Can you set the desired idle RPM differently for only when the AC is on or does it have to be across the board and then it adjusts because of the load the compressor puts on the motor?
Im not a tuner @DSG2003Mach1 But i believe the answer to your question is NO.The most common cause of rough idling while the AC is on, is usually caused by a dirty throttle body. A brief initial loss of rpm as the AC comes on is normal. When the AC clutch engages to run the compressor, it places an additional load on the engine. But the car's computer (PCM) should bring the idle speed back up. Maybe @decipha can clarify on this question.Can you set the desired idle RPM differently for only when the AC is on or does it have to be across the board and then it adjusts because of the load the compressor puts on the motor?
Im not a tuner @DSG2003Mach1 But i believe the answer to your question is NO.The most common cause of rough idling while the AC is on, is usually caused by a dirty throttle body or IAC valve. A brief initial loss of rpm as the AC comes on is normal. When the AC clutch engages to run the compressor, it places an additional load on the engine. But the car's computer (PCM) should bring the idle speed back up. Maybe @decipha can clarify on this question.
Yea I know what you mean. The PCM dictates the output of the alternator as well.That’s kinda my thought, it’s really more about alternator output but trying to avoid going down that rabbit hole of info that doesn’t change the outcome of my question if ya know what I mean
Hmmm, also true, is there a way to see commanded? Never thought about that. My assumption is it just can’t keep with the load at such low rpm but I suppose crazier things have happenedYea I know what you mean. The PCM dictates the output of the alternator as well.
Hmmm, also true, is there a way to see commanded? Never thought about that. My assumption is it just can’t keep with the load at such low rpm but I suppose crazier things have happened
In Binary Editor I can add RPM to my idle when the compressor is on. EEC-V. The stock RPM added is *I think* 68 RPM…I’ll have to look tomorrow to verify.
Thanks guysyep, DNAC are the pid's that add rpm for the a/c there is also a PPM adder to kick up the iac.
The mustang didn't get alternator control from the pcm til 2005.
Sorry for the wrong info on the PCM/ Alternator control @DSG2003Mach1 . I new this happened in the mid 2000's but it didnt cross my mind to ask you what vehicle we were dealing with for this specific issue. Now that im aware this is for your 2003 Mach 1 and not your 2012 F150. Again I apoligize. If you need any help narrow this issue down dont hestitate to ask. Im assuming your rpm drop is happening when the AC is turned on and its not coming back up to a correct or high enough rpm due to the load if thats the correct issue at hand. Let me know.Thanks guys
I have a clamp meter being delivered today to try and figure out wtf is going on
It doesn’t change, desired idle rpm is always 848, never changesit kicks it up 65
log desired rpm
Transmission Range | Air Conditioning Mode |
---|---|
NEUTRAL | A/C ON |
NEUTRAL | A/C OFF |
DRIVE | A/C ON |
DRIVE | A/C OFF |
thanks @Vinnie_B
I did not think to verify that the pcm is recognizing the ac compressor being on- I believe there’s a flag for that. I’ll double check that tomorrow.
At this point by the fact that commanded idle rpm doesn’t change I’m leaning towards tuner made a boo-boo and removed the rpm kick up. As of now it appears the actual and desired rpm match… but desired isn’t changing