Sneeze2K

Hi guys,

I'm having an issue with my 2005 (80k miles). I was recently tuned with AEM Series 2 by a professional tuner and i've noticed when sitting in traffic with the a/c on that the idle seems to fluctuate and shudder every 30 seconds or so (even stalled once). After looking into the issue I found that the idle goes wacky any time an accessory draws current from the battery such as when the radiator fan switches on or the window motor or headlights are activated. I was told this was likely a bad alternator but I got the alternator checked and everything came out fine (Battery voltage will drop from 14.4V to 13.8V and recover). I have had the tuner look into it but he could not correct the issue by messing with the tune. Anybody else run into a similar issue or have any ideas?

UPDATE: I found through more research that the primary injector battery offset table needs to be adjusted in AEM to fix a lean condition with voltage drop. Anybody know how it should be adjusted with stock injectors?

Thanks!

cleenyc99

do you have an idle control map? sounds like something with the iac to me ether mechanical like a dirty valve or some thing with the control side in the map. just a thought.

superchargedk20

Set the idle higher so it doesn't drop so much when something is turned on. I just got tuned too and when the fans come on the drops rpms too but not to the point of shutting off

Sneeze2K

didn't want to do it but i guess i'm going to have to try setting the idle target 100 rpm higher while the radiator fan is on and see if that helps. stay tuned

superchargedk20

What are u idling at now? Pretty sure mine is at around 958

Sneeze2K

before i had the idle target set at 1000 and now i have it at 1100 while the cooling fan is on and it seems to have helped with the shuddering. still seems odd i would need to do that... i think adjusting the primary injector battery offset would help but i dont know how to adjust it. might make a new thread about it in the tuning forum

superchargedk20

I don't remember if my tuner messed with that. But I'll tell u 1 downside I had. Everytime an accessory turned on my car af went to 16.0. Pretty lean for idle. He couldn't get me at a good 14.7 when the fans came on. I'm at 13.7 at idle now. And when the fans kick on I'm at 14.7

cleenyc99

you should have to adj the injector battery offset. you set it to what the inj call for and your done. I no you changed the idle target from 1000 to 1100 but what does the car actually idle at with the acc off

Sneeze2K

it idles right at the target until an accessory switches then it will drop down to 900 and shudder a little bit and correct itself. then when the acc switches off the idle will surge to 1600 for a second and then stabilize at the target idle

superchargedk20

By setting this now to the 360cc injectors will it change any of the fuel settings at normal idle?