Intermittent Starting Failure

[BT-III]

Hi everyone,

I have experienced for quite some time now an intermittent starting failure problem with my Dynasty 2003 Cummins ISL400.

I turn the key, nothing happens. On a second, third or forth attempt the engine crank like a brand new. This situation can happen once or twice during a trip that involves 50 to 75 engine starts.

In 2005, Monaco refused to investigate the problem when I was at their Wildwood Service facility in Fl. They directed me to Cummins in Ocala where they were able to replicate (at least that’s what they said) the problem. Their verdict was a “flying short”. Corrective action: replace the starter. On my way back home the same problem occurred again.

Since, I have replaced again the starter and subsequently the starter solenoid (located in the engine compartment) without any results. I opened-up the solenoid and found nothing wrong with it.

We are now in 2011 and I still have this intermittent problem. The good part of this sad story is that the engine finally starts after 2, 3 or 4 attempts. But I am haunted by the idea that one day it will not start period. Will that occur at a Flying-J fuel-up bay, a rest area in the middle of nowhere, at the Custom Border? I am terrified by the vision of my coach being towed.

Any help would be appreciated. Thanks

Louis L & Louise Charbonneau

[86 Cavalcade]

Louis, On my 2001 Diplomat I have a solenoid on my starter, I think that is the one you are talking about. I also have another solenoid "this solenoid is about 2" in diameter and about 3" tall, it has a total of 4 wires connected to it. It has 2 #8 AWG wires and a white #14 that goes to ground and a #14 that comes from the ignition switch". This solenoid is only energized when you have the ignition key in the start position. I could never figure out what this solenoid did until I had my wife try to start my coach while I had a VOM hooked to this solenoid. These wire sizes I did not measure but this is my estimate of their size. This solenoid supplies the power to my actual starter solenoid. I would find this solenoid and replace it or at least take it apart and inspect it. My ignition switch is bad and the engine always cranks but when I let the switch spring back to the run position I have to be careful and not hold on to the key or it will stop just like I had turned the key to the off position. I would find this start solenoid " I am not talking about your actual starter solenoid here" and look at it. If it is OK then I would replace the ignition switch. My start solenoid is located in the rear curb side compartment about 3 feet from the starter. Your start solenoid will be located back close to your engine. George R. 2001 Diplomat

[Dunner]

What about a neutral or park switch. When it doesn't start, shift it out and back into park, or push it more towards park or if it normally will start in neutral, try it there. My dad had a Mustang and would sometimes call me complaining of it not starting. Turned out the floor shifter was worn out and not letting the park switch engage.

[Dr4Film]

Have you looked at the ignition switch as a possible cause?

Dr4Film ----- Richard.

[rpasetto]

I didn't know about the second relay in the circuit as 86 Cavalcade noted. Dunner , There's no mechanical "park" switch on the Allison trans, but there might be yet another relay, controlled perhaps by the TCU; also could it be that the start circuit is interrupted by the parking brake?

I've thought about the proliferation of mechanical ("continuous duty") relays. There's a wiring diagram for the 03 Dynasty online at Monaco's website...
http://www.monacocoach.com/StaticFil...nasty03_WD.pdf

I downloaded it recently... haven't begun to pour through it yet. It may be of help.

[Dunner]

Something has to tell it not to start in gear. Be it a magnetic or mechanical switch, something has to tell the ECU or whatever that it is not in neutral or park.

[ga traveler]

Quote:

Originally Posted by 86 Cavalcade Louis, On my 2001 Diplomat I have a solenoid on my starter, I think that is the one you are talking about. I also have another solenoid "this solenoid is about 2" in diameter and about 3" tall, it has a total of 4 wires connected to it. It has 2 #8 AWG wires and a white #14 that goes to ground and a #14 that comes from the ignition switch". This solenoid is only energized when you have the ignition key in the start position. I could never figure out what this solenoid did until I had my wife try to start my coach while I had a VOM hooked to this solenoid. These wire sizes I did not measure but this is my estimate of their size. This solenoid supplies the power to my actual starter solenoid. I would find this solenoid and replace it or at least take it apart and inspect it. My ignition switch is bad and the engine always cranks but when I let the switch spring back to the run position I have to be careful and not hold on to the key or it will stop just like I had turned the key to the off position. I would find this start solenoid " I am not talking about your actual starter solenoid here" and look at it. If it is OK then I would replace the ignition switch. My start solenoid is located in the rear curb side compartment about 3 feet from the starter. Your start solenoid will be located back close to your engine. George R. 2001 Diplomat

i think your problem is the solenoid. Most of the tech's called this the power up solenoid. When you turn your switch on, it powered up this solenoid and sent power to the dash, fuel valve, etc. find this solenoid and the next time this happens, leave the switch on, go to the solenoid check for power on the small power up wire. then check for voltage on both in and out main wires.

[Airtool]

There are 5 points that are possible cause. Neutral Safety Sw., Key Switch, Castle Relay, Starter Solenoid and Started Motor.
Neutral Safety Switch - Not adjusted properly,loose or defective.
Key Switch-bad contacts or milted terminals.
Castle Relay-Corroded connections or failing contact and coil.
Starter Solenoid - Contractor sticking or burned out Contacts.
Starter - Warren brushes and armature.

All can be intermittent before failing or in the case of the Neutral Safety SW. going out of adjustment to where it no longer works.

Dick.

[rpasetto]

Quote:

Originally Posted by Dunner Something has to tell it not to start in gear. Be it a magnetic or mechanical switch, something has to tell the ECU or whatever that it is not in neutral or park.

Right! That's why I posted the link to the wiring diagram.

[rpasetto]

Quote:

Originally Posted by Airtool There are 5 points that are possible cause. Neutral Safety Sw., Key Switch, Castle Relay, Starter Solenoid and Started Motor. Neutral Safety Switch - Not adjusted properly,loose or defective. Key Switch-bad contacts or milted terminals. Castle Relay-Corroded connections or failing contact and coil. Starter Solenoid - Contractor sticking or burned out Contacts. Starter - Warren brushes and armature. All can be intermittent before failing or in the case of the Neutral Safety SW. going out of adjustment to where it no longer works. Dick.

Nice list... what's the "castle relay"?

[Airtool]

Fallow up ! If you have a road service provider, and it does not start; have the service person just jump the 12 volt supply for the starter from the Castle Relay terminals to the 12 volt connection on the Starter.You mentioned that this has been replaced so it should work doing this little trick.
This will save you having to get it towed.
Remember to have the key in the run position when trying this and ALWAYS check to see if the alternator voltage come up to its proper level!
The ignition key circuit energizes the alternator in the starting position.
Hope this helps reduce the fear of getting towed.

The Road service should always have jumper cables only wire that will Handel the current needed !!!

Dick.

[Airtool]

Rick, the castle relay is what the key energizes, this in turn supplies the required voltage and current to the starter. Generally located very close to the starter and in the wiring running to the starter.
Hope this answers your question. Dick.

[86 Cavalcade]

Louis, Download the wiring prints using the link above and look at page 81 and you can see that you do have a neutral safety relay and you have this intermittent relay that has nothing to do with powering the chassis or anything else. It's only purpose is to supply the 12 volt power to your starter solenoid when the key is in the start position. Look at the print and you can see how the start system works. Good luck, George R. 2001 Diplomat

[86 Cavalcade]

Louis, This intermittent solenoid is located on your rear run plate. George