Alternator Change - Issues Remain
 

I had a check engine light come on and checked the DTC, which had a code of PO340 (cam shaft position sensor). After reviewing this error it is known to be a bad diode in the alternator. Since this 62k 2005 GT car should not be experiencing alternator issues at this mileage AND seeing that several people have experienced the same problem I decided not to go with the Motorcraft replacement (that and Ford wanted $530, crazy bastards) and went with the PA after market due to good reviews on it. Easy install (other than one bolt on the back of the alternator bracket, left side) and the car fired up with no more check engine light. Good, I thought. But for some reason the car drops to low RPM and frequently dies on me, especially with A/C on. I took it to AutoZone to verify battery (it was only 3 months old before alternator change) and it came up with a 12.74 and the new PA alternator tested fine too. I re-tuned it and no change. This car has the Demolet tune w/Excalibur SCT and has had no issues for the 3 years it has been on the car. When you let it idle you can see small fluctuations in the power (not the normal AC kind either) and occasionally see small flickers in the interior lighting. All seems to be hooked back up good. Any clues?

Typically after disconnecting the battery (which resets the Adaptive Learning), it occassionaly takes a good 20-40 miles or so of varied driving for things to settle down.

Thanks. I will give it a few more miles and repost if issues persist.

Which PA Performance alternator did you get? If you got the 200A one, did you do the cable upgrade too? That's required for that model, optional for the 130A one.

Good question. I know I did not do a cable upgrade so assume it was the first one. All seems to work now though and alternator and charging system test well. The original problem resurfaced with low idling and dying and finally threw an error code. I wish I remembered which one but basically it was an idle code. So I cleaned out the throttle body with some WD-40 and dried it up good, cleared the code and it seems to run much better now. Someone was telling me that some places like NTB offer a full throttle body cleanout. Does anyone know if this entails anymore than what I have done (just the cleanout of the area around the flap and the flaps themselves)?

Possibly a voltage regulator problem in the alternator. If the regulator fluctuates it can cause the problems you are describing. Also low rpm surging of the engine can happen. Hope that helps. The only way to pin point that is to monitor battery voltage and current output of the alternator for fluctuations.

No issues with battery monitor, steady even when RPM's drop....

Follow up: After charging systems were tested (good) and I gave car plenty of time to do adaptive process, the car was still occasionally dying and having low idle and it finally gave off the PO506 error I stated earlier. After cleaning the throttle body the car ran better, idled better and no errors. However, after a few days of driving it started dying on deceleration and idle would drop at times but no error or check engine lights. I was reading that many users have cleaned out their IAC valve but when I called Ford on this they explained that the 05 (and up) doesn't really have that valve and it is all controlled electronically through the throttle body which is all together and has to be replaced as a unit.....one that costs $350. I gotta call BS on this. This car has 65k miles on it and needs a TB replacement? Does anyone have any info/advice on this? I DO see black electronic plastic boxes with connectors on both sides of the TB. Does anyone know if either of these serves as a type of IAC, can be cleaned,etc.. or what may be the issue here before I drive this fully insured car off a cliff? :) Thanks for any feedback or knowledge transfer....

UPDATE: For those of you who have any experience with the newer (05 and up) throttle body setup, thanks for not replying. I will hunt you down in hell for the anguish you caused me by not replying.....just kidding, but damn you. I know you are laughing but thought I would enlighten other dumbasses like myself who may attempt this in the future. For those of you who have questions on IF you should break into the black plastic sections on both sides of the 05 GT throttle body in order to check them out or possibly clean them, your answer is unequivocally NO! Do not. There is nothing under there that needs to be cleaned. It is more gears and springs systems that push the TB floats up and down and nothing in there really to be cleaned. The one on the passenger side isn't bad and can have a bit of dirt in there (not sure it affects anything) but the one on the driver side is Pandora's box. Do NOT crack into it. There are demons in there. You will be cussing like a rapper with Terets Syndrome for hours trying to get the spring assembly lined back up correctly. You will probably miss the entire Rangers vs Yankees game you had been waiting a week to see. More than likely you will not get this spring assembly lined up correctly AND will have to purchase a new throttle body from Ford as these 2 black boxes are part of the assembly and not meant to be opened. Oh yeah, and this throttle body assembly is $350 from Ford and they probably won't have it in stock. Fortunately for me, I was able to get the spring assembly back in just in time to see the Rangers lose and enjoy a bad back. Cheers.