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2000 Signature Alternator issues after replacement.


engine103

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Engine Electrical Problem

Traveling through South Dakota last week, I began having problems with keeping my generator running while traveling. Soon after this I lost cruise control then noticed that my voltmeter had dropped to zero. Within a few minutes the transmission dropped down to 4th and what I believe went into limp mode which resulted in a top speed of 55MPH. Hoping to press on to Sioux City another 30 /40 mile where we could get some help and avoid a tow.

 As we pulled off the interstate it was obvious that we were about to lose all engine power but were able to make it to the truck parking area where it just died. Across the street was a large truck repair (First State Truck Repair) but we are dead with no starting power. Of course, this was a Sunday, and they were not open. Monday, I called a tow company, but he was relucent to come out for a ¼ mile tow and suggested if I had a jump start box it should get me started and if left connected would get me across the street to the shop, and it did.

“I” told the shop that it was an alternator problem and so they replaced the stock alternator (Cummins ISM 500), with a new alternator but had a problem getting a charge to the batteries and said there may be a problem with the battery isolator, they could replace it or wire around to make it work which I had them do so I could get back on the road.

Now I would like to undo what they did with a new isolator and my rebuilt original alternator. But I need a picture of how the high voltage was connected at the isolator.

Ivan, would you mind posting a picture of the High voltage box to use as a guide? Thanks, Jim

 

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Hey- So I also have an 500 ISM. I just went through a large issue with alternators that caused a lot of digging in other areas all unnecessarily. The alternator you show in the picture is exactly the one someone sold me.  They claim it’s Duvac and it is not!!! I also replaced my isolator which was not needed. You must get a true Duvac alternator. Is that the alternator they replaced? Or is that the old unit?

Edited by Tillman111
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I'm sure Ivan will respond, he is always helpful.   

What I'm wondering is did you find why your generator quit? 

Were you getting low on fuel?                         

Glad you got on the move again

Edited by Ray Davis
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No, that is not the original alternator, that is one they sourced for me. My original is sitting on my bench waiting to go to the shop for rebuild. I had better than 1/2 fuel on board so that was not the problem with the generator shutting down. Basically after the generator quit, I ran until the batteries were exhausted. The jump start pack I used is a Gooloo GT 4000. It gave ne enough juice to start and could go a few miles with just keeping it connected to the batteries. 

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Jim, any chance that you have your system set up so when the house batteries are fully charged the generator will automatically shut down? I think this has been made perfectly clear that you can only use the original alternator ( rebuilt) or find a spare exactly the same and have it rebuilt as a spare, I went through this exactly one year ago , John Hagard was still alive , I believe John and Ivan helped through the issue.Actually my last conversation with John was August 9th last year before he passed away. Sure miss him, kind man, he helped me with our 1950's farm tractors 🚜 that we were selling.

God bless you John.

Wayne 

1999 Signature ceaser 

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The center post is the feed from the alternator. Remove the jumpers from the center post that go to the outside post’s. That will be your stock configuration. The outside post’s go to each bank of batteries, chassis/ house. Hope this helps.

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41 minutes ago, Ivan K said:

Jim, sorry for the delay, really hard to get signal here in North Dakota NP. I am trying but the upload keeps failing.

 North Dakota,  I am so envious.  How is the weather there?   I'm sure you know it's still miseable here in Tx.  I'm renaming my pond Lake Mead, it's way down.         Something like 70 days with no rain.  My well is running non stop trying to keep some grass alive.  We have 3 elect meters and I'm afraid to look at my bill.

 Hope you are having a great time there.

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Hey Ray, the TX weather chased us out a couple weeks ago. It was well over 100F when we left. No better in Oklahoma and Kansas on our way. Iowa a little better. We are dry camping in the two national parks here, better but still hot in daytime, nights are nice though. A couple of days ago we stayed below 60F all day and it was weird, back to 90's again. Stay cool!

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Thanks Ivan and Frank. Sorry for thee upside down pictures but... Ivan there is what appears to be a ground wire from the bottom battery connector over to the side of the case that you don't have. Should I leave that where it is? This is the original alternator to be rebuilt and the box shows what they replaced it with. Thanks, as usual for all the help. Jim

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Jim, if you are going to original setup, the black cable from lower isolator port should not be there, they are jumping the alternator output right to the salesman solenoid and batteries. If you don't have the diagram, I can get it to you tomorrow.

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Here is a ton of files that should help sort it quickly. This is not first rodeo for this problem.

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That new alternator may be fine but you can verify with a couple of quick tests but before that I have a question.

Did you try the emergency start button when things were going downhill, voltage wise? That should have combined the battery banks and with the generator running you should have been able to run all day. 

Sometimes the voltage is so low this will not work so you have to revert to just combining the large wires on one side or the other of the "Bird" relay.

If you have a problem sorting that one out you can use an automotive jumper cable to combine the coach and engine batteries.

Using your jump start device got you moving which is great.

___________________________________--

 

It is apparent they bypassed the isolator which is fine IF they installed an alternator that is capable of regulating itself, and does not need a remote sense wire. 

With the two large jumpers they accomplished two things, which bugs me a bit if they could not or did not tell you if the isolator is really bad. 

They should have measured the voltage on the center post of the isolator. If the running voltage was low or not there then any external regulator setups should be checked. Could be a simple fuse in that circuit.

That is beside the pint and at this stage you can take some simple measurements to see what is going on.

______________________________________________________________

 

Before removing the jumpers which look new and were installed to bypass the  isolator function, measure the voltage on the any of the large posts with the engine running. Should be around 14 volts or so. You can take a reading at the batteries just for future reference as well. Write these down for sure. 

Turn the engine off, turn the batteries off, measure for voltage at those posts again and be sure there is no shoreline or solar powering the coach.

Remove the large jumpers. Turn the batteries back on. Start the generator and give it two minutes to settle down circuits. Measure the voltage on the two outside wires of the isolator. The onboard charger should be alive just as it should on shoreline so you can connecto to shoreline if you wish but getting a measurement with one of those sources at a time will help "reverse engineer' your system. So do both tests if you can.

You should see a good charging voltage on one of the outside posts with either shoreline or generator. 14 volts approx is fine. 

It is kind of important to test both shoreline and generator just to gather information. 

------------------------------------------------------------

Now disconnect shoreline and generator power. Start the coach and after a minute take a measurement on the three posts of the isolator. Post those readings and things should be sorted quicly. 

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Someone will be looking up the old alternator model and should quickly be able to tell if it uses a remote regulator sensor wire or is self excited. I will see what files I have on this. In the mean time will post this before it disappears. 

 

alternator 28SI Delco replacement.jpg

Alternator versus generator.jpg

Delco Alternator remote and non remote sense setup.jpg

1. Alternator explanations for repacements.docx Alternator Diagnostics.pdf Alternator diagram and pre-heat.pdf Alternator picture.pdf Alternator with an isolator not mine.pdf Alternator.pdf AUXILIARY START.pdf BATTERY COMPARTMENT).pdf Battey cables and starter wiring.pdf External regulator on alternator like Leese Neville.pdf Front Run panel Ignition Circuit.pdf Ignition Circuit.pdf Leese Neville starter and alternator.pdf Leese Neville starter.pdf Pre Heat Panel Early version.pdf Pre Heat Panel.pdf Starter.pdf Starting issue voltage readings small front run panel.pdf

Edited by myrontruex
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By "reverse engineering" we should be able to find out if the isolator is bad. One jumper may need to be in place on the engine battery side to satisfy the alternator.

It appears there has been some modification to the coach already with the Ampl-Start device installed nearby as well as some sort of digital readout device. Can't see it clearly.

The Trik-l Start/ Ampl Start device could throw some diagnostics curves into the mix. 

I suspect based on the vintage of your rv that the alternator should have charged all battery banks when things were working as factory, however from shoreline there was not Bi-Directional charging and hence, the install of the little module to charge the engine bank.

The large solenoid is likely you emergency start solenoid which should combine both batteries when the button is pressed. 

Those solenoids fail/wear out often and you could have more than one problem but this is for later diagnosis. You really need that circuit to work. That could have allowed you to finish the trip most likely with the generator purring along doing all the work.

 

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Posted (edited)

Just for information, here is the repair summary. 

 

image.thumb.png.a51b7f8051604e413dbbeb3cf0c2fad2.png 

Tried to delete as very hard to read.

Thanks Ivan very useful!! Myron that's a lot of information and thanks for posting. Being a electrical novice it will take some rereading.

Edited by engine103
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  • Tom Cherry changed the title to 2000 Signature Alternator issues after replacement.

Well based on the very excellent technician write up I believe you are good to go and would not consider rebuilding the old one. Putting it back in would create more headaches for the tech.

They diagnosed the isolator as bad and your alternator may have been good but not likely It is common to have two problems.

So your Alternator should now charge both battery banks.  

But, there is always one huh? The battery banks are no longer isolated so you could run both banks down at the same time now.

I have seen the stuff to the right of the "Booster" solenoid but will have to dig into my archives for a refresher course. It may be as simple as removing one of the large new jumpers they added to bypass the bad isolator. The voltage output from the new alternator is spot on. 

I suspect the jumper from the chassis battery should be left in place and the one that connects to the house batteries could be removed. It would be a very simple test.

Measure both banks of batteries with the engine running. Then after turning off the battery banks and engine, of course, disconnect the one jumper to the house batteries. The new one they installed.  Turn the switches back on and start up the coach. Let it run for a couple of minutes and test the house batteries and engine batteries. If they are very close to the same you should be good to go.

IF this works this way you need to connect to shoreline or use generator to power the onboard charger. Then take measurements again with the engine off and just the shoreline/generator running. You should see a charging voltage on the house batteries near 14 volts. Hopefully, you will see something close to that on the engine batteries. 

What this would indicate is that  there is some kind of additional charging circuit just for those batteries. It was not unusual to NOT have any means to charge them on many coaches. 

When you have no sources of charging power you absolutely need to turn the battery bank switches off. There are lots of draws and in a few days, the batteries can be toasted. 

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Thanks Myron, I think your right at this point leave well enough alone. I did find this excellent post and it may be the way to improve and prevent future problems. Thanks again, Jim

 

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You really need to find out if the batteries are being isolated when no charging voltage is present from the alternator, shoreline, or generator, IF you always have hookups then no worries, and your boost button relay is useless for that function with the current setup.

If you find/found alternator voltage not charging in the future, then starting the generator should keep you going down the road,

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1 hour ago, myrontruex said:

You really need to find out if the batteries are being isolated when no charging voltage is present from the alternator, shoreline, or generator, IF you always have hookups then no worries, and your boost button relay is useless for that function with the current setup.

If you find/found alternator voltage not charging in the future, then starting the generator should keep you going down the road,

I really know enough about isolators to be dangerous.  But our own Van Williams installed a Blue Seas 12VDC ML-ACR.  I may be incorrect.  Frank will chime in.

But this device allows both banks to be charged simultaneously by the inverter/charger and/or Alternator and also replaces the Big Boy 200 A battery boost and has logic to prevent run down.  It is rated at 500A.

https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

  if I replaced my Intellitec BIRD sensing module and the 200 A Big Boy and used the existing control wiring and such, this should  be a Plug and Play that is cheaper than the two Intellitec units.  Obviously way cheaper than a Dynasty PCB board repair and a Big Boy….which would be $600.

I know that may be incorrect….that obviously the PCB board must have other functions….but, on the surface, the standard Blue Seas $281 looks simpler and cheaper.

Just asking a question with an alternative….  CHIME IN…

Thanks

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4 hours ago, Tom Cherry said:

I really know enough about isolators to be dangerous.  But our own Van Williams installed a Blue Seas 12VDC ML-ACR.  I may be incorrect.  Frank will chime in.

But this device allows both banks to be charged simultaneously by the inverter/charger and/or Alternator and also replaces the Big Boy 200 A battery boost and has logic to prevent run down.  It is rated at 500A.

https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A

  if I replaced my Intellitec BIRD sensing module and the 200 A Big Boy and used the existing control wiring and such, this should  be a Plug and Play that is cheaper than the two Intellitec units.  Obviously way cheaper than a Dynasty PCB board repair and a Big Boy….which would be $600.

I know that may be incorrect….that obviously the PCB board must have other functions….but, on the surface, the standard Blue Seas $281 looks simpler and cheaper.

Just asking a question with an alternative….  CHIME IN…

Thanks

I believe Van has the Blue Sea ML-ACR and he will chime in if he sees this post to confirm.  I know Paul Whittle has one installed.  I also have one and it's on my todo list to install this summer.  The one feature I like is the ability to select from the dash switch whether to have the unit in On-Auto-Off mode from a battery boost replacement switch on the dash.  Extra wiring is required so this isn't exactly a big boy plug and play swap.

A while back, Paul had a very informative post with pictures on how to convert from big boy to a blue sea automatic charging relay.  These Blue Sea automatic charging relays are often used on higher end motor yachts.  They are built to last.  I've cleaned my big boy for the last time.

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One more thing, I fully intend to go the Blue Sea ML-ACR route but in the meantime, I have a new isolator that has been sitting on my shelf for a few years and the question is if I undo the jumpers on the old isolator and install the new one, would it function as it should with the new alternator that I now have?

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