Alternator went now car is hesitating..help

[Mikes06GT]

So about a week ago. Started car and sounded like had cams and volt gauge was in the red. As rpms went up so did volts and would actually shut all electronics down and as rpms came down so did volts and electronics kicked back on. I quickly shut car off. Figured volt regulator so replaced alternator. Volts are good now but car is still bogging. At start up its a little rough but smooths out. If I ease into gas seems ok. If I hit gas it misses and stutters for a sec before smoothing out and pops a little. Had tuner check data log and he saw nothing out of sorts so not thinking vacuum leak. I also swear I hear a low hum/whistle noise now that gets Higher pitch with rpms. Almost like an audio sound. Tried reloading tune but no change. Suggestions?? Thoughts? 2006 GT with just CAI UDP and tune. I was told by one guy to tap battery terminals together and keep disconnected for 20 min to reset computer.

 

[JEWC_Motorsports]

Any codes?

 

[Mikes06GT]

No codes at all. It appears as car warms up it gets better but still very much there.

 

[BruceH]

Did you also check the battery?

 

[Mikes06GT]

Battery is new also. Charge and volts are good now. Just has the sputtering. Almost like its missing

 

[dre256]

Kinda sounds like a coil pack is weak.

 

[Mikes06GT]

That's what if feels like but those are fairly new also and no codes

 

[Johnf78]

Do you still have your old ones to swap in? Maybe make sure nothing happened to them when the voltage went wacky.

 

[Mikes06GT]

No i ditched them. But maybe ill have a buddy come by and swap his in. Good idea

 

[Paps]

Spark plugs

 

[Mikes06GT]

Plugs are also new. I did plugs and coils just about 2 months ago. My buddy is coming by tomorrow and we are going to swap his coil packs on one at a time to see if that is it. Could a volt surge fry a coil pack bc im thinking thats what it is.

 

[TexasBlownV8]

You you had an over-voltage condition: wow!
Reloading the tune took care of resetting things, so no need to disconnect battery for 20 minutes (which would clear the keep-alive memory in the pcm). Not sure what the 'tap together' means, but that is not applicable anyways.

I suspect the higher voltage damaged some other component somewhere. Maybe not enough to make it fail, just yet, and therefor there is no code for it, yet.
You might try a different scanner and see if it finds any "pending" dtc's, and that may help.
Otherwise, things like COPs as mentioned are good and easy to start with. You should pull and check the plugs as suggested, too; if there was too much/too hot of a spark, it could have damaged a plug.
Could even be an injector, or fuel system. May even be a throttle controls issue, but that should throw codes pretty quickly if messed up.

I suppose you had Manuel (Lito) check over some datalogs, and he saw nothing. If it was someone else, do it with him to make sure.

 

[Ryan331]

What voltage did it reach as RPM went up?

Many things can be affected by too much power...

 

[Mikes06GT]

Yeah Lito looked at logs and said all looked ok. My buddy is coming by tomorrow so we will swap coils first, then move to tb and then ill pull plugs. It just feels like missing. As i hit gas it just sputters and then smooths out. As far as what did volts hit, not sure of number but it went into red and thats when all electronics shut down. Even gauges shut down. Once volts came down all kicked back on. Im really hoping its the coil packs.

 

[Paps]

Maybe your engine shut off a few sec that's why you saw everything off. Like texasblown said, it could be a fuel issue, especially check for fuel temp sensor or fdpm

 

[Mikes06GT]

Car itself never shut off. If not plugs or coils ill move to fuel

 

[Mikes06GT]

So I decide to run by my local shop to see if they can pick up on scanner a code that my hand held cannot. Wel they are scanning and nada but as he tells e this the volts shoot up again like they did before I replaced alternator. So at this point it appears Pcm related which sucks bc going to be tough to figure out.

 

[RocketcarX]

With the over voltage situation all the "new" electronic parts are now suspect. You can't rule out anything now without testing just because a part is recent. If it was exposed to the over voltage it's "new" status is removed.
TexasBlownV8 had some good points too.

 

[Mikes06GT]

Shop just called. They think I got a bad alternator. They did a few test and showed that this alternator was still letting 19 volts through when 3 connectors were of or something like that. Basically they said te new alternator was not working right

 

[terry5357]

I had altenators go out on my '06 but when that happened I would get a "cam position sensor" error P031 I think is what was.