Doesn't always crank over when key is turned.

[draboo]

This is a still a problem. I have cleaned every single connection on the batteries. I have not cleaned off the connection to the starter. Are there any other connections, like relay connections, that I should look at? Could this be a bad relay? I thought I had it licked a few months back, but it did it again when I had to get propane.

Thanks,eh?

Brad

2002 Holiday Rambler Neptune PDQ ISB 275 hp Cummins engine.

[Mr_D]

My ISX will do that at times even with 3700 CCA's of battery. Cure on mine is to replace the starter with a gear driven Denso.
On the '02 DSDP ISC 350 we started having problems starting, the cure for it was also replacing the starter since it had a bad pole.

[clifford j]

DraBoo, explain what "it doesn't always turn over" is there a click, no noise at all, dose it crank slowly. Dose it only happen with cold engine. What other symptoms have you experienced.

CLIFFORD

[Smitty77]

If it is not turning over, or clicking, then your obvious next steps would be to clean the connections at the starter. Also, some RV's, have a mini busbar that is in the loop. So look in and around the engine bay, or even trace a wires back from the starter if you can. A Country Coach owner finally tracked his down to being this sub busbar connector needing to be loosened and connections cleaned.

And sometimes, it can be a bad ignition key.

Happy hunting, and please share what you find out - as it could help others in the future.

Best,
Smitty

[draboo]

Thanks for the suggestions. When it does spin over, it spins very fast and starts instantly.

[Rook]

The most likely candidate for causing your problem is the "Starter Relay", (different from the Starter Solenoid), they fail regularly. This is easy to diagnose if you have a DVM and know how to use it. Rook

[jacwjames]

I had the same thing happen to me over a period of months. Turn the key and nothing, no power to dash etc. Turn the key off and back on and it would start.

Finally when I was getting ready to go on a trip I'd turn the key on and off several times still nothing.

First thing I checked was if I was getting power past the chassis cut off switch. I was not so I took the switch off and bolted the 2 leads together and the power was restored. I tested the cut off switch and it was bad, I could not get it to work, it was a sealed unit so not really sure what happened. Ordered a new one (and a spare since the house also uses one) and installed and all is good.

[ahicks]

Erratic problems, those that can be difficult to replicate predictably, are RARELY easy to diagnose.....

"The most likely candidate for causing your problem is the "Starter Relay", (different from the Starter Solenoid), they fail regularly. This is easy to diagnose if you have a DVM and know how to use it"

[clifford j]

The start circuit has several components, two were mentioned , the ignition switch, the starter solenoid ,oh and the starter relay. Another component is the neutral safety switch on the transmission. Identifying the culprit is not an easy task. If the trouble is cleared meters won't find it. I've hung a tiny test light in various locations in the start circuit to find how far the power went. I've had customers come in with this exact trouble. I tell them it's like your tv stops working and when the repair guy shows up it starts working , he now says I can't fix something that's working. One solution is to start throwing parts on in hopes to solve the issue. That's not the right thing to do, unless your rich. :>)

CLIFFORD

[Rook]

It's usually understood that you cannot troubleshoot a working system.....you have to wait till it's not working to troubleshoot! Rook

[ronandsue74]

Brad,
My symptom like yours turned out to be the starter solenoid.
I was able to just pull the solenoid off the starter, once I got it apart it was very obvious that it was not making good contact. I cleaned up both contact surfaces and all has been well for the last two years.
An easy fix once found.
RJ 2005 CC Inspire #51264

[Unplanned Tourist]

I had a problem like this and ran a small #14 wire from the big cable at the starter up to inside the cab. Then I hooked a light to the wire and grounded the other light wire. When the starter was engaged, the light would come on. This tells you the starter is getting full power. If the light doesn't come on, it is a problem back towards the starting batteries. This may save you the expense of just randomly changing parts until it is cured. Good luck.

[Toribk]

Brad,

I'm not sure on your Neptune, but some coach/chassis manufacturers install a starter relief relay (coil) usually mounted on the frame rail close to the starter.

Later models have the relay and solenoid mounted on top of the starter motor as one unit.

This frame rail mounted relay has been the cause of intermittent starting problems because it is subject to exposure and corrosion.

From your starter, follow your main power cable (red) and see if it initially terminates at a relief relay before continuing on to your chassis battery. If so, disconnect your negative battery terminal on the chassis battery and remove and clean all four terminal connections with fine Emory cloth. Apply a bit of terminal anti-corrosion spray and then reassemble the connections.

Why your at it, there is usually a large bolt on 150 amp (or more) fuse mounted adjacent to the relay, so clean those connections as well.

Do the same for all the connections on the starter too.

I'll follow up with a couple of photos that show the relay/fuse and a close-up of a new one.

[Toribk]

Here are two photos. One shows the new relay and the other, thanks to another contributor on the forum, shows where it is mounted on the frame rail.

If applicable to your coach, I hope this helps.

Let us know.....thanks.