Voltage issue-need assistance

[BlueDevil]

I have been having an intermittent voltage issue recently. The video is short, but you can see what's happening. It only happens at idle (it's a 2006 GT 5 speed). If you have the volume turned up, you can hear the fans on my Afco h/e speeding up and slowing down as the voltage rises and falls.
IT"S IMPORTANT TO REITERATE that this voltage issue ONLY happens at idle. With any throttle input (revving, driving) the voltage is right where it should be (stock gauge, slightly to the right of center, or roughly 13.5-14 V).



Relevant information:
* Alternator is PA 200 amp, and is only a few months old. I have a 4 gauge alternator wire to the battery, and a 2 gauge ground cable going from the motor mount to the sway bar mount. It's been fine up until recently.
* Advance auto parts tested the battery/alternator (in the car, during startup and while running), and said alternator is fine, but battery has lower cranking amps than advertised (3 years old, 530 cca vs 580 advertised cca). They recommended a new battery.
* My tuner tested alternator and didn't see any problem, but at that point, just like in the old joke, my voltage refused to bounce around, and we got nowhere. I feel like we would have seen something had the voltage been rising and falling, but the car decided to act normal that day.
* I have had some throttle body gremlins in the past, and my tuner said it might be due to the fact that my TB motor harness was pinched between the battery and TB. I replaced the harness with a Motorcraft repair harness (soldered and heat shrunk), and modified the battery tray in order to move the battery away from TB harness. This has reduced the amount of my voltage issue, but not eliminated it. It's random now (still ONLY at idle, but not all the time).
*See this thread for harness back story: http://www.s197forum.com/forum/showthread.php?t=114119

I appreciate any help you can give!

 

[eighty6gt]

Replace the battery and alternator with new Ford parts.

 

[toorbeenee]

Check your SJB, could be wet there.

 

[Kylar]

Recheck all your connections to the batt and alt, also sounds like you should get a new batt anyways. Mind as well do that to reduce that as a possible cause.

 

[AutoXRacer]

I had a similar issue when I first tried a PA alternator last year...

My voltage issues were between 3,000 to 4,500 RPM intermittently.
Also when I had my lights on at a traffic light, my lights and fans would dim.

Long story short, I did not have reliable voltage with PA alternators; I tried the 130amp and 200amp version. None worked reliably.

I ended up getting a Performance Distributors alternator due to my unique setup with a ROUSH blower. My voltages have been perfect and strong since then.

I would either go with a Performance Distributors alternator or get one of gmitch's...
Those are the only two alternator sources I would trust right now.

Stock one is too weak for a modded engine with lots of accessories.

 

[eighty6gt]

Stock one is too weak!?

 

[AutoXRacer]

Stock one is too weak!?

If you have extra fans, upgraded fuel pumps, voltage boosters, supercharger coolant pumps, HID lights, stereo, etc. (anything electrical) the stock alternator shows signs of weakness (not its fault, it was not designed to handle too much more than stock accessories).

But for the stock or mildly modded Mustang its great and extremely reliable.

 

[BlueDevil]

Replace the battery and alternator with new Ford parts.

I may get an alternator from the parts store to see what happens. Who buys a battery from Ford?!?!

Check your SJB, could be wet there.

Good call. I'll check that and clean out the cowl area...may be clogged with leaves.

Recheck all your connections to the batt and alt, also sounds like you should get a new batt anyways. Mind as well do that to reduce that as a possible cause.

All connections at battery and alt have been checked repeatedly. I am thinking of getting a new battery, but I don't just want to throw money at the problem. Considering a Yellow Top or equivalent.

I had a similar issue when I first tried a PA alternator last year...

My voltage issues were between 3,000 to 4,500 RPM intermittently.
Also when I had my lights on at a traffic light, my lights and fans would dim.

Long story short, I did not have reliable voltage with PA alternators; I tried the 130amp and 200amp version. None worked reliably.

I ended up getting a Performance Distributors alternator due to my unique setup with a ROUSH blower. My voltages have been perfect and strong since then.

I would either go with a Performance Distributors alternator or get one of gmitch's...
Those are the only two alternator sources I would trust right now.

Stock one is too weak for a modded engine with lots of accessories.

I do have extra accessories (BAP, Afco dual fan h/e, i/c pump, Shaker 1000 stereo (that rarely gets used...haha), hence the 200a alt. The guy at PA aid he'd never heard of a problem like mine, which sounds fishy to me. I have to send my alt to them, have them test it, and have it sent back...all at my expense, unless it is faulty. Then, they will send a new one. I think I'll get a stock one to use while PA does their thing with mine. It's my DD, so it's kind of a pain. I hate electrical gremlins.

Any other thoughts? Advice on battery choice? I understand that the voltage is regulated by the PCM...should I be looking at that?

 

[AutoXRacer]

I got the same reply from PA... I went through two alternators with them with multiple back and forth shipments.

Every time I when back to my stock alternator, everything worked fine.

PA alternators are not a good choice...at least not lately.
I hear they are cheap Chinese rebuilds.

Anyway, I replaced mine with a made in the USA unit for Performance Distributors and my voltage and amperage is rock solid across all RPM ranges and electrical loads.

I would cut my losses now and find another brand.

 

[eighty6gt]

Who buys a battery from Ford?!?!

People who haven't got time to deal with the issues you're experiencing. @ $30-$60/hr you burn up any savings on a cheap battery very quickly.

 

[BlueDevil]

I got the same reply from PA... I went through two alternators with them with multiple back and forth shipments.

Every time I when back to my stock alternator, everything worked fine.

PA alternators are not a good choice...at least not lately.
I hear they are cheap Chinese rebuilds.

Anyway, I replaced mine with a made in the USA unit for Performance Distributors and my voltage and amperage is rock solid across all RPM ranges and electrical loads.

I would cut my losses now and find another brand.

Well damn. That may be what I'll have to do.

People who haven't got time to deal with the issues you're experiencing. @ $30-$60/hr you burn up any savings on a cheap battery very quickly.

True enough.

 

[BlueDevil]

Final update. PA gave me a full refund after 2 of their alts were all over the map on the voltage. Got a Perf Dist alternator (130A I think) and everything is fine voltage-wise. PA never did find an issue with the 2 alts I returned. Strange.

 

[Department Of Boost]

Buy a 167A Denso (135A Denso's started coming on the Mustangs in 2010) from me for $325 w/ no core charge and you will never have an issue again.

And run 2ga to the alternator.

The 6G alternator design (the stock one) is a flawed design. No matter who makes it/re-builds it/hot rods it they have problems, lots of problems. They're junk.

 

[dysan]

There is also the 200amp Mitsubishi alternator that is in the police interceptor crown vic's that can be used as well.

I believe it is this one that will work in our cars...

http://www.autozone.com/external-en...ers-v-4-6l-flex-fuel-sohc/630662_188556_4786/

 

[Department Of Boost]

There is also the 200amp Mitsubishi alternator that is in the police interceptor crown vic's that can be used as well.

I believe it is this one that will work in our cars...

http://www.autozone.com/external-en...ers-v-4-6l-flex-fuel-sohc/630662_188556_4786/

I tried that one in a few applications. If the car is NA it will fit. It would not fit with a Kenne Bell, Whipple or TVS though.

I never checked the connector though. In some cases a custom connector is needed.

 

[dysan]

Ahh...

It should fit my car though with the reverse mounted alternator on the E-force. When I need one again I'm going to try it out.

 

[AutoXRacer]

Final update. PA gave me a full refund after 2 of their alts were all over the map on the voltage. Got a Perf Dist alternator (130A I think) and everything is fine voltage-wise. PA never did find an issue with the 2 alts I returned. Strange.

Same thing happened to me with PA... Their alternators failed in my car, but they couldn't find anything wrong with it. sigh

PA = fail...

 

[Department Of Boost]

Ahh...

It should fit my car though with the reverse mounted alternator on the E-force. When I need one again I'm going to try it out.

It may work, it's all a matter of space. That alternator is pretty big and the power lug/post sticks way out at a different angle and tries to get into all sorts of stuff.

I can get that alternator for less money so let me know if you need one.

 

[s8v4o]

There is also the 200amp Mitsubishi alternator that is in the police interceptor crown vic's that can be used as well.

I believe it is this one that will work in our cars...

http://www.autozone.com/external-en...ers-v-4-6l-flex-fuel-sohc/630662_188556_4786/

I tried that one in a few applications. If the car is NA it will fit. It would not fit with a Kenne Bell, Whipple or TVS though.

I never checked the connector though. In some cases a custom connector is needed.

Ahh...

It should fit my car though with the reverse mounted alternator on the E-force. When I need one again I'm going to try it out.

I'm using the 215 amp crown vic unit. I did have to remove the big plastic power lead adapter that the power wire attaches to because even after modifying it to be clockable it still wasn't working for me. I just ditched the adapter and attached the power wire straight to the stud on the back of the alternator using a thick plastic washer so the power wire wouldn't ground out on the alternator case. So far it's been working great!

Dysan, you shouldn't have an issue with it. I was because the power adapter was wanting to hit the manifold

 

[dysan]

It may work, it's all a matter of space. That alternator is pretty big and the power lug/post sticks way out at a different angle and tries to get into all sorts of stuff.

I can get that alternator for less money so let me know if you need one.

Thanks, I appreciate it.

I'm using the 215 amp crown vic unit. I did have to remove the big plastic power lead adapter that the power wire attaches to because even after modifying it to be clockable it still wasn't working for me. I just ditched the adapter and attached the power wire straight to the stud on the back of the alternator using a thick plastic washer so the power wire wouldn't ground out on the alternator case. So far it's been working great!

Dysan, you shouldn't have an issue with it. I was because the power adapter was wanting to hit the manifold

Good to know. It would be nice to have a 200amp alternator in my car with all the crap I run.