Alternator AC test results

[skyhigh4by]

I’ve been having some minor OD/lockup quirks start showing up lately so figured I would start with an AC test.

 

With truck at idle and minimal electrical load I got 0.053v between battery ground and alternator charge post. Then I decided to turn as much stuff in as I could (max a/c, high beam lights, mirror heaters, etc...) on the test also at idle speed I got 0.1xx volts with constant up and down fluctuation. 

 

So safe to assume that I have diode problems in my alternator likely causing my OD/lockup problems??? 

 

The alternator is only about 5000 miles old and functioning fine so I was thinking I would just install new diode and do the w-t ground mod while I’m at it. 

[Mopar1973Man]

3 minutes ago, skyhigh4by said:

So safe to assume that I have diode problems in my alternator likely causing my OD/lockup problems??? 

 

Yes. Also need to do the W-T ground wire mod.

 

[skyhigh4by]

Is there a sure fire way to tell if the Denso diodes you sell will work in the alternator that I have or is it just a given that they will fit? 

 

Truck is a 98 24v auto 

[Mopar1973Man]

Only two styles...

 

[IBMobile]

Do the W-T ground mod first then test AC voltage again.   Some people have seen a good reduction in voltage after the mod was done and did not need to fool with the alternator diods. 

[Dieselfuture]

^^^^^ what he said, plus your fluctuation in AC noise is from your grids cycling,  unhook them from driver side battery or drive a truck around the block so they cancel out and without shutting the truck off do the same test again

Edited April 2, 2019 by Dieselfuture
Autocorrect

[dripley]

Mine dropped from .035 to .001 on the ground mod alone.

[hdpwipmonkey]

^^^^^ Same

[dripley]

Mine shoud have said .035 to .010. Not .001

[hdpwipmonkey]

Mine is next to nothing with the ground mod now.  When I first checked it with the old alternator it was around .1 IIRC and after replacing the alternator it went down to .03 and after doing the ground mod its barely readable.  Fluctuates between .001 to .002

[JAG1]

1 hour ago, hdpwipmonkey said:

Mine is next to nothing with the ground mod now.  When I first checked it with the old alternator it was around .1 IIRC and after replacing the alternator it went down to .03 and after doing the ground mod its barely readable.  Fluctuates between .001 to .002

Is your trans behaving as it should?

[hdpwipmonkey]

4 hours ago, JAG1 said:

Is your trans behaving as it should?

Yes.  I never had an issue with the trans acting up.  I did the alternator replacement and ground mod as preventative maintenance.

[JAG1]

I used to have hesitating shifts into overdrive on the 02, after the W-T ground mods that is gone.

 

 Dripley found another set of wires that are soldered together with melted plastic (what a thing to do) in the wire harness. I think he said its down by the ECM? I know it somewhere down around there or by the VP44. Anyone know where that is?

[hdpwipmonkey]

2 hours ago, JAG1 said:

 

 Dripley found another set of wires that are soldered together with melted plastic (what a thing to do) in the wire harness. I think he said its down by the ECM? I know it somewhere down around there or by the VP44. Anyone know where that is?

The only ones I saw were the grounds that the W-T mod article talks about.  I think its three black and tan wires crush spliced into a larger gauge black and tan that goes to the passenger battery.  Its located by the VP44.  I has the shrink tube over it with the adhesive in it.

[JAG1]

11 hours ago, hdpwipmonkey said:

The only ones I saw were the grounds that the W-T mod article talks about.  I think its three black and tan wires crush spliced into a larger gauge black and tan that goes to the passenger battery.  Its located by the VP44.  I has the shrink tube over it with the adhesive in it.

Okay thank you. It's the adhesive then that looks like plastic fuse material. I know the adhesive is not conductive like solder. Are you guys thinking like me that dodge short cutted by not using solder?

[dave110]

4 minutes ago, JAG1 said:

 Are you guys thinking like me that dodge short cutted by not using solder?

It's how they recouped all the money spent on the Carter lift pump 

[dripley]

Sensor grounds. About 8" out of the ECM plug. It is shown on the wiring diagram. It also appears to be the style of splice. 

[JAG1]

Thanks Dripley, I thought it was you that discovered that. I will modify that this season sometime.

 

 

[dripley]

I left mine alone. Thought it might have been part of problem with the electrical gremlis I was dealing with. I have no issues other than the MAP sensor going out since I addressed the 5v suppy wire for the sensors. Seems I have issues crop up every time I fix some thing else. Lord knows what I might find after installing the head. I figure it will run in reverse in every gear when I'm done. Maybe we should start a pool.

[IBMobile]

13 hours ago, JAG1 said:

kay thank you. It's the adhesive then that looks like plastic fuse material. I know the adhesive is not conductive like solder. Are you guys thinking like me that dodge short cutted by not using solder?

 

If Dodge used solder then a prop 65 label would have been needed on the dash to sell them in California.