Electrical Issues on 4430

beefey · Oct 22, 2017

I'm having some issues with the batteries staying strong in my 4430 and I'm wondering if the alternator is failing or failed.

What I've done so far:

I've put a multi meter on the battery posts and it reads 13.4 idling and 13.6 @ 1500RPM.

Screw driver does have a magnetic pull against alternator when running @ 1500RPM.

I have included a picture from my 4650 for reference but the 4430 needle is either at the hash marks (RED) in the gauge as pictured or @ 1500RPM is at the second line (BLACK).

This is too low right? Is this likely a ground draw or failed alternator?

Lee B · Oct 22, 2017

You really can't go by that meter at all, they tend to lie to you and the older they get the more they lie. 4630 here has a marked line on it too, 14.5 volts at close to 90 degrees over way into the red. The 'new' good line if you will. Not going to buy a pricey liar to replace it with either.

If you don't have near 15 volts cold start up, your alternator is in need of replacement. It should be +14.5 for at least four minutes from a bone cold start and then settle down to between 13.8 and 14.25 at 1,500 RPM.

New alternator may not solve the issue if you have key off parasitic drain, but you can't really get a good fix on that when the alternator is being lazy as this one certainly measures out to be. Unless your handheld meter is fibbing to you too - which you could test against the pickup battery or any other vehicle for the above stated voltages.

Before you throw good money at a new alternator, investigate every single inch of the big red cable going to the batteries to charge them. It may have a loose connector at the alternator/starter or broken wires limiting the amount of amperage that can flow. Bottom hinge bolt on alternator should be tight for a good ground and the block may need grounding with a dedicated ground strap as well. Something is just not quite right with it when you have those readings. They are about 1/2 volt low and it is important to find where it's being lost.

beefey · Oct 22, 2017

(quoted from post at 22:29:05 10/22/17) You really can't go by that meter at all, they tend to lie to you and the older they get the more they lie. 4630 here has a marked line on it too, 14.5 volts at close to 90 degrees over way into the red. The 'new' good line if you will. Not going to buy a pricey liar to replace it with either.

If you don't have near 15 volts cold start up, your alternator is in need of replacement. It should be +14.5 for at least four minutes from a bone cold start and then settle down to between 13.8 and 14.25 at 1,500 RPM.

New alternator may not solve the issue if you have key off parasitic drain, but you can't really get a good fix on that when the alternator is being lazy as this one certainly measures out to be. Unless your handheld meter is fibbing to you too - which you could test against the pickup battery or any other vehicle for the above stated voltages.

Before you throw good money at a new alternator, investigate every single inch of the big red cable going to the batteries to charge them. It may have a loose connector at the alternator/starter or broken wires limiting the amount of amperage that can flow. Bottom hinge bolt on alternator should be tight for a good ground and the block may need grounding with a dedicated ground strap as well. Something is just not quite right with it when you have those readings. They are about 1/2 volt low and it is important to find where it's being lost.

Thanks Lee! I'll look into those couple things you pointed out. If I bring the alternator into say O'Reily or Napa can I rule it out that it's bad? Does that machine load test the alternator?

Thanks!

beefey · Oct 22, 2017

(quoted from post at 22:29:05 10/22/17) You really can't go by that meter at all, they tend to lie to you and the older they get the more they lie. 4630 here has a marked line on it too, 14.5 volts at close to 90 degrees over way into the red. The 'new' good line if you will. Not going to buy a pricey liar to replace it with either.

If you don't have near 15 volts cold start up, your alternator is in need of replacement. It should be +14.5 for at least four minutes from a bone cold start and then settle down to between 13.8 and 14.25 at 1,500 RPM.

New alternator may not solve the issue if you have key off parasitic drain, but you can't really get a good fix on that when the alternator is being lazy as this one certainly measures out to be. Unless your handheld meter is fibbing to you too - which you could test against the pickup battery or any other vehicle for the above stated voltages.

Before you throw good money at a new alternator, investigate every single inch of the big red cable going to the batteries to charge them. It may have a loose connector at the alternator/starter or broken wires limiting the amount of amperage that can flow. Bottom hinge bolt on alternator should be tight for a good ground and the block may need grounding with a dedicated ground strap as well. Something is just not quite right with it when you have those readings. They are about 1/2 volt low and it is important to find where it's being lost.

Thanks Lee! I'll look into those couple things you pointed out. If I bring the alternator into say O'Reily or Napa can I rule it out that it's bad? Does that machine load test the alternator?

Thanks!

tim s · Oct 23, 2017

To add to what Lee stated some times the small wire that plugs into the alt. breaks off in the loom, and won't let the alt. energize,,you can replace the harness if this is the issue,,or install a one wire alternator,,I choose the one wire alt.

Dave H · Oct 23, 2017

Me, not being a guru on the electrical issues, would take the alt to a shop and have it bench tested and go from there. Doesn't cost a cent at the local Batteries plus.

However, you do have some good direction on the subject.

When you get her fixed, it would be nice to get a reply on the fix.

beefey · Oct 23, 2017

(quoted from post at 07:54:17 10/23/17) Me, not being a guru on the electrical issues, would take the alt to a shop and have it bench tested and go from there. Doesn't cost a cent at the local Batteries plus.

However, you do have some good direction on the subject.

When you get her fixed, it would be nice to get a reply on the fix.

Thanks fellas-- I'll pull the alternator and have it bench tested at the local Napa and report back!

tim s · Oct 23, 2017

My bet is the alt. will test okay..the wire will be broken...

DONMYEIL · Oct 23, 2017

The resister wire in the engine side has most likely broken or corroded . Deere has a replacement that can be added to the loom . Takes some searching in the wire loom page to find it . I have one but not sure the part no. is on it .

beefey · Oct 23, 2017

(quoted from post at 14:39:31 10/23/17) The resister wire in the engine side has most likely broken or corroded . Deere has a replacement that can be added to the loom . Takes some searching in the wire loom page to find it . I have one but not sure the part no. is on it .

Gents, the teenager at AutoZone said he couldn't test it unless he knew what car it went into... :roll:

Anyway I had him run the AC Delco PN stamped on it and he was able to run the test somehow. He said it 'failed'. It made an awful noise in his machine and when I spun the unit with my hand the bearings felt and sounded great. So I think he probably had the belt slipping or something...

Because it's harvest time I was called to rush home and get the tractor fired up. So I installed the allegedly failed alternator back in the tractor.

I fired the tractor up and now the gauge is in the green charge side (about 2:00) on the gauge. I tested the electrical system with a multimeter and now it's hitting 14.4V.

The best I can make of all this is that the signal wire, the positive wire, or the bolt ground must have not been making continuity and when I took it out and put it back in I broke the rust off resuming normal operation.

One last question... There are two small control wires coming off the alternator. One of these wires doesn't go anywhere. It just ends at a black cap tucked up in there under the hood. What is that?

Sorry to be long winded and I really appreciate your help boys!

KYpatriot · Oct 24, 2017

Like Tim S said above you have a broken wire from the alternator that is making intermittent contact . Mine broke where it entered the main wire bundle about a foot above the alternator...the engine fan blowing back vibrates these wires around some and it finally cracked inside the insulation but it wasnt visible from the outside. Sometimes it charged, and sometimes it didnt. I ran new wire and it now works like a champ.

Bob · Oct 24, 2017

"The resister wire in the engine side has most likely broken or corroded . Deere has a replacement that can be added to the loom . Takes some searching in the wire loom page to find it . I have one but not sure the part no. is on it."

To add to what Don said, the "excite" wire to the alternator's #1 terminal was originally a single-strand nichrome resistance wire, which often got brittle and broke. With the lead to #1 broken, the alternator becomes (more or less), a "self-exciting" one-wire alternator, depending upon being in good shape, and a bit of revving the engine to get it to charge. (The other little wire, to the alternator's #2 terminal, is for "remote voltage sensing", connects close to the battery and provides a reference of battery voltage to the alternator.)

As Don said, DEERE sells a kit to replace it with a normal stranded wire and a diode. Awful high priced, tho. You can make one up yourself with a $0.50 1N5408 (or similar) diode and a length of wire.

<img src = "http://jdpc.deere.com/pimages/RP76/RP765__________UN01JAN94.gif">

Key #1, Harness, AR90841, $72.89, Key #2, Rectifer/diode, AR85283, $21.96.

Electrical Issues on 4430

beefey

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Lee B

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beefey

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beefey

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tim s

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Dave H

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beefey

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tim s

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DONMYEIL

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beefey

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KYpatriot

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Bob

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