[JaguarShane]

I have a 1988 Jaguar XJSC with the 5.3 V-12. I have done a lot of mods over the Winter which included getting rid of the 60 amp original alternator and adding a 6N 130 amp alternator. The original alternator was a single or dual wire system depending on how you want to look at it. Battery Cable and wire to the light & gauge.. The 6N has three wires plus the battery cable. I wired it as the plug instructed but that has to be wrong. my Optima battery only lasts 4 days of light driving. To complicate matters, using a volt-ohm meter with negative to ground and positive to the battery cable on the alternator I get a negative read. (i.e. -12.6V) The read with the engine running is also bizarre to me, especially with the original alternator wire reading much higher than the battery cable. Can't figure out where I went wrong.

 

[JaguarShane]

Original Wiring diagram

 

[69612]

that is going to take some doing to research how to make that charge.. its a pulsewidth controlled voltage regulator/module on that...

its for a Ford Expedition: 2007 - 2009, Lincoln Navigator: 2007 - 2009

i will have to dig around and try to find out how that ford alternator receives signals.. and what signals they receive..

ps.. if that is your alternator with the blue pulley.. i was snooping thru your photostream sorry... those phillips head bolts/screws.. may not be tight enough to prevent rocking..

i am heading to sleep now.. i will dig into your issue tuesday night or perhaps tues afternoon.. i did find part of the answer with the 2007 navagator charging diagram

but don't give up yet... there may be a way to convert it to a conventional regulator control.. the guts of the alternator are still the guts of the alternator.. its the load sensing done between the B terminal and the A terminal in the PCM... the PCM also knows what is turned on and what is not via the BCM or if they still use something like the GEM module...

i will search this out tomorrow night..

 

[69612]

this may be as easy as unbolting the rear alternator dust cover and removing the 2007 to 2009 voltage regulator brush holder assembly and installing a NON PWM version or perhap.. i would bet that at least one of the voltage regulator companies makes a ONE or 2 wire conversion regulator for it..

heck... might be able to gut the regulator electronic and wire up a stand alone regulator to control the field windings.. again.. i have to look farther..

i see at least 8 6G voltage regulator possibilities in a 2008 dated catalog.. i bet there are more now.. but i need ZZZZ.

 

[69612]

hmm... possibles ??


FORD VOLTAGE REGULATORS, Ford type

these might be right at your local parts store or alternator rebuilder.

there are several on this page with I D A terminals... W/O LRC load R? control

some have 14.0 and others have 14.4 volt set points..

look at the various 6G regulators ..

if you look at my attachment... it shows the wiring pinout at the regulator to alternator..

i don't think the white one i linked an image of is the right one.. but it shows that ford actually still uses the stator signal..

the stator is the AC signal off the bound ends of the stator windings.. it has about half the alternator output voltage when its charging.. but in AC volts..

the voltage regulator uses this stator signal to control the rotor winding pulses.. so that there is no surging while changes in RPM happen..

here is a video on the 6G voltage regulator change. you have a 6N.. hmm... i wonder ...

http://cyberspaceandtime.com/How_to...Alternator_by_alternatorman/JuKCrnoe_Vs.video

 

[JaguarShane]

Yes, that is the alternator, and please, snoop away at the pics and links, that's why I publish them . I put the two brackets on top to help stabilize the alternator. There's also 2 socket head bolts underneath. I wanted 4 contact points to make sure it didn't and couldn't move Conducted extensive reads this evening, all with loads off. 4 pages in my little notebook LOL. I'm starting to think that a large part of my problem may be related to amps. I started with 12.66 volt read at the battery when I was done with all of the phases I ended up with a 12.60V .... an hour later 12.56V. Even at 12.56 The engine took some rolling over to start whereas 12.66 fires up at the touch of the key. With the engine running and the alternator plug un-plugged I checked the B+ lug on the alternator and I got 14.0V. When I put the plug back on the read at the lug was 12.6 and the idle slowed down. Hmmm more confused now than ever.

 

[69612]

print and perform this if you had 14.0 at the output terminal...

and warning.. if the output terminal to the battery connection is crazy... you could have damaged the alternator diodes..

recall the image of the voltage regulator and brush set i linked... if you remove the rear cover.. you should be able to PROBE the Stator terminal with the charging system working.. if you have 14.0 volts of output. you should see very close to 7.0 volts AC on the stator..

if you only have 12.6 volts DC of output.. and you have 7.0 or more volts AC on the stator terminal.. you have bad diodes...

the Stator terminal is connected to the end of the windings.. the other end of each of those EACH goes to the positive and negative diodes..

any voltage above ZERO goes thru the positive diode to the output terminal.. any voltage below ZERO goes thru the negative diode to the alternator frame and into the engine block then up to the negative battery post via the negative cable..

remember.. electrons move from Negative to Positive..

oh.. the ULTIMATE voltage drop test i compiled..

here is a DIRECT LINK to the voltage drop test

http://i.imgur.com/WMDprhm.jpg

here is the test for viewing..

please perform the test step by step.. if you have questions..post them..


please perform the printed voltage drop test on a different car or truck for practice.. so you know what your volt meter is displaying...

try to use a volt meter that costs over 10 bucks.. the really cheap HF and free versions are not accurate at this tiny fractions of a volt that indicate good or bad..

 

[69612]

i just woke up....

realized you have a REAR/Trunk MOUNTED BATTERY.. DOH!

to perform the voltage drop test properly with the rear mounted battery involves creative use of a JUMPER CABLE..

test 1... right at the battery in the trunk..

test 2, 3, 4.. connect a single jumper cable clamp to the Negative terminal of the trunk mounted battery. clip the front end of that jumper cable to one of your test leads. then you can perform the ground side tests..

test 5 and 6... with the single jumper cable laying safely on the floor next to the car... the meter can still be clipped to the front clamp... move the rear clamp over to the positive side and perform tests 5 and 6..

if you have a terminal block in the front where the starter cable attaches from the battery... you can use a ford starter cable.. usually goes from the starter solenoid to the starter .. called switch to starter cables.. they are premade in 16", 18", 24". 32", 40", 49" lengths for up to 3/8 terminal..

with a 130 or 150 amp alternator.. you will want at least a 4 gauge.. they make them in 2 gauge also.. you should be able to create your own length...

if you have no battery terminal block with a thick cable running back to the battery from the engine compartment..

can you fish the new cable.. leaving the existing wire in place down the back or over the side of the alternator.. down past the motor mount to attach to the starter top post directly.. so you will be still using the thick cable to the trunk mounted battery..

i hope this helps..

i did a similar thing to the countach.. there was a major voltage drop between the rear of the car and the front and then back to the rear of the car.. i ran a 4 gauge cable on top of the existing wire over to a terminal block beside the motor i installed out of sight.. this terminal block i moved the various engine bay relay power connections to...

the wiring to the front of the car also was connected there..

but the pair of radiator cooling fans, the ac compressor clutch, the fuel pump relays and the fuel injection relays were all powered directly off the alternator.. its a 135 amp alternator.. and a 8 gauge cable running to the front mounted battery was just too far. i know purists will hate me.. but when i got the AC and separate defroster/vent blowers working up front. the owner said they had never worked that good and actually cooled the passenger compartment.

getting rid of voltage drop is why i compiled that test..