A/C almost kills my Vibe at idle!

[damronjr]

If I didn't have enough problems, when I have the A/C on and I stop at a light or something, the car idles very rough (shutters and stuff on the car rattles) and tries to die. To start off with, when I start it from a cold start it won't stay running unless I hold the gas down until it is warmed up. Then, I tried to set the idle higher via the throttle cable. It seemed to work, it was idling in park at about 1400rpm which is what I wanted, so I would get the constant 14.5V from the alternator as opposed to the 11.whateverV I get at idle otherwise. I added the throttle rotor and voltage stabilizer I got from Northvibe as well when I altered the idle speed. When I started the car for the first time a few days later, it started, slowed slightly, but stayed on and idled high like I wanted. Then today I started it and it died. The ECU apparently reset the idle speed even though it was manually changed. I had to once again hold the gas until it was warm. Then (and this isn't new, just thought I'd bring it up and see what others thought) I got the A/C issue at idle. I had to turn it off to keep the car from dying at the light. It is fine when I am driving and the rpms are up, same with the airbags, a lot of times the switches won't do anything unless I step on the gas and raise the rpms to above 12-1400rpms. Any ideas? I'm guessing maybe the alternator, but it is hard to say. It is an aftermarket high output alternator, but I do have the OEM alt sitting right here and was thinking about putting it back in to see what happened.

[millster]

Well, I think a few of us have suggested ditching that alternator before when you were having problems. But I would lean more toward maybe the throttle position sensor or, if the Vibe has one, idle-air-control sensor or module.

[damronjr]

Quote, originally posted by millster »Well, I think a few of us have suggested ditching that alternator before when you were having problems. But I would lean more toward maybe the throttle position sensor or, if the Vibe has one, idle-air-control sensor or module.Yeah, and I have tried tearing apart the throttle body and cleaning all the senors before. I would hate to spend the $$$, but have thought about getting all new sensors for the TB. I will probably switch out the alternator tomorrow and see what happens as far as that gos, but with the idle being weird I'm thinking more along the lines of a sensor or something with the cars electronics.

[WaveAction]

it's probably the altenator..i had that happen in my sunfire..a few times it dipped down and idled at like 500 rpm lol but surprisingly never did die on me

[Raven]

When the A/C is switched on the car should automatically go to high idle. This is true for all vehicles I have driven. There must be a relay or something in the A/C circuit which is not engaging the high idle as it should. I don't think it has anything to do with the alternator or the regular idle setting.

[BlueCrush]

I was going to say, "Try some Seafoam", but your engine would probably explode...

[damronjr]

Quote, originally posted by BlueCrush »I was going to say, "Try some Seafoam", but your engine would probably explode... Think that'd help? I could try it, I see it at Wal-Mart all the time.Quote, originally posted by Raven »When the A/C is switched on the car should automatically go to high idle. This is true for all vehicles I have driven. There must be a relay or something in the A/C circuit which is not engaging the high idle as it should. I don't think it has anything to do with the alternator or the regular idle setting.Anybody got any more info on this relay? Might have to dig around and see what I can come up with on this.

[keithvibe]

the 14.5volt that your getting, is that with the car in gear?Are you running a scanguage to monitor the volts?

[damronjr]

Quote, originally posted by keithvibe »the 14.5volt that your getting, is that with the car in gear?Are you running a scanguage to monitor the volts?No, but I have the Voltage Stabilizer that shows a LED display of the voltage coming from the alternator. The 14.5V is in park, but with the idle higher than 1200rpms. At normal idle of 800 or so rpms it is only at 11.?V, and actuating anything other than the engine itself (i.e. A/C, stereo, airbags, etc..) brings it down fast from that.

[keithvibe]

I run a scanguage and the volts read at ALL times when i am crusing along on the road in gear 13.9volts.At start up it's reading 16. Then drops to 13.9 with my headlights onI would would see if a local advanced auto, autozone can run a test on your alternator to make sure it's working properly.