Alternator choices?

[JeepNoob]

So, with the summer heating up and pretty much all of us running the A/C in our rigs, I've noticed my voltage gauge hasn't exactly been sitting where I want it to. With the radio on (I'm not blaring it. Just a good level you could still have a conversation over), the A/C on (Switch in max, full cold, not sure what the difference between max and normal is. My guess is re-circulation?) and the blower motor on pretty much any of the higher speeds (M1, M2, High), my voltage gauge is almost sitting in the red zone at idle. Yikes! Doesn't really seem to change going down the road either. With just the radio on, it'll sit just a tick below the middle of the gauge. Well, I know gauges can lie, so today I did some testing with my voltmeter (not the best way to do it, I know. I don't have access to a charging system tester at the moment.) My battery's the top of line one from NAPA, their premium gold or whatever it is, blower motor and electric fan have been recently replaced, as has the radio, and I've got 4-gauge battery cables. The battery at rest was reading about 12.8 volts (a quick flash with the headlights knocked the charge off the plates and it went to 12.6 or so volts, slowing climbing), but with the engine running at idle, I was only getting about 13.5 volts no matter what accessories I turned on, the gauge kept doing the same thing it does. I know, not a super-accurate test, but I'd like to see that voltage figure at about 14.4 volts. I was looking at parts store alternators, and 90 amps seems to be about the standard rating. That honestly seems way too low to me and with me suspecting my alternator might be getting long in the tooth, I thought about upgrading. My question is, do you guys have any advice on factory replacement alternators? I really don't see the point in dropping $400 or $500 on a high-output, 175-amp alternator, but is there something that might give me a bit more oomph for say, $200 or so? I noticed that 4WheelParts sells 150-amp alternators for a '93-'98 ZJ with a 4.0. Would something like that fit my '96 XJ 4.0? Anything else I should check as being faulty before I throw an alternator at it?

 

[xjtrailrider]

I'm gong through this same issue. My amp draw is more than my 100amp alternator can handle and it cost me $100. I looked at Mean Green but cant justify $400 for 40 more amps.

 

[downs807]

Do a search on here for V8 ZJ/ Durango alternator upgrade. You will need to modify the bracket some and some other things but it's a good upgrade from stock.

 

[cruiser54]

How about verifying the readings using a $5 Harbor freight meter?

 

[md21722]

My 2001 XJ generally shows one tick below 14 and has done this for the past 11 years that I've owned it. Fans, stereo, A/C, headlights, cold weather or desert don't really change it. Only time gauge has deviated was when it was pegged to the right or reading around 10 volts. If the battery is shorted or the cables loose it can read high. Worn brushes have caused it to read low for me You might want to make sure your battery connections are tight and your alternator is performing. The stock one has worked for me. My 1997 reads 14 on the gauge.

 

[ehall]

First, higher output means more windings with larger shells, so physical fitment is typically an issue and requires some clearance work to fit a larger alternator into the stock location.

Also, pre-91 Jeeps used GM alternators, 91-98 used Denso, 99-up used Denso with a different connector. Upgrade options are different for each generation.

On my 91, I am using a brand new 136-amp unit that was stock on some other Jeep/Dodge vehicles. Even with that I struggle sometimes--between the blower motor, the condenser fan, and the second electric fan that replaced the stock mechanical fan, there's a lot of draw. It stays above 12 but just barely

 

[bluejunior]

On my '01 I used a 160 amp alternator from a 5.9L '03 Durango. Works great, same connector as stock so no wiring trouble and the modifications needed to bolt it up were identical to the ZJ swap I'd done before. The only thing special about the durango alt is you need to swap your stock XJ pulley onto it for full benefit at low speeds (the durango pulley has one more channel and is larger diameter, i.e. lower rpm within the alt).

Edit: It HAS to be the 5.9 to get the 160amp. Otherwise it uses the same 136 as the ZJ's. I also did a big three wiring upgrade at the same time, to account for the additional current and try to minimize voltage drop.

 

[Digger87xj]

Older XJ dash gauges are notorious for under reporting correct voltages with accessory loads on. This is due to the way the dash is wired and while there is no downside to an upgraded alternator, just know it will not change the readings on the dash.

Also know, you likely won't ever see 14.5v out of your jeep. This is due to the PCM being the voltage regulator.

 

[JeepNoob]

Thanks for the thoughts and info guys. I used my $20 Crapsman DVOM to get my readings. Not exactly a Fluke, but not Harbor Freight quality either. My 4-gauge battery cables are snug as a bug, battery is properly held down, not sure what the alternator wires look like, but it wouldn't be a bad idea to check the resistance and connectors on them. I'll have to check to see how many wires I have off the back of my alternator. I know Ford uses a quasi-PCM controlled alternator set-up. In this case, the alternator still has an "I"/sense wire and an internal voltage regulator, but the PCM can make fine tuning adjustments to the alternator. I'd really rather not have to make any modifications to the bracketry and such to make a new alternator work. I think I did answer one of my questions though... while searching and comparing part numbers, it seems that any alternator that will fit a ZJ will fit a similar year XJ as well, with the exception of this thing-

http://www.4wheelparts.com/Electric...x?t_c=72&t_s=413&t_pt=3340&t_pn=CRO56041394AA

Judging by the looks of it, it SHOULD fit an XJ without modification. It's also a live-able price and a healthy bump in amperage over a stock 90-amp unit.

 

[ehall]

I wouldn't buy anything like that from Crown, they are alright for small things but nothing that will leave you stranded

What year is your jeep?

 

[JeepNoob]

'96 XJ Sport. I figure worst case scenario, I just bite the core charge (if I even do that seeing as how I'm ordering it online) and keep my old one as a spare in the back. I'm normally rolling around with a metric butt-ton of hoses, rags, piddly parts and tools in the back because automotive program student. I figure what's an alternator on top of all that junk? I've heard of some automotive electrical rebuild shops that will re-wind your factory alternator for more output. It just kinda comes down to finding a good one it seems...

 

[ehall]

96 uses the old-style connector. The largest you can get is the 136-amp that was used in the ZJ and some Dodge trucks/suv.

Get on car-part.com and start looking. http://www.alltruckparts.net/ shows a few of the Durango 136a for $50, and one 98 ZJ 5.9L for unlisted price

You'll need to trim your brackets a little to make it work

 

[Johnnie Walker]

If you have a good local electrical shop that does alternators, go pick up a spare and have them increase the output as high as they can/what you can afford. From what I have seen this price typically breaks down to about 1$/amp.

 

[JeepNoob]

@ehall- Okay, thanks for that bit of info. The link I posted is for a 150-amp alternator that fits a '93 to '98 ZJ with a 4.0. Worst case scenario, I'm pretty good at electrical work and could probably just solder in a pigtail for the alternator. Edit: Oh yeah, I've been to All Truck a time or two. Their selection as far as Jeep parts goes kinda sucks. When my clutch pedal bent, I had to go to another yard to get one. These guys in 'Springs are a bit better- http://www.fnjeep.co/

@Johnnie Walker- Seems about right, I used to have to have somebody rebuild the GEN 2 for old CUCV ALL. THE. DAMN. TIME. (Long story, don't ask. Got to the point where I started to think about doing it myself.) $60 seemed to be the going rate. It was hit-and-miss with rebuild shops, but the greasy, grimey guys who had been doing it since they were like 12 usually did a good job lol. I figure $60 on a 90-amp-ish alternator still nets me 150 amps.

 

[xjtrailrider]

My 90 blew the voltage reg on a reman alternator that I just put in Sunday morning. I ordered a "new" 100amp from oriellys today and got it for the same price as the reman unit.

Like the OP, I know my wiring is good, I checked my voltage, 7.5 volts with a full load and dropping. The battery load tests good, the alternator tested bad

 

[go1lum]

The connections can easily be swapped around. I had to do this to put an older style on my 2000. Had to use all the brackets off the older model too tho. But it was just a few screws and the connections can be changed.

 

[Digger87xj]

My 90 blew the voltage reg on a reman alternator that I just put in Sunday morning. I ordered a "new" 100amp from oriellys today and got it for the same price as the reman unit.

Like the OP, I know my wiring is good, I checked my voltage, 7.5 volts with a full load and dropping. The battery load tests good, the alternator tested bad

91 and up (HO) uses an external regulator....(internal to the PCM.)

 

[Muddzz]

Has anyone tried connecting a non PCM (EVR) voltage regulator to a newer Denso?

I was thinking of installing a second (higher output) Denso alternator to the Jeep.

After temporarily connecting a Transpo C8313 to a 90 amp Denso voltage output stayed above 16 volts max. ~18 volts. Reconnecting the PCM (EVR) voltage output is normal around 14 volts.

The PCM (EVR) controls the alternators field by grounding many times per second one of the field terminals. Where the number of times grounded (in kHz) modifies field terminal voltage. The C8313 (older type voltage regulator) from what I know, instead uses a variable voltage (pos+/neg-) going to the field terminals.

 

[ryurabbit]

I have a 160 AMP alternator on my 92 XJ. Love it but it fried the regulator in my pcm. So now I have an external voltage reg and it works great. Only downside is now the check engine light comes on from time to time because of the alternator circuit on the pcm.

Got the reg from here:
http://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

:bunny:

My alternator is from a grand caravan not sure what year. Bolts in no mods!!!!

 

[Muddzz]

I have a 160 AMP alternator on my 92 XJ. Love it but it fried the regulator in my pcm. So now I have an external voltage reg and it works great. Only downside is now the check engine light comes on from time to time because of the alternator circuit on the pcm.

Got the reg from here:
http://alternatorparts.com/external-voltage-regulator-high-output-alternator-kit.html

:bunny:

My alternator is from a grand caravan not sure what year. Bolts in no mods!!!!

I temporarily connected that kit to a Delco (Denso) 90 amp oe replacement alternator, (98 XJ) adjusted to the lowest voltage setting, voltage output is around ~17 volts, measured directly from the alternator's output.

With the PCM (EVR) connected alternator output is normal ~14 volts. I'm wondering if the voltage reg. CP3818 that came with the kit is faulty or some sort of incompatibility?

Everything was wired as in the instructions, along with a ground wire, except the battery was used instead of the ign. as 12 volt power for the CP3818.

I have another large case Denso alternator that's suppose to have been upgraded to 200 amps. Though I don't know which parts of the alternator were actually upgraded. A good High Output alternator will use six phases vs an OE three phase, plus upgrade the stator, rotor, rectifier and diodes. To have better output at lower rpms. A good high output 200+ amp, should be putting out at least ~100 amps around idle rpms and designed for better cooling.