Charging issue ?

[candymancan]

The alternator on my 90 is pretty much brand new, the previous owner had it installed and the wiring job on it looks pretty good. However i think the alternator is too small, ill have to check the thing again but i think its only 60-70 amps last i checked... When i start the Jeep up voltage on the dash is normal 14v at least and all the headlights and stuff are bright. However once it warms up and i tap it out of high idle and put it in gear with the heater blower on high and the headlights/fogs on the voltage is very low and everything is dim. I can tap the gas pedal to raise rpms and the lights gets brighter.. the dash reads below the 13v line. Like when i drive 10mph in my neighborhood and come to a stop sign and i hit the brakes.. i can see the headlights and dash flicker dimmer from me pressing the brakes..

I checked the battery with a multimeter and oddly the battery is being charged at 14.2v with everything on. When i turn it all off it reads 14.40v. I checked the dash gauge and it was reading on 13v... Something isnt right..

What should I do ? Its like the battery is getting a good charge but everything on the Jeep isnt getting enough power it seems. Or could the alternator be supplying enough voltage, but its just not enough amps ?

[shimniok]

Three things come to mind...

1) Belts. Eliminating the obvious, are the alternator belts in good condition? Are they adjusted tight?

If glazed or loose, they'll slip and, at idle, the alternator RPM won't be high enough to deliver the required power. The vehicle will exhibit the dimming symptoms you mention. It'll be more obvious with a high demand on the alternator. BTDT.

2) Alternator capacity. The stock alternators for the Jeeps are in the 60A range which I think is large compared to cars. So if you have a 60A you're fine unless something is wrong with it. if the regulator is out it'd probably either not put out 14V ever, or it'd put out ~18V always. BTDT

Do the headlights flicker regularly at idle? If so you have a bad rectifier diode which can be replaced (I have a write up on this on my blog if you want it). The flickering might lessen considerably as rpm increases, which is why I mention this. This happened to me once too.

Another possibility is that a very high capacity (120A+) aftermarket, high zoot, 12SI alternator was installed, one which doesn't deliver enough power at idle. I'm assuming you're running the stock, Delco 12SI form factor. Mine is a 94A which does fine at idle (which is why I didn't go all out).

3) Resistance. If you're certain you were measuring ~14V at the battery terminals with engine idling, despite having the blower and headlights on and witnessing dim headlights, then do this:

Measure voltage in the cab at the same time. If cab voltage is lower than battery terminal voltage, then Ohm's Law* says there must be resistance between the two measuring points. In the form of missing ground strap, fusible link about to give out, corroded wiring harness/firewall connector, or something like that.

However... resistance in wiring and connectors wouldn't change with rpm or current. It wouldn't explain the dim-at-idle symptom. That's why I suggest #1 and #2 above first

HTH and good luck.

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* Ohm's Law: Voltage equals Resistance times Current or V=IR

[Tatsadasayago]

I agree with all shimniok wrote and would add that slipping belts don't always make noise. Being a 90, your GW likely has A/C and the dual groove alternator. Getting both belts to remain tight can be a real hassle--even with a matched set. In my dealership days I would adjust the belts so the tighter of the two deflected about 1/4" rather than the 3/8 to 1/2" the factory recommended.

Yes, a faulty voltage regulator will either disable charging altogether or cause the alternator to Full Field which will melt stuff pretty quickly.
It used to be you could buy diodes, heat sinks, brushes, internal regulators and brush holders at NAPA and do a home-brew reman. With basic hand tools and a multimeter you can do it yourself for cheap and learn a few things in the process.

[serehill]

Alternators Have Brushes??

WA HUH?

[babywag]

You may want to check the ignition switch.
I have seen reduced voltage @ output wiring off ignition switch 14.x going into switch, 13.x coming out.
If it's the 30yr old switch might be time to replace it.
That or you may have a wiring issue somewhere else?

[tgreese]

Alternators Have Brushes??

WA HUH?

They do. Not like a generator, since the slip ring does not have gaps like a commutator. So they don't wear out like generator brushes. But they are in there - that's how the rotor (field) gets power.

[serehill]

Alternators Have Brushes??

WA HUH?

They do. Not like a generator, since the slip ring does not have gaps like a commutator. So they don't wear out like generator brushes. But they are in there - that's how the rotor (field) gets power.

Yeah I know

[shimniok]

It used to be you could buy diodes, heat sinks, brushes, internal regulators and brush holders at NAPA and do a home-brew reman. With basic hand tools and a multimeter you can do it yourself for cheap and learn a few things in the process.

You can still get the parts, if it comes down to needing a rebuild. Just search for Alternator Repair Kit and it will turn up tons of 'em on ebay and amazon and probably every auto parts store. The write up for the rebuild I wrote is here: http://tc.wagoneer.org/2012/08/delco-al ... guide.html

[candymancan]

Well the belts were i guess a little loose. The alternator yes has 2 grooves for 2 belts.. When i got the FSJ in the spring last year my first thing i did was a complete tuneup with all new belts. I have already tightened them once, but i guess they got loose again ? Or stretched more. 1 of them was kinda tight and the other was more loose. The power steering was deff loose, so was the air pump. So they are all tight now. So far today anyway the voltage was holding on the 13v line or a little above and the lights werent dimming.


But basically when the voltage goes low.. The voltage is in the red on the gauge but on the battery it read 14v.. And of course when it was in the red my headlights and dash lights and interior lights were barely on the whole Jeep was low on power even the engine started to slow down like the spark plugs werent getting enough juice, and if i tap on the throttle the power goes up and lights brighten. As far as bad wires.. i have been through 90% of the wiring on this Jeep ive replaced all the bad wires under the drivers seat from the water corroding them and turning them black. I replaced a few melted wires under the Hood which were the fog light wiring which was melted all the way to the firewall, and i replaced and added a inline fuse to the electric plug thingy that keeps the engine hot idle at factory spec. I forgot what its called it has a plunger that pushes out against the throttle lever so you dont have to manually adjust the idle.

The wiring behind the dash all looks good from the pics videos ive taken and from my head getting as far under there as i could get. I dont know the condition of the fuse box or the ignition switch. But are you sure the ignition switch would cause the entire Jeeps light to dim extremely low when the heater,lights are all on. It isnt just the gauge showing low.. its every light on the car dimming. I hit the brake pedal and release and i can see the lights flicker even dimmer.

But so far today anyway the power seems fine with the belts tightened. But they werent that loose tbh.

Also didnt the older "wagoneers" only come with a 63A alternator. But the grand wagoneers had 90-94a alternators ?. Also 60A isnt that high of an amperage alternator someone said it was "high" amp lol. My 98 ZJ has a 150A alternator from factory. When i dropped down to a 136A voltage on the dash when everything was on, lights, blower, heated seats ect.. Voltage would drop to 13v or less sometimes. A simple 14A drop in an alternator did that, and i know other 5.9 owners experience the same issue since the 150A isnt made anymore.

So going from 90 to 60 is a big drop in power. Just saying. I mean im not a electrical expert.. i hate electrical. Where should I start to find out where the voltage loss is coming from using a multimeter ? Also The alternator is 60Amps. Its a brand new alt one of the previous owners installed. And i say one because im the 6th owner and the last 2 owners didnt put more then 4k miles on the car lol. Im going to take pics and put them on this thread tomorrow to show you how it was wired.. But it was a alot of wire cutting and they didnt solder the wires together either they used those butt connectors. When i did all the wiring on my Jeep i soldered and heatshrinked. I hate those butt connectors.

I mean it looks like they did a correct Job wiring it, even replaced the thick red cable and zip tied all the wires away from the exhaust manifold



http://www.southwestspeed.com/?sec=view_part&id=28739. Look midway through this. The Grand wagoneers had 94A alternators STOCK.. I have a 60A on my Jeep 30 amps lower then stock.. I really think this is the issue


1975-1977 GRAND WAGONEER (J SERIES) FULL SIZE, J SERIES PICKUP, ALL V6 (STOCK ALTERNATOR WAS 63 AMP)
1978-1979 GRAND WAGONEER (J SERIES) FULL SIZE, J SERIES PICKUP, ALL (STOCK ALTERNATOR WAS 63 AMP)
1980-1991 GRAND WAGONEER (J SERIES) FULL SIZE, J SERIES PICKUP, ALL (STOCK ALTERNATOR WAS 94 AMP)

[shimniok]

Well the belts were i guess a little loose. The alternator yes has 2 grooves for 2 belts.. When i got the FSJ in the spring last year my first thing i did was a complete tuneup with all new belts. I have already tightened them once, but i guess they got loose again ? Or stretched more. 1 of them was kinda tight and the other was more loose. The power steering was deff loose, so was the air pump. So they are all tight now. So far today anyway the voltage was holding on the 13v line or a little above and the lights werent dimming.

Good! Hopefully that solves it.

But basically when the voltage goes low.. The voltage is in the red on the gauge but on the battery it read 14v.. And of course when it was in the red my headlights and dash lights and interior lights were barely on the whole Jeep was low on power even the engine started to slow down like the spark plugs werent getting enough juice, and if i tap on the throttle the power goes up and lights brighten.

That all sounds familiar. Mine has done that when cold -- because belts were slipping.

Also didnt the older "wagoneers" only come with a 63A alternator. But the grand wagoneers had 90-94a alternators ?.

I had to go look to be sure I wasn't full of it My 1984 Jeep Tech Service Manual (TSM) lists the following alternator options:

42A Standard
56A Optional
78A Optional
85A Optional Fleet

Also 60A isnt that high of an amperage alternator someone said it was "high" amp lol.

Like Einstein would say, it's all relative lol. I'm the "someone", by the way. I wasn't comparing it to today's cars... more thinking about like passenger cars without electric everyting from the 80's. But...ok... maybe I am inaccurate (full of it) on that statement lol

My 98 ZJ has a 150A alternator from factory

I think they put higher amp alternators in cars nowadays maybe due to all the luxury features like heated seats, heated mirrors, moon roofs, higher watt stereos, factory subwoofers, etc.

Back in the day they put ~100A alternators in luxury Caddys with all the bells and whistles. So, ok, 60A isn't particularly high even by standards set back then. Anyhoo...

If the problem occurs, it'd be interesting to see if a 78A alternator (or higher) would solve it. Then the question is, where is all the juice going. Suppose you have 55W halogen headlights (2) and 55W fog lamps (2). Power=Current * Voltage, so current = 55 / 13 = 4.2A, total current is about 17A. If you added up actual current draw for heater blower motor, and whatever else, that should give you your answer. Of course you'd have to find out the actual current draw of each. Or just add up the fuse values (of course they are probably higher by 1.5x or 2.0x or some factor).

So going from 90 to 60 is a big drop in power. Just saying. I mean im not a electrical expert.. i hate electrical. Where should I start to find out where the voltage loss is coming from using a multimeter ?

If the problem comes back, I would start by eliminating voltage loss by making sure that the solenoid + terminal where the battery + hooks up reads the full voltage at the same time the interior & head lights are dim and the interior voltage (read with the same multimeter) is reading lower. If they read the same (both low) then voltage loss is in the alternator (due to excessive current or insufficient capacity or similiar problem).

If they read different, then you could test voltage at the fuse block, ignition switch, and other points to see if a corroded connection or bad switch or bad fusible link is causing voltage loss.

Also The alternator is 60Amps. Its a brand new alt one of the previous owners installed. And i say one because im the 6th owner and the last 2 owners didnt put more then 4k miles on the car lol. Im going to take pics and put them on this thread tomorrow to show you how it was wired.. But it was a alot of wire cutting and they didnt solder the wires together either they used those butt connectors. When i did all the wiring on my Jeep i soldered and heatshrinked. I hate those butt connectors.

Yeah I try to avoid those on important stuff unless I solder and heat shrink them.

http://www.southwestspeed.com/?sec=view_part&id=28739. Look midway through this. The Grand wagoneers had 94A alternators STOCK.. I have a 60A on my Jeep 30 amps lower then stock.. I really think this is the issue

If capacity was the issue, I would expect belt tightening to have little or no effect.

[candymancan]

Well its still was better today but still too low on power when everything is on for my tastes...

I didnt have my multi meter with me tonight when i was driving around but i took pics.

Here are 4 pics of various voltages when stuff is on.

Also you said 17A with the fogs and headlights, you are forgetting the orange markers in the front and sides, and the red markers on the sides, and the tail lights and then the brake lights. Brake lights use a lot of power. You are also forgetting the ignition coil/spark plugs. How many amps does the blower motor use ? 15-20 ? Then the rear defroster and wipers and the radio. I just dont think 63A is enough.

Tomorrow ill try to probe around with the multi meter but im certain its this alternator. I know alternators dont put off max amperage at idle rpms. But its clear the draw when i turn things on one by one is deff lowering the voltage output when each item is on.

First pic is with everyone off in idle.



This pic is with the headlights on, but no fog lights



This 3rd pic is with the fog lights on and brake pedal pushed



4th pic is with the lights, fog, and the blower on high

[shimniok]

Wasn't forgetting, just didn't want to waste the time finding out the current draw of each of those.

Let us know how it goes with the new alternator when you get it in...

[candymancan]

Itll be awhile. But at least the voltage isnt as bad as it was with the loose bekts lol thanks for that.

When thr belt was lose thr voltage was in the red engine didnt wanna run when i put put in gear lol and thr lights were so dim they were dark yellow lol.

I mean the viltages when the blower n stuff are on.. while im driving are fine of course an alternator output is highest when at what 2k rpm or so i heard ?

I mean am i wrong to think going from the stock 94 to 60A is the reason ? Do you have a 60A in yours ? If so What is the voltage reading when everything is on brake depressed in gear idle.

Or maybe someone with a 60A can chime in

[shimniok]

I hope someone with 60A will chime in.

I don't remember with any precision how the smaller alts behaved. But I would agree something is amiss given the pics you posted. That seems like a lot of voltage drop for just basic accessories being on!

I think it's worth installing a 94A or higher whether it helps that particular issue or not. It is nice to have the extra capacity. One option is retrofit a CS144 alt as some folks have done... but I ignored all those threads as I was always happy with the 94A.

I suppose until the alt upgrade it might be worth checking a few easy things.

Often the ground wires -- fender to battery, engine to frame -- are missing or corroded. Or ground wires are kind of small. They are easy enough to replace. I went ahead and just replaced all of them with larger gauge wiring and went with bigger battery cables too.

It is sort of a PITA to pull the firewall fuse box connector so I wouldn't do that unless I measured a voltage drop between engine bay and cabin.

Maybe it would help to up your idle speed a little bit? That is kind of a band aid though.

If I come up with more info or ideas I will post.

Sent from my XT1096 using Tapatalk

[letank]

Remember that the OEM voltmeter is not the most precise device, check with a voltmeter on the battery, but also on one of the post fused circuit, there will be a difference.

I have a 70A and no AC, no fog lites, but it is above the 13 volt range with headlight and fan on low, my headlights are directly powered from the battery w Rick's relay, so the drop at the dash is not as obvious. Without Rick's system at idle it was dim, but as said above alternator are not designed to give max power at idle, the battery provides the supplement.

Our system are over 25 years old and more for most of us, a little loss is to be expected, some of our wires are internally oxydized.

The 74 has a lower alternator, probably 55A, and I have the Rick's equivalent of remote install relays that I did 18 years ago, it will dim a bit at idle, no problem as soon as it is over 1100 rpm it is good.

I have bypassed the ammeter on both rigs. battery cables are recent and most contacts have been cleaned, and extra ground cable are scattered around

[candymancan]

I would say its pretty fairly accurate if the lights are dimming...