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Nomad Mike · 12-05-2021, 05:40 PM

So I went to do my monthly start of the coach to run the engine and generator and the generator would not crank over, but I hear a relay type clicking sound. It sounds like its coming from the front electrical panel containing the house disconnect solenoid, fuses, relays and after market Trik-L-Start, etc. I hear this clicking on both priming side of the switch and starting. Seems if it is the starter solenoid I wouldn't hear it when priming?

The model is HDKAJ Spec H. There are three start switch locations, house monitor panel, dash and directly on the Onan. The house monitor panel is simultaneously not lighting the status light for priming or starting and the house light above the panel is affected with a very slight dimming - so slight it is almost unnoticeable.

When I start using the priming or start I hear the rapid clicking sound of a relay or solenoid trying to work. The red light on the gen start switch and the green light on the dash blink rapidly. No codes, just rapid on/off.

I'm wondering if there is a relay associated with the starting switch and that it is also affecting the house panel switch which has no lights?

I climbed under and listened and felt the starter housing while a friend depressed the switch. I could not tell if it was the starter solenoid or not. The clicking is loud and direction not discernable. I could slightly feel it at the housing, but still sounds louder than what I was feeling at the starter.

How can I check to see if the solenoid is getting 12v without disassembly? Batteries are new and it's connected to 50A service. I've tried with and without the engine running.

I've been looking at manuals and diagrams for several hours now, hoping someone can lead me to the right area to look.

YC1 · 12-05-2021, 05:55 PM

How long are you holding the button down for?

Is it cold outside.

It can take quite a while for the starter to engage when its cold as the glow plugs heat things up.

FIRE UP · 12-05-2021, 08:55 PM

Well,
One of the first things we need to know is, what is the ambient temp while you're trying to start the gen? You see, if you've not experienced a cold start situation with that gen, it's possible that you are not holding the start button long enough, for the temperature conditions you're in. You see, if you look in the Onan service and or owners manual for that 7.5, you will find a chart that details the start sequence for cold start operations.

If you know all this, and you're aware of the time sequence starting, then forget what I'm saying here. If you don't know this, then here's the short version. The temp sensor that's very close to the thermostat, sends that little Kubota 3 cyl 14HP diesel engine's ECM a signal that it's too cold for a rapid start if, it's below certain temps outside and the coolant.

So, the ECM dictates what needs to be satisfied prior to starting. That little engine has GLOW PLUGS, where as, the main engines do not. If the ambient temp is low enough, the starter is not allowed to engage, until the glow plugs have been on for a given amount of time. If, the temp is even lower, the glow plugs need to be on for an even longer time frame. And finally, if the outside temp is really low, those glow plugs may need to be ON for as much as 20 or more seconds, before the ECM allows the starter to engage.

I used to know all the degrees of temp, and how long each time frame was, prior to the engine cranking but, that's been a while. It's all in there, in the manuals.

Now, if you don't have this "cold start" set of conditions, well, then you've got other problems.
Scott

radar · 12-05-2021, 10:14 PM

It’s cold. Hold the button down , then hold it some more, then after you are tired of waiting and convinced that there is a problem.....hold it some more. If it doesn’t start to crank after a few minutes then there may be a problem. But if it’s cold you’ll be holding for a long time before it cranks. At least that’s the way it was with ours.

Cheers.

Nomad Mike · 12-05-2021, 10:34 PM

Our temperatures are unseasonably warm, mid 40's at night to low 60's in the daytime. I've had no problems starting it in the low 30's before.

Would being too cold cause the continuous clicking and flashing of the LED while pressed, and for both starting and priming? Same sound and light with the rocker either way.

Tomorrow I'll see if I can try and get video/audio.

radar · 12-05-2021, 10:39 PM

Yes. That is normal. The clicking and priming is normal in both positions.

And yes. That’s what it does in the cold.

YC1 · 12-06-2021, 03:31 AM

Here is the startup sequence with pre-heat times.

Bad glow plugs can create issues of their own but it should begin to turn over after the specified periods.

indiana journey · 12-06-2021, 07:39 AM

How much fuel is in your tank? 1/4 or more?
When was the last time that you changed the fuel filter on the generator?
Just a couple of simple things that sometimes give us headaches.
Good Luck,
Indiana Journey

Nomad Mike · 12-06-2021, 12:58 PM

Quote:

Originally Posted by radar

Yes. That is normal. The clicking and priming is normal in both positions.

And yes. That’s what it does in the cold.

Thanks everyone, that did work and started at about 30-45 seconds.

FIRE UP · 12-07-2021, 09:14 PM

Quote:

Originally Posted by Nomad Mike

Thanks everyone, that did work and started at about 30-45 seconds.

As you can see in that linked PDF, the chart states a maximum of 15 seconds of holding down the start switch, not MINUTES. I think the longest I've held my start switch down before it was allowed to crank that little diesel over was about 7-8 seconds or so.
Scott