Volt meter drops using anything

Bryon · Post by **Bryon** » Sat Mar 09, 2019 12:45 pm

I have a stock alternator that always seems to get loose-the belts seemed slightly different sizes, so one was always just a little loose. I finally tightened them too tight because I was constantly losing power, the voltage meter was always in the red, and would drop using any electrical component- especially the window. Both belts shredded this morning and I got one belt at AZ because the second had to come from the hub.
So while I’m waiting to replace, I was wondering if it was a good time to install the 84 volt alternator that I have on hand.

Do I need to put any larger wires for hot or ground for this upgrade?

Bryon · Post by **Bryon** » Sat Mar 09, 2019 2:41 pm

Anybody know what this plug is for?

Bryon · Post by **Bryon** » Sat Mar 09, 2019 2:42 pm

This engine was rebuilt and has an EFI distributor

will e · Post by **will e** » Sat Mar 09, 2019 6:03 pm

The plug is for the original distributor (I believe), someone will correct me if I am wrong.

Here is a thread about the belts. http://www.fsjnetwork.com/forum/viewtop ... f=7&t=9576&

Post by **Stuka** » Sat Mar 09, 2019 9:08 pm

I assume you mean 84 AMP alternator.

If you voltage drops easily, it could be a ground issue. Or anything that can cause current to be too high for the alternator to support. As well as loose belts. Put the new belts on, see how it goes. But it may require some more digging.

tgreese · Post by **tgreese** » Tue Mar 12, 2019 7:51 am

Bryon wrote:
Anybody know what this plug is for?

Yes, Motorcraft distributor plug. Green corrosion like that is a common problem for that plug.

TeaBag · Post by **TeaBag** » Tue Mar 12, 2019 2:25 pm

I'm running a 100 amp powermaster. Night and day over the stock. Did not need to upgrade any of the stock wiring. All was in good condition.

Bryon · Post by **Bryon** » Tue Mar 12, 2019 2:37 pm

TeaBag wrote:I'm running a 100 amp powermaster. Night and day over the stock. Did not need to upgrade any of the stock wiring. All was in good condition.

Did it fit right in? I am having trouble getting my 94 amp (can’t remember the brand right now) to fit in. I have ground off parts and edges, but seems to be hitting the oil filter

tgreese · Post by **tgreese** » Wed Mar 13, 2019 7:02 am

Running a larger alternator if you have the ammeter in the dash is a very bad idea. Unless you enjoy dash fires.

Bryon · Post by **Bryon** » Wed Mar 13, 2019 9:14 am

tgreese wrote:Running a larger alternator if you have the ammeter in the dash is a very bad idea. Unless you enjoy dash fires.

Thanks for the heads-up!
I will be bypassing that for now. Do you have an aftermarket ammeter that you recommend for an 89?

I got the 94 amp alternator in, but the adjustment bracket seems to be blocking it a little and it looks like it is at a slight angle. Should I bend the bracket a little, or surrender and get the one from BJ’s?

The new alternator has the engine running MUCH better! It seems the smaller one wasn’t powering the HEI

Post by **Stuka** » Wed Mar 13, 2019 1:13 pm

You do not want an ammeter, you want a volt meter. There is really no reason to have an ammeter in a car.

For the bracket, I guess it depends on which way it is bending. Is the pulley straight?

babywag · Post by **babywag** » Wed Mar 13, 2019 1:20 pm

Bryon wrote:
tgreese wrote:Running a larger alternator if you have the ammeter in the dash is a very bad idea. Unless you enjoy dash fires.
Thanks for the heads-up!
I will be bypassing that for now. Do you have an aftermarket ammeter that you recommend for an 89?

I got the 94 amp alternator in, but the adjustment bracket seems to be blocking it a little and it looks like it is at a slight angle. Should I bend the bracket a little, or surrender and get the one from BJ’s?

The new alternator has the engine running MUCH better! It seems the smaller one wasn’t powering the HEI

An 89 doesn't have an ammeter.

The alternator being crooked is sometimes missing upper small bracket on backside that acts as spacer also.
The lower bracket can also be installed incorrectly.
Sometimes a PO/mechanic will install them wrong.
IIRC it goes on against backside of alt. case.
Seen it a lot due to poor design of brackets people get it wrong.
Do whatever you need to do and get alt. straight so belts line up properly.
You can also order a matched set of belts that will be the same length. It's very hard to get 2 that are exactly the same.

Post by **Stuka** » Wed Mar 13, 2019 3:50 pm

babywag wrote:An 89 doesn't have an ammeter.

Ahh, excellent point. I totally skipped over that.

candymancan · Post by **candymancan** » Sat Mar 16, 2019 7:20 am

On my 90 i installed a 94a alternator on it. Got it at carquest. Fit right in no issues. I dont hsve power dropping ti the redline if i use anything anymorr.. but also if your in gear idle. Power will still drop if you using figs. And ac or heat. Zi had to bump my idle up slightly to compensate.

If i idle is too low it csnt get the juice needed.. So i raised rpms up about 100 or 150 and that helped a BOAT LOAD.. my rpms in gear idle are like 650-700 and park idle is about 1100 or so.

Before it was 550 gear idle and 1000 park. And yes i have a rpm gauge so i know what the rpms are.

Previous owner had a 75 or 70 amp alternator in it.

Also fyi didnt the 89-91s come factor with 90A or 94A alternators ? Im oretty sure Jeep upped the amperage in later years.

So before you do this i would make sure you dont already have one in there.. only the older wagoneers had like thise tiny 60a alternators

TeaBag · Post by **TeaBag** » Tue Mar 19, 2019 10:42 am

If you have the same problem I had, The alternator body was assembled backward from the stock alternator when I received it. I had to take the back off and rotate it 180 dgrs to get it to fit. Put it side by side next to the stock one and you should see the issue right away.

Bryon · Post by **Bryon** » Tue Mar 19, 2019 3:49 pm

TeaBag wrote:If you have the same problem I had, The alternator body was assembled backward from the stock alternator when I received it. I had to take the back off and rotate it 180 dgrs to get it to fit. Put it side by side next to the stock one and you should see the issue right away.

That sounds strange!
Was the wire connection on the wrong side too?
My connection is right next to the wire, if that is something that would change with the back being 180• off

When I have some time, I’m going to mess with the adjustment bracket, it seems to be pushing the alternator in, causing it to be slightly crooked. Looking at others online I noticed the bend out, I wonder if the PO put the wrong one on after the rebuild.

The voltage will be about 4mms above the 13V middle line with nothing running. The drivers window is inconsistent with its draw/speed. It seems to be a little quicker sometimes and the voltage meter will barely drop, but drop steadily the longer I continue lowering the window and bounces right back up when I stop.

I know I’m going to have to go in the door and check out the regulator and motor, but does this sound like a bad ground or a bad motor?

TeaBag · Post by **TeaBag** » Tue Mar 19, 2019 5:07 pm

WRT you voltmeter in the dash-mine sits at about 14 volts with no load-this is with an upgraded power master alternator. It does drop a Volt or two when I activate the windows and other types of accessories but doesn’t drop below 12 1/2 V. It is very sensitive compared to a digital multimeter. I suspect it is a sensitive voltmeter and has a lot to do with where the voltmeter takes it’s reading. If you measure your voltage at the battery with a digital voltmeter when things are operating I think you will find that The variances are not as drastic as the voltmeter on the panel. That’s what I have found. I don’t put a lot of faith in the voltmeter that is in the dash.

candymancan · Post by **candymancan** » Wed Mar 20, 2019 1:12 am

You should measure the voltage going to your interior lights or your power seat or fog lights ect.. Youll find the battery voltage on the battery itself reads 14v but everything on the jeep will read 13 or 12v when being used. Which is actually accurate to the gauge.. at least for me. At my battery i read 14.10v dash reads about 13.5, with the fogs and headlights on the dash drops to about 13v and reading from the headlights its about 13.2v, turning the a/c or blower on medium or full blast with the headlights and fogs on, if im in drive idle voltage will drop below 13v and i can begin to see the headlights dimming and blower motor slowing down, i tested the wiring in the jeep and sure enough voltage was 11.5-12v, but once driving it goes back up to 13v with everything on like that

I also found humidity seems to affect it more, if its raining out my voltage is lower for some reason its weird, thats why i upped my idle by 100rpms. I found pushing the gas ever so slightly to bump the idle up 100 or so at a red light caused the gauge to rise from 12v to 13v and stay there, so i upped idle on the carb to 650-700 in gear. Havent had much of a voltage issue since that.

Bryon · Post by **Bryon** » Tue Mar 26, 2019 4:30 pm

I shimmed the mounting bolt by adding 3 washers to the iron tube behind the top mount. I then mounted the adjusting bracket on the outside of the bracket and filled the space with 3 washers.

This pulled the alternator out a good bit, but I am going to add a couple to the other parts of the mounting bracket to even it all out.

I timed the engine at 38 total advance and it seems to stumble a bit, usually going up even the slightest hill. Just a single hesitation, or even toe or three. It has stalled when cold a couple times too

I want to get over this carb crap and put in an EFI kit. The local 4X4 place said they won’t do a Holley Sniper because it isn’t CARB compliant. I replied with a Howell that is compliant, but haven’t heard back yet.

Any feelings on the Howell?

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