For some reason, the idle on my car will dip down when I turn on accessories like my head lights, raise/lower the power windows, electric fans kick on, or putting the top up & down. It’s a real pain as sometimes my car will stall.

It is not uncommon for the motor to stall when I am putting the top up. This is very frustrating as I don't like to turn the car off this way and leave the battery in a drained state.

Not sure if it is the battery (1.5 yrs old - stock size), alternator, AP1 flywheel weight (14lbs), Vortech supercharger (extra engine load), or my AEM v2 EMS tune.

By the way, after several cleanings & issues with my old IAC valve, I replaced it with a new one about 1000 miles ago. It idles great now except for the problems mentioned above.

The battery always has a good charge and no issues with starting (especially now with only 10:1 compression). I don’t have the issue when the AC comes on because my tuner bumped up the idle when the AC compressor kicks on.

I am planning on doing some testing with my volt ohm meter to see voltage changes at the battery when idling in the garage & high load electrical items are turned on. Just thought I would post this to see if anyone has any experience with this so I can avoid a lot of trial & error.

Thanks for any help or suggestions if you have had experience with this.

 

I had the same issue, but mine was worst when ac comp/fans kicked on. It never made me stall out, but I def would go down to 500 or so. I had a scan gauge hooked up for awhile, so I could see the voltage dropping into the low 12v's every time the above mentioned would kick on. Replaced my battery and everything has been great since. It even fixed my idle issue.

So yeah, I think you're on the right track. Hook a voltage meter up to it and see where that puts you.

 

Thanks MR.T. I was wondering if I needed a battery with better storage capacity. Do you happen to know what battery (size, amps, etc) you put in your car that fixed the problem?

 

Oh, I forgot to mention. My tuner bumped up the idle (~200 rpms or so) in the EMS (AEMv2) when the AC turns on. That part works great. I just don't think he can do that when I turn on all the other items.