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THE ALAMO · 11-09-2021, 09:08 AM

Hello I have a 97 HR imperial 40 ft roadmaster chassis .
8.3cummins turbo 325hp.

I was i going north i69 towards flint mi early evening started getting dark and suddenly I watched the volts on the gadge slowly go from over 12 to almost zero. Lights went dim and Allison trans went into some sort if limp mode .
Pulled Into haslett mi. And shut it down. Coach batteries 6 volts shot so was the charge selinoid. Chassis batteries I only run with one 12 volt 950. CCA. It was dead. Recently put in q new alternator and everything was back to normal prior to this 3 months back..
Salvaged the chassis battery hot it back to where it would hold 12. 6 volts. Never did get a load test or Amp reading.
Tried to start it and the starter took off and would hardly turn over the motor turned key back to on and the starter kept spinning like crazy . I run back shut both main battery switches off and still starter kept spinning until I disconnected disconnected battery outright. Those main battery switches are brand new 2 months old.. now I'm stuck. .what is the problem here? I checked cleaned everything I could see. Connections.
My FUEL SHUT OFF SELINOID IS INTERMITTQNTLY bad. Sometimes I have to push it up so I can start it.

Suggestions as to where to start to finish is greatly appreciated.. I'm not much for electrical but I see I'm learning slowly .. trouble shooting is not my bag yet here. So someone sound off and guide me please..

Unplanned Tourist · 11-09-2021, 11:54 AM

Have you checked the ground cable from engine to frame, and from batteries to frame?

If there's a poor ground, it will drop the voltage, and cause excess heat from the low voltage at relays, etc.

Also, if the alternator is sensing a low voltage, it may cause the regulator to fail early.

OkieSVT · 11-09-2021, 12:22 PM

Quote:

Originally Posted by THE ALAMO

Hello I have a 97 HR imperial 40 ft roadmaster chassis .
8.3cummins turbo 325hp.

I was i going north i69 towards flint mi early evening started getting dark and suddenly I watched the volts on the gadge slowly go from over 12 to almost zero. Lights went dim and Allison trans went into some sort if limp mode .
Pulled Into haslett mi. And shut it down. Coach batteries 6 volts shot so was the charge selinoid. Chassis batteries I only run with one 12 volt 950. CCA. It was dead. Recently put in q new alternator and everything was back to normal prior to this 3 months back..
Salvaged the chassis battery hot it back to where it would hold 12. 6 volts. Never did get a load test or Amp reading.
Tried to start it and the starter took off and would hardly turn over the motor turned key back to on and the starter kept spinning like crazy . I run back shut both main battery switches off and still starter kept spinning until I disconnected disconnected battery outright. Those main battery switches are brand new 2 months old.. now I'm stuck. .what is the problem here? I checked cleaned everything I could see. Connections.
My FUEL SHUT OFF SELINOID IS INTERMITTQNTLY bad. Sometimes I have to push it up so I can start it.

Suggestions as to where to start to finish is greatly appreciated.. I'm not much for electrical but I see I'm learning slowly .. trouble shooting is not my bag yet here. So someone sound off and guide me please..

I would be looking at that alternator you put on it. If the alternator is working properly, both sets of batteries should be charged/charging going down the road. Sounds like you lost power while driving which indicates alternator failure. Take it off and have it tested, or test it yourself. A 950 CCA battery should not be used for operating coach electrical items. That's a starting battery and not the best choice for your coach.

Let us know what you find out.

twinboat · 11-09-2021, 12:25 PM

You may be using the wrong alternator for that rig. It will overcharge, boiling out the batteries until it overheats and fails.

You need a Duvac alternator.

As far as the starter sticking, it's huge cables don't go thru your battery disconnect switchs, that's why it kept cranking.

Weak batteries tend to weld the contacts inside the starter solenoid, causing them to crank like that. A good smack on the solenoid can get them un-welded but damage is done.

153stars · 11-10-2021, 08:04 AM

To be clear......your starter spun but was not engaged cranking and would not stop spinning until removing a cable.
Like already mentioned clean all grounds and battery cables. I have ground at starter as well. Sounds like you had an intermittent connection that created your issue.
If starter kept spinning, sounds like starter Bendix solenoid on starter contacts welded closed but starter gear was not engaged, pulled with solenoid engaging lever fork .
There is also a smaller pilot solenoid that powers the starter solenoid magnet only it could also become stuck closed but I would suspect the starter to be cranking normally.

153stars · 11-11-2021, 10:04 AM

Also your fuel solenoid can replaced with quality aftermarket cheap and in an hour or less. Kits even replace plates.

THE ALAMO · 11-14-2021, 01:56 AM

Yes all grounds that I have found I would unhook and completely clean.
Engine grounds, starter to frame grounds, and any other small wiring I found that was connected to frame on process was cleaned and provided new connectors when applicable and reconnected. Including all positive connections. There is a small ground bar I'm assuming mounted The frame in the engine compartment where about 15 small wires are connected to it. And this area has me puzzled. The bank of wires connected to this ground bar I have no idea where all this comes from. It's location is right where you open the access panel to engine compartment from the outside mounted to the first crossmember of the engine framework.
Now as your looking into the compartment from the rear of the rv down the right side of the motor there is a mess of a wiring harness and in that mess I found one small black wire broken and haven't yet located the other end. Yet.
It seems like I may have to tear the whole 12 volt wiring system apart. What are your thoughts? There is also a what looks like some sort of relay or selinoid (gold in color) on top of the valve cover that is near the fuel system. With 2 connectors sticking out of the top that has no wiring to it. The1997 mechanical (thank god)cummins 8.3 turbo still runs but I was wondering wtf and why this is there .

THE ALAMO · 11-14-2021, 02:26 AM

ZThanks twinboat. Yes it was a duvac alternator and when I put it in it was showing a strong hi 14 volts on my gauge up front so I felt good with that. I also took the plug and stuck 4 six volt batteries in the bat trey for the house. But I always ran with only one 12 volt 950 CCA for the starter. 5 batteries all together. I thought I was in good shape at that point.
Now I have found that that heavy duty selinoid that charges both battery banks through the bird system may be suspect.. well I know for a fact that that heavy duty selinoid needs replaced. But how do do check the bird system..or should I delete it and go with battery chargers.
my concern is the sense wire coming off the alternator.. where does that run to..
After all my researching the last year and a half. It has been a long expensive road but its worth it to me.

THE ALAMO · 11-14-2021, 02:36 AM

Yes there is a large negative wire 16 inches I'm length that comes off from the front of the starter and is connected directly to the frame next to it. Cleaned and reattached. Should I pull the starter and have it checked. It seems to be weak I got 5he engine started but I had to pour the amps to.it with my charger. I also realized that when it started the stater did not keep spinning.. whTs thay about. And is this a sign to add another 12 volt battery to the chassis instead of one. I never had a problem till now with this. (Weak starter?)
Also doesn't the fuel shutoff run off off starter wire that runs off the ignition switch to start the engine? Could that have any effect with the starter process robbing amperage from the starter ?

THE ALAMO · 11-14-2021, 02:49 AM

Man I hope i can get this beast back to its original state or qtleast close. I love this battleship and I purchased it with money I got when my mother passed so it's a total gem in all ways to me. I love rv ing and want to get back to full timing I did it for 3 months last year. And I'm not looking back .. got my windows replaced and one leaked bad when finished and shorted alot of my 12 volt system out last winter during thaw. Insurance would not cover it.right now I just want it back to road worthy and confident.they were installed by a company in the flint area.

153stars · 12-01-2021, 11:18 PM

I'm not HR guy but IRD & BIRD were added in later years from my understanding. Not that it couldn't be added later or a smaller chassis charging device used/added there are several types Lambert being one looks like green heatsink. Most just had diode battery isolator/combiner . These only charge house batts off of alternator. The big combiner / boost solenoid used is like a jump starter , if she's cranking slow try to use switch on left dash to combine to house batts. Keep holding it for 20-30 seconds and try to start it. These do fail and may not boost well or at all. Big diesels like two batteries. Preheat pulls a lot amps too.