ok guys, i am in alternator/charging hell!

G

Gunter

NAXJA Forum User
Location
Aurora, Colorado
again....it is dead and no chargy. wtf??
so i have continuity with all my grounds, IE they all work. checked with Ohm meter.
i have all the usual functions , IE all the lights and all the horn etc are working.as i cleaned up the grounds,all the non working lights etc came back and work as intended.
the alternator when it was working, made 14.25 V and 6.5 A on the fluke multimeter.
the battery takes a charge when the alt works.
both are new.2 weeks old.
now today the alt wont charge--

i HAD a semi cut and corroded wire on the plug to the alternator. i got one from the junk yard and wired and heat shrunk those repairs, soo all is sealed.
either i have one of my repaired wires ****ing me up--
or a bad alt right off the shelf.
the alt plug, the wires are one to excite the field,and i guess the other is for the dash light? and when the alt was working, the dash light was working fine and still does. as the engine starts, the light goes off. if the alt stops charging,shouldnt the light come on?
monday i had a wierd screaming noise from the truck...maybe a stuck alt brush?

i am going to tap the alt and see if the brush is stuck and if it releases.
then check the plug to see if it has voltage on both wires.
if i cant get it to charge i am taking the new alt off and i had the old one tested so i know it works now..
then see what my numbers are. damn i hate this !!
 
Why not just replace the wire in its entirety than hoping for a good repair? Would be a good start to eliminate any loose ends :D
 
update--
voltage on the 2 wires in the alt plug.
all battery wires and cables in good shape, no corrosion
all the ends are good.
battery will charge on a wall charger, but not in vehicle.
put original alt back in and tested the new one. both alts test out fine.
either one has same symptom in vehicle, wont charge battery.


so cables good,grounds good,alt good,battery good,voltage to alt to excite the field,and voltage to the other wire as well.
my alt has 2 wires in a factory 4 wire plug. both wires show battery voltage.
the cable on the back of the alt is original and in good shape, no corrosion etc wire in good shape.
 
Last edited:
You drive a RENIX. Pull the battery cable while its running and see what happens!

One vote for another new alternator.

EDIT: Did you load test the battery?
 
Have they been tested at different shops?
 
ok "simplified " some crap that was in my way....and fixed a few more wires.found two old repairs and re did one of them. sent battery out to be recharged. and read a lot of my situation and i still need to do the dash cluster re ground. re did and re cleaned and re sanded the dipstick ground point.and all those ground wires too,and added dielectric grease to protect the grounds.
possible further steps--
ground the alt with a wire and ends.
get an external regulator


and my old battery and new one do the same...just like old and new alt.still same malfunction. i ll be back in a bit--
 
from 5-90 post on jeeps unlimited--

"1) RENIX used a Delco CS-130 alternator, which is internally regulated.

2) RENIX alternators are grounded through the mount, the engine block, and the main ground lead about 2/3 back (it's attached above and behind the distributor, passenger side.) Valve cover seepage often gets into this connection.

3) The RENIX IP voltmeter is a notorious liar. As mentioned, verify that suspect reading with an independent DMM, connect it to the battery.

Delco alternators are actually pretty robust, I've used them on Gawd knows how many conversions (SI and CS series) and in myriad industrial setups. I prefer them over just about anything else.

However, Point #2 should be particularly noted. If you think you're having ground trouble (a typical cause for "floating voltage at steady-state operation,) I would suggest making a test lead out of 10AWG or maybe 8AWG wire - make it long enough to go from the alternator case to the battery - post. You may use clips on both ends, or you can put a 5/16" or 3/8" ring on one end - there is a boss on the back of the alternator case, drilled & tapped M8-1.25 (use a 20m/m long screw. Using an overlong screw there can bind the rotor - it's a through hole, usually.)

If this additional ground settles down your voltage readings, then clean your main ground (since it's also the primary ground for engine management sensors,) and consider making the alternator ground a permanent installation (rings on both ends - a 5/16" or 3/8" will also fit to the battery clamp bolt and most binding posts.) The alternator direct ground may also be run to the stud where the primary ground attaches - but why not just go directly to the battery? Use min. 10AWG wire for a permanent ground (although 6AWG - same as OEM mains - would be preferred. However, you're augmenting an existing ground, not creating one from whole cloth.)
"

i have followed this and as i said, found and checked/repaired other damage and less robust repairs. i ll post up how it goes in a little while,still need to get under the dash.

G
 
You should have what is known as a GM CS130 alternator. Lets go over the connections.

First off, As a test, by-pass the factory battery charging wire and use a length of 10 ga wire from the "BATT" post direct to the battery positive. Don't care how you connect it at this point as it's only a test.

Start it up and See if it's charging. DO NOT TRUST THE DASH GAUGE. Use a multimeter at the battery... should be getting ~14.5V

IF it is charging as it should, permanently disconnect the factory charge wire by clipping each end, and install your new wire permenently. You might even double it up by running a couple parallel 10 ga wires, or opting for a larger gauge wire altogether. I've found that 2 work just as well as 1 larger one and less money to boot.

IF it is not charging, time to dig in a little more.

Funny thing, AllData doesn't show charging diagrams for the 89... so we'll wing it until they get back to me

Different manufacturers use different wiring techniques for the same alternator, so the 89 XJ may use some combination of the following.

CS series wiring pin-out:

  • S = When used; Heavier gauge wire to battery positive (Sometimes a loop back to the BATT post on back of alternator.).
  • F = When used; connected to Ignition 1, 12v switched, hot in run and start. F terminal has internal resistance to energize the alternator.
  • L = When used; Small gauge wire that can come from the idiot light. This terminal requires a switched, resisted 12v supply. Resistance of 35 to 350 ohms is required. In the case of the idiot light, the bulb serves as the resistance. With a gauge a resisted wire is used, connected to Ignition 1, 12v switched, hot in run and start.
  • P = Haven't found a instance of use.


If it were mine I would buy a new pigtail and connect BATT, F and L. This is a no-nonsense hook-up and works flawlessly for the hot-rod crowd.



Until I get a wire diagram, if you could do me a favor and look at yours, and report back which pins have wires.


I then can tell you how to test them in detail.
 
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yeah did everything but the dash ground. no change.
i had a wire from the alt to the pos on the battery did not make any difference.
the plug on the alt has 4 positions,and the 2 middle ones have the yellow wire and the brown/blue?.the pins are 3 small ones and one large one,the yellow is right next to the large one.
since all this mucking about i lost the idiot lights on the dash.
both plug wires have battery voltage. the yellow is the wire to energize the field? and the other is idiot light?
so how to bypass the truck wiring so the battery will run what it needs to and the charging is separate?

tell you what, i ll go disconnect the oem alt wire and connect the wire directly from batt pos to alt. then check my readings. brb
 
ok question here:
do the jeeps have a resistor in the alt light to keep the circuit excited in the event the light burns out? when i lose the ground on the idiot lights, is this the same result (for the alt) as the bulb failing? IE losing the signal to excite the field?
and if my idiot lights are all out(water temp,oil pressure and voltage) will this be the same as the light bulb failing and losing the signal to excite the field? which will make my alternator stop charging.
my thing right now that is not coming back, is the idiot lights. which should be a fix of the dash ground. i *think* i have the rest worked out.
 
renix alternator not charging and bad grounding issues.

damn !
i found a thread on Pirate 4x4 about alternators.
http://www.pirate4x4.com/tech/billavista/Wiring/Part2/#wiring
this SHOULD be enough to fix anything.
i THINK i am at the point of fixing/checking everything that COULD be the cause,and all i have left is the idiot lights went out again. fixing that should bring my charging system back up. i think it is currently not charging because of the MJ/renix ground issues , and then losing the signal to excite the alt field in my alternator.
as far as i can tell, everything else has been fixed or checked and repaired as needed.
some alt systems have a 50 ohm resistor built inline in case the bulb fails so you wont lose your field exciting signal.
i think MJ's dont, but in the near future mine will. easy upgrade for reliability sake.

G
 
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