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??

3 hours ago, W-T said:

The 12 volts input to the coil now becomes a 50 volt back-fart into your control device. 

@W-T you're right about the voltage spike. The proper relay is a must for system protection.  When I was at the Volvo factory school the instructor demonstrated voltage surge of over 100 VDC in a 12 volt system by just disconnecting the fuel injection control module.  The battery should also be disconnected before unplugging or reattaching any module for this resound.

 

@Mopar1973Man said these problems didn't start for the first 10 years.  May be it took 10+ years for a cumulative effect of  corrosion, factory  paint resistance and poorly maintained connections allowing the AC ripple to have an evict on the more sensitive parts of the electrical system.     

 

W-T, I've been to Paradise, CA a few years back when my son was at Chico State.  It's really a nice little town in the hills.l

57 minutes ago, IBMobile said:

@Mopar1973Man said these problems didn't start for the first 10 years.  May be it took 10+ years for a cumulative effect of  corrosion, factory  paint resistance and poorly maintained connections allowing the AC ripple to have an evict on the more sensitive parts of the electrical system.     

 

Yeah that my point if I leave my grid heater disconnected I'll never have another alternator problem ever. The point is something is placing excessive load on the alternator causing the diodes to overheat and fail then the AC noise is the result of the diodes overheating. So my point is what is causing the diodes to get hot and overheat? The only load in the entire system is either the grid heaters banging away on the alternator at idle or batteries that have little to no capacity left and require constant charging because of shorted cells. Batteries are in good condition yet so it lead me back to the loads. The only one that could be creating the overheat is the grid heaters. 

 

Reason, I keep coming back to this is my 1996 Dodge Ram 1500 is still running the factory OEM alternator for 22 years and 169k miles and never been replaced. Same darn alternator being its a Denso. Smaller starter loads and no grid heaters. Never had a TQ Conv. lock and unlock issue on that truck from day one. Yeap... It got a 46RE transmission. So why is it this truck has a factory OEM alternator for 22 years?

 

Again this shows excessive loads are the cause of the diode failure from overheating. Still only occurred after 10 years. So what load wise has changed... 

Edited February 4, 20187 yr by Mopar1973Man

I can't help but wonder what if this grounding thing with the alternator bracket has anything to do with head gasket failure that most experience by thermostat housing. Maybe there is a connection there, electrolysis or something along those lines 

58 minutes ago, Dieselfuture said:

Maybe there is a connection there, electrolysis or something along those lines 

I see this type of head gasket failure all the time in older Volvo engines.  The head gasket is eaten away buy electrolysis and always by #1 or #4 cylinder in the 4 cylinder engine, #6 cylinder in the straight 6 engines.

Howdy thought I'd chime in ,Jag1 the reason your having trouble soldering is the copper wire is drawing the heat away take a small gator clip and clip it on the insulation side like a heat sink in reverse also use flux and I've solved the actual ripple deal I'm just waiting on my oscilloscope to arrive for hard evidence I don't trust meters for this. As soon as I can post my proof I will and it does work I'm running a setup on my suburban right now the alt is way out spitting .21vac at idle and I'm filtering down to .0012 and I've solved the grid heater prob as well

@W-T So that alternator drops right into the factory spot, and doesn’t need a different pulley or anything? If so, mighty impressive. 

 

It really seems as thought the problem is the grid heaters. What else could it be really? Mikes example of his 96 is pretty solid evidence that the same alternator in an application without grids works for that long! Only other factor could be weak batteries and the charging they’d need.

 

I think @W-T has got the fix for anyone wanting to keep using grids and not have issues in the future. 

3 hours ago, notlimah said:

It really seems as thought the problem is the grid heaters. What else could it be really? Mikes example of his 96 is pretty solid evidence that the same alternator in an application without grids works for that long! Only other factor could be weak batteries and the charging they’d need

 

Now twist that around some more...

 

So why did my Dodge Cummins truck run the first 10 years without a single alternator problem and now I can keep an alternator long that about 4 months to a year with the grid heaters hooked up? This current alternator I left my grid heaters unhooked and replaced my block heater for cold morning starts. Now I'm looking for what has changed. Did the grid heater suddenly start drawing more current? I could have said that all my old light was a cause with sport headlights (4 x 60w) and (4 x 100w) driving light that's all gone and replaced by (2 x 35w) Morimoto HID headlights and (2 x 18w) PIAA driving lights. No boombox stereo. No 10,000-pound winch. I don't have tons of junk tied to the positive post of the battery like most do. (Quadzilla, AirDog, ACC to the cab inside the PDC). I just don't have any loads that would cause a diode overheat other than the grid heaters themselves. Here we are back to what has changed about the grid heaters in the last little bit of time that now has the strength to wipe out alternator diodes that weren't there 10 years ago?

My Grids on both trucks show almost zero Ohms resistance. They are an 01 and an 02 truck. One has 201,000 miles and the other has 94,000 miles. Both show exactly the same resistance value with the Fluke. Could it be deterioration of the overall electrical system with more cheaply made rebuild parts inside the alternator?

 

W-T taught me quite a bit on the phone..... forgive me as its all his fault, LOL, but when you do  use the grids your just hammering the snot out of that little alternator. Grids drawing 190 amps X 14 volts = 2660 watts. Like he says that's a hell of a lot of welder... enough to turn my framing hammer into a liquid. Then add whatever else is being used from starter, lift pump, dash lights etc.

@Mopar1973Man what alternators are you using, name? If so who's to say they aren't as junk as any part store one. I see all the points you guys are making, Just thinking out loud.

That's my point. Newer electronics are made in China including diodes so tolerance is ****

 

Now twist it around some more yet. Why did my PSD go through only 1 alternator in 14 years? Only replaced because it quit charging. Dropped a Napa in and back on the road. Did not check for AC noise. Never even heard of it until I got this Dodge Cummins. Never an electronic issue. And those glow plugs draw alot of amps too. Take my 2002 300M. Original alternator and never an issue. My 03 Tahoe same thing. Original alt. and zero issues. But yet I check AC noise on this truck as much as I do tire pressure because on the issues they have. Don't crucify me for calling out Dodge Cummins here. I like my truck. But it seems like they have most of the AC noise problems. Now those who drink the blue Koolaid will say they all have the same trouble yada, yada, yada. Really? I have owned all of the big 3 and have only had this issue with 1, although I'm sure all have had an issue to some extent. I only bring this up to think outside the box. What's different with these trucks? Like @notlimah said the grid heaters are all I can think of. A rebuilt alternator for a Chevy is the same Chinese junk as a rebuilt for a Dodge and yet the Chevy has little if any issues with it that I'm aware of. Just thinking aloud. I'm going to keep my grids on a switch and only use when necessary. That's the best I can think of right now. The whole thing just baffles me.

@Mopar1973Man It could just be other parts deteriorating. Could be grid heater itself, the relay, wiring it’s just harder to diagnose those smaller things. Also could be that parts just aren’t made like they used too. 

Maybe I am one in a thousand, but I am still running on original alternator at over 300k, and never have disconnected my grids, even in the summer they come on in the mornings and work pretty hard in the winter, I have just left them alone and let them do their thing. I know they are working because they pull the volt gauge down to about 9v when on. But altenator still kicks back to14v. and AC noise is still within tolerances, only thing I’ve done is replace battery cables, clean block grounds and other basic maintenance, I will probably do more now from reading @W-T post, but other than that it ain’t broke so I’m not going to fix it by disconnecting the grids, they been working for the last 16 years, other than being on my 4th set of batteries, but at the first sign of weekness I usually replace them and if they got a little life left I will run them in something else like the tractor or plow truck until they completely go out.

 

I know I can’t be easy on the alternator by dragging the 5ver around with all the extra lights and charging the RV batteries periodically. So I don’t know why or how just sayin maybe thier is other internal issues rather than blaming the grids, even though they do draw a lot of power it’s not for a prolonged amount of time.

Man I've got a 96 k2500 w an aftermarket alt been on since 12 it's pumping .21vac at idle it's my test bed for my filter deal and I have solved that problem but I need to prove it before I go further but it's just newer stuff in the reman world sucks and yes maybe Dodge is more sensitive idk not enough input for data 

3 hours ago, notlimah said:

@Mopar1973Man It could just be other parts deteriorating. Could be grid heater itself, the relay, wiring it’s just harder to diagnose those smaller things. Also could be that parts just aren’t made like they used too. 

Like I said both my trucks grids have very low Ohms resistance. The 94,000 mile grids show .3 ohms and the 200,000 mile truck shows the same on the Fluke meter. This indicates little deterioration of the grids.

 

A lot has to do with the high amp draw of healthy grids (190 amps) and the starter placing a big momentary load on the batteries, trying to recharge and keeping up with the high amp load, that little alternator is getting hot and hammered. Combine that with less expensive alternator rebuild parts, improper alternator ground, an aging electrical system and OEM wiring  .... Well then you have it.

 

With two trucks I'm best off  not using grids and plug in the block heater when needed.

 

Thanks to W-T my understanding has got me well grounded.  further explaining  how electrolisys (sp) sets itself up on a ground connection and accelerates the deterioration rate. It is made worse by moisture, unlike metals and trying to squeeze all those electrons thru a tiny portion of once was a good ground or easier electron pathway.

Edited February 7, 20187 yr by JAG1

I’m not entirely convinced that Cummins engineers designed a system this flawed. I just think they didn’t expect people to be using these trucks as long as we are and just as time progresses, parts become outsourced to other countries and quality drops, so does the longevity. 

 

I think a mostly stock (electrically speaking) truck with a well made alternator, new/like new wiring, grid heater within tolerances, all connections/grounds cleaned and good batteries will work just fine for a long time as proven by a few of you. It’s pesky ol time that’s making this equation difficult. 

 

I still think the grid cycling is tough on the entire system given how much power it’s producing. Keeping quality parts going into these trucks isn’t as easy as it used to be and that might be the ultimate issue.

I know... it's amazing how parts get more costly and at the same time  made with lesser quality.

 

I don't mean to contradict Michael Nelson .... I just learned these things recently and am excited how much my understanding has increased. Posting about it helps me put down what I've learned and to share

During my research onac ripple I came across an interesting bit in an unlikely place. The big stereo crowd has a saying called the big 3 , basicly if your gonna run a lot of amps replace the batteries cables and alternator with stouter stuff which thinking back you couldn't buy a 240 or 320 amp alternator back in 01 and you can now he'll my dad's 16 f350 has like a 240 amp alt on it just think maybe that's part of what needs done

10 hours ago, notlimah said:

 

 

I still think the grid cycling is tough on the entire system given how much power it’s producing. Keeping quality parts going into these trucks isn’t as easy as it used to be and that might be the ultimate issue.

I agree with you @notlimah on using quality parts and keeping the connections up to par.  If my alternator was to go out tomorrow the first thing I would want do is find a reputable rebuilder to rebuild it as good or better than factory but unfortionatly those people are hard to find these days. Probably due to the availability and price of the chain store junk. but I still think disconnecting the grids is not fixing the problem just basically masking over it, for quality parts should be able to overcome the burden that the grids place on the system at start up.

On 2/6/2018 at 1:21 AM, notlimah said:

@W-T So that alternator drops right into the factory spot, and doesn’t need a different pulley or anything? If so, mighty impressive.

@notlimah...yes DC Power Engineering produces this to maintain factory aspects of mounting the alternator and using the factory serpentine belt.

 

Again, this alternator is superior in design to all other manufactured devices. My purpose is:

 

1) Eliminate the TC lock and unlock issue ( due to out of spec AC component from the factory Denso). The small AC ripple from all alternators is "smoothed" by the battery(s) however; time takes the toll on the grounding integrity of the entire system.

 

2) Provide additional current on demand when needed. ( I operate some high demand current devices)

 

@outlaw7 The method of providing additional "filtering" is not without merit however; the parallel batteries have great capacitance to dampen slow or moderate AC excursions due to poor DC rectification issues. Large wet cell batteries do an excellent job of "filtering" but, it occasionally is not enough. The primary inspection must begin at the generating source and then follow the path of filtering (smoothing) to achieve the results of "clean DC".

 

In working with "audio" I'm sure you're well versed with "cross over networks" where the audio content is directed to specific speakers. The cross-over is "frequency" specific for certain segments of the desired audio spectrum. In building the cross over network you choose a component structure that "passes" bass but, is not electrically sympathetic or conducive to pass the "audio energy" from a high frequency treble instrument. Following this example in your knowledge base of audio lends well to this subject matter. 

 

The AC component that cause the TC lock and unlock syndrome is a "higher frequency" excursion. Where the activation of the headlight switch to provide current flow is a "slow" human function of activating the switch. This one time action is causing current to flow but, the "initial turn on" IS, the fractional moment when the system is taxed for only a single momentary event. No problem...that small "spike" was absorbed by the eminence capacity of our large storage batteries....and if all is well the headlights are illuminating the road before us.

 

Now...knowing the clock-speed from the PCU...that is controlling the the torque converter... is a "pulse-width-modulated" DC square-wave. This wave form is turning on and off at a very fast speed compared to a human turning on a light switch. How fast is it...?...I don't know but, let us say it's perhaps 120 KHz (on and off 120,000 times a second) this of course,is way faster than a human could turn on and off a headlight switch.

 

Now...audio is relatively slow compared to the control pulses emanating from within the computer control of our trucks and when you select capacitors for the "low frequency" path of the cross over network you would choose components that have the capacitive reactance or to  "favor" the lower ( or bass ) signals. The batteries in our trucks act as very "large capacitors" ...I do not want to say "Farads" but, this could be used to correlate a comparison. The "problem" is the interfering AC ripple that is combing with the PCU's primary "clock" and causing the torque converter to lock and unlock is an unwanted high frequency signal. To dampen or eliminate this "interfering" signal much smaller capacitence values would be the key. Adding "Farads" will not help this situation...adding micro-farads may very well help. The parallel batteries ARE our "low frequency" filters or perhaps a better unscientific term "big slow "reactive" garbage cans".

 

@Mopar1973Manhas reiterated this many times...the truck was fine for so many years... what happened? His research took us all, to the "source" of this unwanted noise. Yes, the alternator is the generating source and the diodes aging, tough environment to endure, good grounds that have deteriorated over time, extreme current demands (grids) at intermittent moments. All of these contribute to a small error...the small AC ripple component is really no big deal...now, let's put a large #6 wire on the alternator's output B+ post...for giggles...let's make this wire 5 feet long and direct this "antenna" into plastic conduit containing other small "signal" sensor wires...direct the physical path of this #6 B+ charge wire, all the way across the front of the engine compartment and terminate this "antenna" into the Master Power Distribution Center with NO by-passing or attention to "possible" extraneous and unwanted noise (ripple) that might occur at some point in time? Bottom line by Mike Nelson...excessive AC ripple is the problem, period !

 

While we are at it (commencing in a parade of electronic buffoonery) let us take four rather key ground wires (all within this "front engine conduit") splice these four and connect them to a black/tan stripe #8 and run this back across the front of the engine compartment stopping to couple and uncouple THREE times in very nice connectors only to finally terminate at the PCU. All standards for "DC Ground"...you shall run the lead as short as possible and terminate with integrity. 

 

Note...the term "antenna" I am using this because a solid perfect DC line does not "radiate" a signal...an AC wave-form imposed onto a piece of wire does act as an antenna and will impose this signal onto and into any surrounding conductive structures. This AC wave-form ( ripple) has a fundamental frequency (3 phase rectification) with a spinning revolution of 700 RPM...1400 RPM or 2000 RPM....??? The frequency varies with condition....this frequency is high in nature...the PCU's clock (oscillator) is high in nature...it is the imposed mathematical equation of two fundamental frequencies "mixing" together as a product. The PCU can not differentiate the correct signal once an interfering extraneous source enters the equation.  You and I experience a transmission with bad manors.

 

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.

 

If your generator has the potential to produce high current (anything over 90 Amps) the stakes are now elevated to arc-welder status and your disciplines must be keen. 

 

These CTD's were produced reasonably and for the most part serve well with competent maintenance. The engineers who planned this out are exceptional individuals... from a standpoint of "what if" we have a little "ripple" on our B+ line...what would happen? They all confirmed that most likely there would be NO issue. These are civilian motor vehicles...we need not worry about subtle errors...they will correct themselves. 

 

Viewing the outright grievous errors in basic "DC 101" theory...I give these men a D- as for all else...I love this truck. After 18 years of service it is excellent however; I'm going to correct these small errors and with the help of the members on this web site, I believe things will only get better. 

 

Sorry...I've seen many questions semi directed my way and I'm trying to catch up...my apologies...I'll continue to address this as time goes forward.

 

As I close out for now...build your Power Supply with the integrity that you expect from the circuits that demand current. A poorly designed power supply will plague all else that you prize. A well built power supply provides years and years of trouble free service....if it is built marginally than all else is marginalized.