B switch. My problem is that the ECU is popping codes for missing ABS and VSC(sp?) which I'd have to retrofit newer ABS system into my car to clear those two codes. I reckon those codes are enough to prevent the cruise from operating.
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