Low Voltage. AEM culprit?

[SquadX]

Car is a paxton GTS 2000 with AEM and fuel system.
Issue: While out driving this past Friday and making two stops at stores i noticed voltage was at 12 after the second stop. Drove car home but on the way the volts drop to the yellow and then between the yellow and red line. Car never died though. Once at home I turned on the a/c to see if it would die ut didnt. Shut car off and tried to turn it back on but wouldnt becuase of voltage. Came back four hrs later and car started right up but voltage was only slightly pass 12. Started car up today and it starts right up again and volts climb to 14.

Car has on occassions went to low 12s but never pass it and i never turn the a/c on because of this.

Battery is two months old and alternator is original. I am thinking its the AEM. Anyone run into this issue? Called AEM and they said to ship it to them but didnt have any inslight on a possible issue besides replacing parts.

 

[SquadX]

From my understanding the AEM acts as a voltage regulator.

 

[Russ M]

Its possible I guess, but my first thought would be the alternator. Did you charge the battery in between the time you say it started showing 14 volts?

 

[SquadX]

Nope, didnt touch car besides starting it up. No battery tender.

 

[VIPER BAZ UK]

DC Performance know these inside out..........

 

[SquadX]

I plan to call Dan but wanted to test m alternator first.
Will a volt meter give me an accurate measure of the alternator as Id hate to have to pull it with the paxton on there and get it bench tested.

 

[V10TT]

The voltage regulator is inside the AEM.

 

[SquadX]

Im hoping its the alternator over the aem.

 

[Russ M]

Don't be afraid of AEM tech support, they are all very good at what they do and if it is a problem with the unit they will find it no problem.

 

[SquadX]

I tested the alternator with a voltage meter yesterday and this morning.
Yesterday right after start up at idle voltage was 13.3, with A/C on it jumped to 13.4-5 with A/C off. Went for a spin, getting on it some and afterwards reading was 13.4. Test and drive were done mid day lunch time.

This morning after start up at idel reading was 14.5 with A/C off. Test done morning 8 am ish.

Something else I noticed yesterday while driving...when I pressed the clutch in, the rpms would dip slightly below 500 but bounce right back to my normal idle rpms of 600 (does not happen all the time). In there cars Ive have that this rpm dip has happen in it has always been the alternator. Next is to test the battery which blows to get to as many know.

 

[Russ M]

The rpm issue can easily be just a tuning problem.

 

[Russ M]

The rpm issue can easily be just a tuning problem.

 

[SquadX]

I just had it tuned so I hope not and it was not present after the tune. tuned early June of this year.

 

[SquadX]

Well I had the alternator rebuilt. New battery and aem repaired by aem and it still has the same problem. Took it out last night and after 20 mins the volts dropped from 13 to mid 12 and held there for 15 mins then started to drop until it got down pass 12.
After I put the repaired aem in the car wouldn't start because the battery was low so I tried to jump it but that didn't work so I purchased the new battery. Could trying to jump start it have caused an issue.

Below is what aem said was the problem and was fixed:
Issue Resolution:  Inspect: Inspected unit, found burnt pins on two boards.  Will have to repair and replace components in order for unit to be functional again.

 

[SquadX]

Bump.........

 

[SquadX]

Bump.......

 

[99 R/T 10]

I know AEM had ground issues. Is it possible that a "bad ground" on the AEM is causing the pins to burn?

 

[plumcrazy]

mike beat me to it. i have heard of the ground issue a few times

 

[SquadX]

Ok chuck mention the bad ground as well. I'll call then today but this is getting old. Within hrs of reinstall and driving, same issue. I hope they don't try and charge me again to fix the issue.

The isolated charging option is starting to sound vet tempting right now.

 

[SquadX]

Guys thanks as always.

 

[SquadX]

Question. The bad ground wouldn't have anything to do with the volt regulator?

 

[Russ M]

My bet is someone altered the factory wiring for whatever reason and its causing your problems.

Most people think that its no big deal to tap into existing wires for power/ground/etc/etc. Well as you can see it is a big deal, the ECU wires are not to be touched period.

 

[SquadX]

i guess the problem is what do i do. The issue is isolated to volts dropping right now, so im gonna have my viper tech go through all the wires or have a separate charging device installed.

 

[SquadX]

Also would my tech be able to find a problem if the wiring if it exist?

 

[treesnake]

Also would my tech be able to find a problem if the wiring if it exist?

Did you splice your AEM wiring to the sensors or did you use a John Reed harness?

Also, I had a problem very similar to this and the problem was the battery. My car's battery would test OK but but would start to act like you are describing.
I changed the battery and never had the problem again.

Good luck. I know how frustrating it is...

 

[SquadX]

Dc perf did the work so I'm sure they did it correct. I never touched any wiring as I have no idea what would fixing.
I purchased and installed a new Bosch battery the day I reinstalled the aem.
I'm gonna have my viper tech gone through the wires for shorts etc and if he doesn't find anything then I'll probably have the external charging device installed.

In the pass I've noticed the voltage drop if I turned the ac on or was operating both windows simultaneously.

 

[Dan Cragin]

You might want to check the connector at the back of the alternator, the positive quick disconnect near the left front wheel housing (could be loose) or the ground from the engine to the right frame rail.

Hope this helps.

Dan