I Think My Alternator is BAD???? Problem solved!!!

[broncoitis]

Well, the conversion to the EFI is done and I have finally driven the truck after it being a work in progress for 10 years. Good Times for sure!

However, some little problems have shown their ugly heads and the most important at this point is the alternator. I think it is going bad. The drive started out well for the most part. Other than being cautious and needing an alignment the truck ran OK. However, about halfway through the ride I noticed that the voltmeter gauge was starting to go down! Instead of showing 14 Volts like it should it was showing less than 11 Volts. Not a good thing at all!

Being that my Dad was following just to be sure that nothing happened he went and got some jumpers while I waited. Looked things over while waiting but all seemed OK for the most part. When he got back, he jumped me and the Bronco fired right back up and again the Alternator seemed to be charging the battery because I could see the Volts go up with increased RPM! Thought all was well but once again the Volts began to drop when all the lights were turned on. Would come back up a bit with the headlights off but drop immediately when I turned them back on! %)

Of all the things that have been replaced for the conversion to the EFI and Explorer Serp the alternator is the only major component that has not been replaced and I have no idea how old it is unfortunately. I think it needs to be replaced!

Any other thoughts?????

 

[Viperwolf1]

Check for 12V on the green wire at the plug with the key on.

 

[ransil]

make sure the alternator case is grounded

 

[Broncobowsher]

Alternators are not always good/bad. There are times there can be internal problems and they slightly work. Loose a winding or diode and a 60 amp alternator can still work as a 20 amp unit. I have had this before and it is enough to keep up with a running EFI engine but turn the headlights on and it goes down.

 

[kaw550]

Is it the factory gauge? Was it switched over to a voltmeter?

 

[broncoitis]

I guess it could possibly be the ground! Right now it is grounded through the brackets and bolts to the engine. The engine brackets are powdercoated. I wiil run a nice heavy wire and see where that gets me,

 

[broncoitis]

Is it the factory gauge? Was it switched over to a voltmeter?

Yes, it is avoltmeter gauge. Autometer cobalt series.

 

[Bronco73]

I bought a wrecked 98 montaineer several years back that had been wrecked. it sat with no hood on it to cover the engine. When I rebuilt it, which I am still driving today the alt was not chargign well. I took it to the local guy who rebuilds alts and he said it was fine and that the case had corrision from sitting in the weather. I ran a heavy guage wire and grounded it to the alt bracket bolt and then to the battery ground and it has been charging for roughly 6 years now like that. I bought it with 72K miles and I'm almost at 150K miles.

 

[broncoitis]

Yeah, I hope that it is the Ground on the alternator that is the problem. This alternator sat for a good 2 plus years before I purchased it and it had the white stuff all over the aluminum housing as a result.

Is the alternator usually grounded from the factory or is the braketry usually enough to get the job done? Im thinking that it was probably grounded from the factory on that one stud with the bolt on top.

 

[Bronco73]

Same issue I had and I figure the bracket to the engine had to be just as bad. The alt repair guy told me to run the ground wire and it worked great.

 

[broncoitis]

Well, I hope that it is as simple as that because I really don't wanna take all the crap off to replace the alternator.

Funny thing about this little problem is that it has revealed some flaws in my radiator shroud that I overlooked! Namely, there is no way in HELL that I can see any way to get the belt off without having to remove the shroud. Secondly, because I wanted the upper radiator hose to be nice and tight so as to avoid any contact with the belt I came up with a very simple fix that works really well! Only problem is that I cannot remove the shroud without removing the upper radiator hose. Oops! LOL!!!

This shroud may just end up being two pieces after all! ;D

 

[Bronco73]

Two piece shrouds makes working on any car/truck a lot easier.

 

[Viperwolf1]

I don't think it's a grounding issue. If it was you would see the problem just after starting when the battery is drawing more amps.

 

[Jedhead]

I also had issues with my alt as well. use the site to your advantage, there are guys who will help you, PM viperwolf, an electrical guru with some info and I'm sure you will get through it, it worked for me and their knowledge that they are willing to share is of great value. That is what this board is all about and thanks to all who have the knowledge and are willing to share it!

 

[broncoitis]

I also had issues with my alt as well. use the site to your advantage, there are guys who will help you, PM viperwolf, an electrical guru with some info and I'm sure you will get through it, it worked for me and their knowledge that they are willing to share is of great value. That is what this board is all about and thanks to all who have the knowledge and are willing to share it!

X2 on that for sure! That is what makes this site so great. Alot of great members willing to share the knowledge or just give you ideas based on what they have done. It has honestly for me made all the difference getting the truck done and the joy of owning it even better! Thanks to all on here!

 

[broncoitis]

I don't think it's a grounding issue. If it was you would see the problem just after starting when the battery is drawing more amps.

Phil,

What you thinkin? Thought that I had the alternator charging figured out but doesn't seem so! Damn! I have to get the voltmeter to test the green wire coming off the RJM harness. At least that is what I think you are talking about.

Anyway, I made up a quickie ground out of some 8 or 10 ga wire and crimped it to a pigtail coming off the negative on the battery and wrapped it around the stud on top of the mounting bolt with mixed results. I had to jump the truck to get it started but I don't think that it really helped much to be honest. My understanding with the alternator is that it should immediately show 14 volts on the gauge and once I got it running never really maintained 14 volts. Would hit 14 when I hit the gas but come back down once the RPM's came down.

Thoughts?

 

[Viperwolf1]

I think it could be a problem inside the alternator, corrosion at the regulator causing the intermittent charging. The fact that you can jump start it shows the battery cables are in decent shape to handle the large current. If they can handle that they should be able to handle the charging current. Only other thing is the excitation current at the RJM green wire. If it's 12V and reliable the problem has to be in the alternator or battery.

 

[broncoitis]

Phil,

I will say that the alternator was covered with the corrosive material when I got it. The Junkyard said that the truck had been sitting for close to 2 years.
In terms of the battery cables and everything else, they are brand new as is the RJM harness.

I will check the voltage from the green wire on the RJM harness tomorrow. Does the computer have anything to do with it? Could that be the issue?

Just to confirm, I should read 12V off the green with the key in the on position! Damn, I shoulda just replaced the fricken Alternator!

 

[Viperwolf1]

ECM has nothing to do with the green wire. It gets power from the O2 relay, which is energized by the ign sw.

 

[broncoitis]

Ok, here is the latest info! Charged the battery up a bit and it is reading about 12.43 Volts across the terminals right now. With the ignition key turned on, I get something like 12.04 Volts off of the Green wire on the RJM harness plugged into the Explorer 4G alternator.

Any ideas what the problem might be with the alternator? Is the regulator bad and not working properly?

Any and all advice considered to remedy this problem!