The truck I just got is on its 3rd alternator in a couple years according to previous owner, all have had diode failures causing the TC lock/unlock condition. Assuming that a quality high amp alternator is going to last longer than a over the counter replacement unit..

 

I was looking at nations alternators but the one for the 24v diesel looks to have a 2 pin plug on the back of it but mine has 2 ring terminal studs. Im new to dodge and cummins. What am I missing here? Does the 98 24v have one off parts or something??

2 hours ago, W-T said:

Again, grounding with "integrity" with as "short" leads as possible and DO NOT CREATE GROUND LOOPS. You must maintain a single central primary ground source that all grounds will reference to.

I know that Mike advised against this but I added grounds to my truck about 4 years ago before I knew all this. One from passenger side negative to body, one from driver side to frame and one from bottom mounting bolt of alternator to passenger side negative. Is this what you describe as loops and should be avoided. I see no side effects at this time but that doesn't mean it's not there.

@W-T You still missing what I'm saying. 

 

Like right now I've got a good alternator very AC low noise. It will remain that way as long as the grid heaters are not hooked up. So all the noise filtering is a non-issue being there is none at this point. My problem is finding what causes the alternator to overheat the diodes and create the excessive AC noise. The only thing I can see is the grid heaters drawing more than they did when the truck was new. Like I said grid heater are unhooked no issues at all. But I know as soon as I hook them up again now I take the chances of kill the diodes again and creating the AC noise issues. 

 

@Dieselfuture Both of my truck are completely factory wiring and no extra grounds or anything added working just fine. Just without the extra ground, it notifies me sooner of the problem before the AC noise level gets excessive like guys with all the added grounds get the warning too late and the ECM gets cooked.

Edited February 7, 20187 yr by Mopar1973Man

@Dieselfuture No...this is NOT a ground loop. You have done the correct procedure...this is known as "bonding" and is standard Military procedure for "hardening the electronic platform". Any dissimilarity in the intrinsic DC resistance between body, body panels, frame and hood should be eliminated by "bonding" with sufficiently gauged wire or strap. This silences all noise from an electrical standpoint and creates an electrical platform with uniformity. All Military platforms are bonded to extreme levels of efficiency. My compliments to your disciplines of electrical integrity !    

I see your point @Mopar1973Man I do check AC noise kind of regularly, I guess my question is, will it do any damage to any electrical components by having more grounds, or the only risk is not knowing about AC noise sooner

No. But it gives more paths to go. So when the alternator fails a negative side diode and creates a negative hole in the sinewave now it will travel out across the multiple ground straps. Typically in stock form, the warning sign is pretty obvious and noticeable. When people add extra grounds and modify wiring like moving the ground lead away from the alternator now the warning comes much later when AC noise level is critical and the ECM takes the hit. Typically the ECM fails before the owner even knows what happened because of all the wiring modifications. This why I do not suggest the extra grounds, noise filter, tinfoil, etc.  it does mask the problem longer and now you get less warning about the actual problem and damage come sooner. 

 

Remember actually the power flows from the grounds (source of electrons) to the positive side (to where there is lack of electrons - like a vacuum). 

 

Like in every case my alternator failed it was an obvious surge in the cruise control very unsteady. When it got worse it would start to affect the throttle when you manually controlled it would surge beyond what was commanded. Never lost a single ECM or PCM. I've lost my ABS module and had it rebuilt by Module Masters. Actually, come to find out the ABS failed because of a bad tone ring but the was damage done by fighting the system with a bad tone ring.

 

This is why I want to solve the alternator failure issue and not worry about modifying the truck being it worked for over 10 years without a single issue without any wiring modifications. Now, what do I have to fix to get back to that realm? Just like my 1996 Dodge still stock and no modification done to it still working just fine 22 years later. Same power cable ran with all the other stuff to PDC. Doesn't change. 

 

I know someone made a comment about the diodes and the source. I can tell you a Denso is manufactured in Japan. The diodes are also manufactured in Japan. Even the diodes I sell in the M73M store are manufactured in Japan. That is not going to go away.  NJo matter where you go or who remanufactures a stock alternator its going to end up with Japanese diodes. From all my research sourcing out diodes for Denso alternators all come from overseas nothing is made in the USA. 

 

I've talked to several alternator shops and rebuilders and all say the same thing there is nothing wrong with the diodes it has to do with electrical loads that are causing the diodes to overheat. The only huge electrical load on my truck that is "live" during the time the alternator is charging is the grid heaters. Starter doesn't count because during cranking the alternator isn't energized nor is it charging till the tach signal comes up to idle speed.

 

So back around the vicious circle. Back to the diodes overheating. 

Just now, Mopar1973Man said:

 

So back around the vicious circle. Back to the diodes overheating. 

Probably means that I'm just big big trouble maker around here

One thing that has always baffled me. My Chrysler 300M with 3.5L engine, 1 battery and modest electrical load gets a 130A alternator. My 99 Dodge Cummins with 5.9L engine, 2 batteries to charge, and nearly 200A of grid heater load alone gets a 136A alternator  . Why it worked from new and now it doesn't is something I would like to know as well, but our stock alternators do seem quite a bit weak for the work they need to do. Maybe when everything was new it was just so enough amperage output to work OK, but now that things, whatever those things may be got aged and weaker it's just not enough and the poor alt. has to work too hard. In the AC world everything is sized 20% larger by NEC code to allow a little cushion. But here we're sized smaller for some reason. Cost? I mean if you wanted to buy a generator for your house and figured you have an 7800W load you would not buy an 8000W generator right? Common sense would say go with a 10,000W so it don't have to work at full capacity. I know the grids are a momentary load, but that moment gets pretty long when it's cold. So back to the OP's question. Wouldn't a larger amp. alternator be the way to go?

Additional grounding of any mobile, nautical or aircraft is a standard. Most civilian vehicles are produced with bare minimum efforts (budget) but, usually just enough to get by. As time advances all structures that have mobility will develop a loss of electrical continuity especially if it was produced for civilian use. It's difficult to get near or approach a jet black Chevy Suburban with CIA employees commanding the vehicle but, if you could....a close inspection would reveal exceptional electronic communication and data platforms within. A closer examination would reveal exceptional platform preparation done by real electronic black-op technicians who know how to prepare for extreme compromise conditions and having a vehicular failure electronically does not happen. DC continuity of all vehicles does not make specification with only minimal design. Bonding an entire vehicle takes time and effort. ($)

 

The standard common vehicles seen on the road, driven by the average person....goes to work, goes to the store, goes to school and comes home. The vehicle is just the everyday "Joe" device. Now let's put a 130 Amp alternator into this and all electronic aspects become more important. As @JAG1wrote "quoting"  Ohms Law...14 volts X 190 Amps = 2660 Watts of power....this amount of power being dissipated is EXCEPTIONAL ! Yes...there are little foo-foo cars with 100 Amp alternators and ZO-6 Corvettes are very cool but, they do not sink 190 Amps at a single meal. The grids of the Cummins platform require above average DC supplies. The starter in the Corvettes  and the Prius do require considerable current to start the engines. Once running, it's pretty easy....Now a Cummins 5.9 is a bit different, it requires 700 Amps just to run the starter on a cold day. The grids, depending on temperature, have a cycle rate.... Mike...I know you have a better experience with this than I do because of the temperatures where you reside.

 

The time it takes for an old 1960's something with a 55 Amp alternator to develop ground issues, due to current-flow aggravating electrolysis degradation at "contact points" is not even in the same ball park with 130 Amp generators and moments during a cold winter where grid heaters sinking 190 Amps is a reality! These CTD's are real diesel "flame throwers" when it comes to WATTS going on. (I'm trying to be clever)

 

If someone took some needle-nose pliers and precisely inserted the tool into a 120 volt wall socket in the kitchen...I think that would get everyone's attention. Pretty dumb thing to do...yes?

 

Now...this event would only be exciting for a fraction of a second and the circuit-breaker in the house breaker panel will open. Now...this is not something anyone does with a sound mind....yes? OK...we are dealing with Bart Simpson...this little unruly hooligan does it AGAIN ! Now...I think it is time for your guest to leave the house and go home....yes?

 

Now...let us do the math... OHMS LAW front and center:

 

120 volts x 20 Amps (circuit breaker) = 2400 watts !

 

So...it's "hair raising" when Bart Simpson sticks a needle nose pliers into the wall out-let in the kitchen....

 

But....it's NO BIG DEAL when our vehicles sink 190 Amps at 14 volts....let me see which event is transferring more electrons....Holly BajeeBers....the CTD wins !  @2600 WATTS

 

So....I would encourage all interested enthusiasts to examine the standards of Power...the CTD's are very authoritative platforms....it is our "weapon of choice"...they are not for the average "Joe" and require some added diligence on our behalf.

 

Needle nose pliers....test with a VOM...looks like a dead-short to me....my VOM only goes down to .2 Ohms and a dead-short is less than that....yes?

 

VOM at grid terminals on any CTD ....WOW looks like a dead short...but let's do the math.

 

OK lets's say 14 volts (we know that's close) and we know the total current demand is 190 Amps....yes?

 

OHMS LAW to the rescue : R= Voltage/Current....R= Voltage (divided by) Current

14 volts / 190 Amps = 0.0736842 Ohms 

 

I think that is very close to a dead short...it is below what your VOM can read....yes? You need a Wheatstone Bridge to read small amounts of resistance. But, if we have two values, we can do the math for the unknown. Electronics 101

 

So....on a cold day....I think I'm going to go stick a needle-nose pliers into the socket...and it's so fun I think I'll do it more than once...in fact I'm going to do this every winter, 6 days a week for 14 years...oh don't worry my 130 amp alternator will handle this along with my storage batteries.

 

By the way....my wife says Bart can't come over anymore...he is not allowed. She thinks he's going to burn our house down.

 

 

Tongue in cheek...presentation, with great respect to all.

 

Cheers,

  

13 minutes ago, W-T said:

OHMS LAW to the rescue : R= Voltage/Current....R= Voltage (divided by) Current

14 volts / 190 Amps = 0.0736842 Ohms 

 

Now lets say that the load is now increased to 220 Amps. So 14 volts / 220 Amps DC (40 amp increase!) now has a ohms value of 0.0636 Ohms very small change but its possible that this small change is the cause of the increase loads on the alternator and creating more heat on the diodes? 

 

I've seen several trucks where the grid heaters shorted out and things get ugly fast. 

 

Here is something to ponder...

 

Edited February 8, 20187 yr by Mopar1973Man

OK, I'll be the one. What are we pondering there? A pegged gauge and what else. And that's not your truck or it wouldn't have Interstate battery and one of those messy red felt thingys under the post .

1 hour ago, JAG1 said:

Probably means that I'm just big big trouble maker around here

You always have been. Why do we tolerate you.

 

I have  been reading all of this and trying to soak it in. A little hard for my electrically uneducated arse to do. I am on the other end of the stick since I lost my ECM within 7 years. Went out in 08 with only 217k on the clock. No one I spoke to then had a clue of what my problem was. This is how I found my way here. By then I had to pull the trigger and get a rebuilt ECM to fix my problem on my own. Bad experience with the rebuilders but I did end up with a new one from Cummins and not a reman. But now I have 215k on that one and hope I dont have to find another.  So I will keep reading  and learning so hopefully mine will not fail again. Currently my grids have been disconnected for the past 2.5 years.

Grid heaters alternator       

 I love this thread 

2 hours ago, dave110 said:

OK, I'll be the one. What are we pondering there? A pegged gauge and what else. And that's not your truck or it wouldn't have Interstate battery and one of those messy red felt thingys under the post .

 

Your right, but someone's truck having shorting issues with the grid heaters without popping the fusible links. Drawing 400 Amps... That is way more than 190 Amps and not burning the fusible links that is scary...

Oh Wow! I got it now. That is scary! I'd think anything shy of a 1/0 would turn into a fusible link sooner than later at that amperage . What are they supposed to be rated at?

5 minutes ago, dave110 said:

Oh Wow! I got it now. That is scary! I'd think anything shy of a 1/0 would turn into a fusible link sooner than later at that amperage . What are they supposed to be rated at?

 

By George I think he's got it. 

 

That's what I wondering is happening is the grid heater pulling more amperage during it's on periods causing the alternator diodes to overheat and cause the diode failure. Which in turn creates the AC noise issues of the infamous torque converter lock and unlock or like in my case the wild cruise control.

 

Like in this picture measuring 400 amp load and still heating those grids up. That just crazy high loads. But it would be the death of diodes very quickly. 

Edited February 8, 20187 yr by Mopar1973Man

A bit of expense would be involved in this 'test', but how about replacing grids and relays with new and see if the problem goes away?Really isn't much else to go bad in the system other than the heater ground wire. What about that connection? Can't say I've paid much attention to that one.

 A quick E-Bay search shows a new setup can be had for around $200. It's easy for me to spend your money though.

I wish I had the tools to just measure the current load on the grid heaters and see how much mine are drawing then at least know what is going on. Right now I'm on a tight budget with whats going on so tools like this just are not going to happen for me. Replacement without knowing is an expensive gamble too.

2 hours ago, dripley said:

You always have been. Why do we tolerate you.

 

 

 

ME DRIPLEY

You sure you can kick that high? He's like 7ft. tall from the picture I saw.

Sorry, I just had too. The Dave's gotta stick together!