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ricelake922's avatar
ricelake922
Explorer
Nov 16, 2016

Travelling to Florida by tow truck

Hello. I have a 1996 Monaco Dynasty. I left Ontario on Saturday November 5th and made it to Ohio where I bedded down for the night at a KOA. Left Sunday morning and had just passed the Ohio Kentucky border when I started to lose power at the throttle. The transmission move from a 6 to a 5, 4 and then 3rd. I inched up a small hill and down with the transmission then moved up to a 5 and up the hill went down to a 3 with no power at throttle. Engine was still running...fuel pump still working but no power at throttle. I heard a clicking sound at back of engine right side which stopped. I had the RV towed to Cummins in Ohio. They could not find any problems as the RV was working fine. I had them perform a Diode test but the RV shut down. The king cruise box was assessed with king cruise and the box needed to be rebuilt. Sent box to Minnesota and put rebuilt into RV. Test drove for 1hour and all seemed fine. Left OHIO and made it into Tenessee when the RV lost power again. Same as Ohio but this time I could get the engine to reve up but no power to move forward. Now at Cummins in Tennessee. The alternator is reading 13.8 amps. The battery line from battery isolator to wet cell battery is at 13. 8 amps. The battery line from battery isolator to 12V batteries are reading 12.1. Monaco states that alternator and battery isolator need to be 200 amp not the current 140
amp they currently are at. Want to mention that all filters were changed before leaving and the alternator and battery isolator are also new. The shop is frustrated and want me to put in a 200 amp alternator and 200 amp battery isolator. They believe this is the problem. Monaco believes this might be the problem. Want to also mention I am plugged into 30 amp shore power and there is no DC although I have AC power. I need opinions. ..experience. ..help please. I am afraid that a new alternator/battery isolator won't fix the problem and after leaving shop the problem will happen again. This is not safe as losing power on I- 75S. Thank you in advance.
Class A
  • wolfe10's avatar
    wolfe10
    Explorer
    Nov 16, 2016
    Ivylog wrote:
    My educated guess is that at 12.1 V the fuel shutoff solenoid on the injection pump is not holding the fuel shut off lever all the way open reducing how much power the engine will make.


    Assume, yes assume that the OP means chassis batteries when wet-cell was mentioned with voltage of 13.8 VDC. The chassis batteries are the ones powering the fuel shutoff solenoid, not the house battery bank. So, voltage should not be an issue. Yes, the fuel solenoid is a known issue and there is an upgraded/stronger version from Cummins.
  • MrWizard's avatar
    MrWizard
    Moderator
    Nov 16, 2016
    We have a 95 safari dp with Cummins engine
    We have a 140 amp alternator and a 200 amp isolator
    The isolator has to be equal to out larger than alternator output
    Staring out with a low house batter bank they can take all the power the alternator will produce and you can burn out the diodes in the isolator
    What is the voltage at the engine battery with engine running
    (When you have the problem)

    It sounds like alternator over heat and shut down
    When this happens you start running directly from battery, not alternator
    When the engine battery gets low systems start shutting down
    Like the transmission controls and the fuel control valve for the injection pump
    A bad aka shorted battery engine or house can cause an overload on the alternator
    No dc power while plugged in is another clue, maybe blew a main fuse in the power circuits ? Inverter/converter not charging, bad battery blown fuse

    Track down your electrical and I think your power problem will be fixed
  • Ivylog's avatar
    Ivylog
    Explorer III
    Nov 16, 2016
    A bigger alternator will be a waste of money but getting 13+ V to the batteries will not be a waste of money. My educated guess is that at 12.1 V the fuel shutoff solenoid on the injection pump is not holding the fuel shut off lever all the way open reducing how much power the engine will make. Solve your 12V problems and hopefully your other problems will go away. I would run a string from the fuel solenoid to under the bed so the DW could pull on it if you loose power to make sure the lever is all the way open.

    When I had a 8.3 Cummins I carried one of these as they are a know problem item.
  • jdavidsmi's avatar
    jdavidsmi
    Explorer
    Nov 16, 2016
    I know you said the filters are new , but i would replace the fuel filter as a start. being a 96 a lot of crud could have accumulated it the tank. I would also check the fuel pressure.
    I could be way out in left field but from what i have read does not sound like electrical to me.
  • wolfe10's avatar
    wolfe10
    Explorer
    Nov 16, 2016
    Let's look at this statement: " The alternator is reading 13.8 amps. The battery line from battery isolator to wet cell battery is at 13. 8 amps. The battery line from battery isolator to 12V batteries are reading 12.1."

    You don't say whether you have a diode-based battery isolator or relay/solenoid-based isolator. If relay/solenoid-based isolator readings on alternator and battery side of the isolator will/should be the same. If diode-based isolator, the battery side will read about .7 VDC lower than the alternator side. And the diode-based isolator requires a "sense wire" to the chassis battery side of the isolator to allow the alternator to "make" an extra .7 VDC that is lost in the isolator.

    Given that you say that same 13.8 at alternator and at chassis battery I ASSUME you have a relay/solenoid-based isolator. If this is true, then the isolator is not functioning, as the house bank (assuming you don't have a bad battery) should be receiving the same voltage, not 12.1 which indicates a deeply discharged house bank.

    Agree with above-- no need for a higher-amp alternator. The factory advice is sage if you expect the alternator to not only keep up with normal battery needs, but to charge deeply discharged large house bank as well. Were it me, I would NOT spend $$ on this.

    I would also suggest getting with Steve at King Control to do some troubleshooting to verify that the King Control throttle (assume you have a King Control throttle as well as King Control cruise) is working properly.
  • Bill_Satellite's avatar
    Bill_Satellite
    Explorer II
    Nov 16, 2016
    A new alternator makes no sense. When the engine is running are you not seeing 13-14+ VDC at the battery? It seems like the engine is running which means the battery is still charged. You can't push more amps into a fully charged battery.
    I assume you mean none of your DC lights and such are working while parked but you should have full 12VDC power at the engine battery and the house battery bank. You should have charger on the house batteries as well keeping them full charged.
    I can't tell if the engine is keeping up power but the transmission is not doing it's job from your post. You said the engine would rev up but you weren't going anywhere. That would be the transmission.
  • JumboJet's avatar
    JumboJet
    Explorer
    Nov 16, 2016
    First - 13.8 Amps or 13.8 Volts. Unless you have an amp probe available I think you are talking volts.

    I hope you find someone that can tell you what is taking place. No 12V while plugged into shore power is a problem that needs corrected.
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Nov 16, 2016
    This is a 1996 coach and now, 20 years later, they are saying that the alternator is not large enough? I should add that I monitor my alternator output with my ScanGauge and it is usually at 14.4 volts and then tapers off as needed.

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