This one is a real pickle (at least to me). I REALLY hope you guys can help me diagnose this. Here's the scenario:

1. If I turn on the A/C while driving, the car begins to feel as if it's laboring. It hesitates and "hiccups" while on throttle, and just generally feels like it's not happy with the A/C on.

2. When I go into neutral (at idle or sometimes between shifts), the battery light goes off in the dash, and I notice my batt voltage drop from 13.9-14.1 to 11.3 (or something low like that).

3. This is inevitably followed by a loss of power (i.e. engine stall), and I have to restart the car (REAL fun when there's a bunch of people behind me at a light and they're all in a hurry).

Is it possible that the voltage regulator on my alternator is bad? Or could it be something else?

BTW, I have an AEM EMS, which was recently tuned. I also just added a brand new Hawker Odyssey battery (PC680), so I don't think that's it. Any help or suggestions are GREATLY appreciated!

TIA

 

hmmmmm....

Heres what I know, even on a factory ECU the A/C really labors the motor. The TPS sensor has to figure out what is going on really quickly and adapt to the extra load on the motor, and even then the RPMs will drop to 2 or 3 bars at idle.

My guess as to your problem: Your AEM EMS doesnt adapt to the extra load of the A/C. You need to have whoever tuned it, re-tune it to allow for enough idle speed to keep the motor alive on A/C. It may be as simple as setting your idle speed up a couple hundred RPMS. BUt if it is having "hiccups" on throttle, there may be more to it.

Thats just a guess.

 

Check compressor bearing. Or have it checked. Just a thought, had the same happen on a VW.
Good Luck.

 

^^ Thx for the suggestions, guys.

Going back to the tuner to see what's up...

 

I think it might be the battery. Since the issues are correlated with battery replacement, and you're showing a current drop at idle, it may be that the small battery does not have enough capacity to keep things running properly when at low engine speeds. Also, I think TJF may be onto something too. If the aftermarket ECU is not accommodating the additional compressor load, that could cause the issue. But, haven't you been running the AEM EMS without problem for a while? If so, It makes me suspect the battery even more.

 

my dodge neon did that too. it was a inline 4 it apprently happens to 4 cylinders and when i changed my battery in my dodge neon it helped alot. it stopped ####ing up

 

Yeah, the battery might seem to be the most obvious culprit. What puzzles me though is that a number of members here are running the same exact battery (incl. xviper I believe), and they are not experiencing this issue.

My plan is to have the tune re-checked and, if that doesn't work, then test with a bigger batt.

Thx guys.

 

Perhaps it is a combination of your AEM EMS and the battery. If others are successfully using the small Hawker battery with the OEM ECU, it may compensate for the energy draw of the compressor better than your aftermarket one.

IMO, the easiest way to trouble shoot this is to first borrow an OEM or equivalent battery and drive around with it to see if your problem disappears. That's easier than re-tuning the AEM, isn't it?

 

You wanna volunteer your battery this weekend?