Lyferxb9s

Can anyone tell me what wire from the alt is the sensing wire? the one that the PCM tells the alternator how much voltage to put out?

scoobyxj

Neither. The PCM does it internally. What are you trying it diagnose?

Lyferxb9s

On the sensing wire of most alternators if you wire in a Diode it will trick the PCM into upping the voltage. right now my jeep charges at 13.8v and I want to increase that to 14.9-15.2

http://www.stevemeadedesigns.com/boa...oltage/page-10

EvstaG

Perhaps more importantly, why do you want to step-up your alternator voltage in the first place?

Lyferxb9s

To completely top off my batteries. Increase the voltage to my accessories and brighten my lights.

jeepmojo

That's done more by amps than volts so you would be better off to get an HO alternator or an smaller pulley for your stock alt.

Lyferxb9s

Not trying to increase amperage, just trying to raise voltage. Can anyone tell me what wire is the Sensing wire?

wrapstar

Both one is positive one is negative. Volts are battery related if you want more voltage you need the alt. to but out more amps to increase the charge. I wouldn't recommend trying to trick the pcm

Lyferxb9s

Both one is positive one is negative? It's a two wire plug. Tricking the PCM with a diode is harmless if done properly. Does anyone know what wire on the plug is the Sensing/excite wire?

wrapstar

Theres two one positive one negative. Iv been rebuilding alternators and starters since I was 14 my dad owns a rebuild company

Lyferxb9s

My alt plug has two wires. Can you tell me what wire is the sensing wire or not?

jeepmojo

I understand that but making your lights brighter, accessories work better etc... Is an amperage issue. If you over volt things they will burn out faster. If you upgrade your alternator to a higher amperage than all your items that draw on the system will get the current (amperage) they need and not be starved...

Lyferxb9s

I have more than enough amperage but my PCM is still telling my alt to charge in the 13s and I need it slightly higher. I found the information I was looking for elsewhere though.

JJCIII

Lower voltage means more amperage, which puts more strain than necessary. You can fix this by upping the voltage. Upping the voltage plus a big 3 upgrade to counter voltage drop on load is much more efficient than just getting a bigger alt. I have a 220a in my 4.0. Putting out 13.6 on a warm day. Also a very important thing to remember is that with a high output alt, the more it can put out then the harder it is for the belt to turn the alt pulley. I'm trying to get atleast 14.4 out of mine. It is also possible to fool the battery temp sensor with resistors to up the voltage. Plus upping voltage isn't going to burn anything out as long as you don't go crazy. Honestly 14.8 is the most I would feel safe running. I'm at the minimum charge rate for my yellow top and I don't like it. And when it comes to car audio guys like me, higher voltage it far more important than just amperage. Mainly for saving amplifiers and wiring when the load drops the voltage and also helps with audio clarity. All amps are rated at 14.4v so running 13.6 means considerably less out put and less clarity.

wrapstar

Can you explain how its harder on the belt.