Stalling issues.... Tune or something else?

[GTA_V6_Mustang]

Ok well I have been having this issue with the stang for a while. I am pretty sure its related to obvious engine mods H/C/I but am curious if a proper tune will help it or not. With the A/C on it will just turn off sometimes. Like I will turn the car on and let it warm up and if I turn the a/c on it will idle fine for a bit then the idle will start to fluctuate and it will eventually turn off. And if I am driving and am using the a/c I will come to a stop sometimes and it will just turn off when I come to a stop with no warning. But if the A/C is off I can drive it all day long no problems. Beat the living crap out of it no problem and idle it forever no problem. I do have a diablosport chip with an off the shelf tune for my cam specs and so forth. But do you think with a proper dyno tune they may be able to take care of this issue for good. Last time I had it on the dyno we actually checked A/f while it was doing the idle fluctuation before it cuts off and it would go from 9:1 idleing like real low up to 18:1 idleing smooth then down to 9:1 and idle goes str8 down and back and forth till it dies. Is there anything I could do either then tune it to fix this?

 

[toyman]

Ok well I have been having this issue with the stang for a while. I am pretty sure its related to obvious engine mods H/C/I but am curious if a proper tune will help it or not. With the A/C on it will just turn off sometimes. Like I will turn the car on and let it warm up and if I turn the a/c on it will idle fine for a bit then the idle will start to fluctuate and it will eventually turn off. And if I am driving and am using the a/c I will come to a stop sometimes and it will just turn off when I come to a stop with no warning. But if the A/C is off I can drive it all day long no problems. Beat the living crap out of it no problem and idle it forever no problem. I do have a diablosport chip with an off the shelf tune for my cam specs and so forth. But do you think with a proper dyno tune they may be able to take care of this issue for good. Last time I had it on the dyno we actually checked A/f while it was doing the idle fluctuation before it cuts off and it would go from 9:1 idleing like real low up to 18:1 idleing smooth then down to 9:1 and idle goes str8 down and back and forth till it dies. Is there anything I could do either then tune it to fix this?

How is the A/C working otherwise? A failing compressor could be adding so much drag that it is stalling the engine. Not saying it isn't a tuning issue but it could have a different source for the problem. I believe the swing in the AFR is probably normal in closed loop with a fluctuating idle as the EMS tries to stabilize the idle speed.

 

[GTA_V6_Mustang]

How is the A/C working otherwise? A failing compressor could be adding so much drag that it is stalling the engine. Not saying it isn't a tuning issue but it could have a different source for the problem. I believe the swing in the AFR is probably normal in closed loop with a fluctuating idle as the EMS tries to stabilize the idle speed.

Naa the a/c works great. Besides the car itself has barely 30k miles on it so I doubt there is any component that is a problem.

 

[HISSIN50]

How is the cold idle? Can you tell if your IAC is functioning properly (knowing if it functions as a choke can help one infer if it is functioning for the AC and dashpot).

 

[GTA_V6_Mustang]

How is the cold idle? Can you tell if your IAC is functioning properly (knowing if it functions as a choke can help one infer if it is functioning for the AC and dashpot).

Well the car idles great all around. It only acts up with the A/c on. When I turn the a/c on the idle reacts accordingly adjusting itself but it will just suddenly start to surge then shut off. Or as I am driving it will just shut off sometimes when coming to a stop.

 

[GTA_V6_Mustang]

ok well update. I used the smoke machine that we use to find EVAP system leak which works great to find vacuum leaks also and I had a vacuum leak through the actual tps shaft so i ended up putting an o-ring on the tps and tested it again no leak. But dont know if that fixed the idle problem with the a/c but it is idleing much better even with the cam and all. When it warms up again I will see what happens.