Alternator swap question

J

jimmy21669

NAXJA Forum User

Location

Hagerstown, MD

• Jul 8, 2010

• #1

I recently acquired a 157 amp Denso out of a Ram 3500 van with a wheelchair lift. Super high capacity.

I am going to swap it in and upgrade to 4 gauge with a 175 block fuse.

Here is the question: I have a 91 and the OEM alt has the two terminals for gauge and ignition. The one I acquired has the pigtail. How do I know which is which for splicing the two together to make them work?

Thanks

 

D

dave92cherokee

NAXJA Forum User

Location

Lynchburg, TN

• Jul 8, 2010

• #2

From the sounds of it you have the older style internally regulated GM style alternator in your xj and the one you got sounds like the later model PCM regulated style. If that is the case then there's no way to make it work as the voltage in one is controlled by the alt itself and the other is controlled by the computer.

 

J

jimmy21669

NAXJA Forum User

Location

Hagerstown, MD

• Jul 8, 2010

• #3

I have a 91. They are both externally regulated. I have checked. I had them both tested on the machine at Vato Zone... Both are Denso alternators. Mine is just a 90 Amp with the post rather than plug terminals.

 

J

jimmy21669

NAXJA Forum User

Location

Hagerstown, MD

• Jul 9, 2010

• #4

Anyone?

 

D

dave92cherokee

NAXJA Forum User

Location

Lynchburg, TN

• Jul 9, 2010

• #5

If that's all it is is going from the stud attached block to the plug in style like the 97+ have then just cut one of the plug in connectors from an xj in a jy then cut the block off and splice the two together. That's what I did on my 92 when I switched to the 160A alt.

 

J

jimmy21669

NAXJA Forum User

Location

Hagerstown, MD

• Jul 9, 2010

• #6

IS the splicing self explanatory? I have a 50/50 chance of getting it wrong...lol

 

D

dave92cherokee

NAXJA Forum User

Location

Lynchburg, TN

• Jul 10, 2010

• #7

The wiring doesn't matter as all it does is run across a coil inside the alternator. The varying input voltage from the ECM controls the output current of the alt. I recommend soldering the wires but they're extremely resistant to heat so it takes a little while for them to take the solder.

 

J

jimmy21669

NAXJA Forum User

Location

Hagerstown, MD

• Jul 10, 2010

• #8

I got it done today....I figured the BIG black wire was a case ground, so I grounded it to the case...then I splice the other two together. Everything works fine, 14.5 volts at idle.

Unfortunately, now my starter is shot...lol