Skip to main content ↑ ↓
Topic: Genset Dies ? Any Ideas? (Read 594 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Genset Dies ? Any Ideas?

Yahoo Message Number: 80872
My HDKAK 8kw Onan has started dying when the ignition key is turned on (10% of the time) or after the engine is started (90% of the time). It make take 10 seconds or 5 minutes, but it always dies. I systematically removed and then replaced the Xantrex RC7-GS remote, the Silverleaf engine monitor, and the rocker start switch which eliminated all three when the problem continued to happen. When I disconnect the cable at the genset, the generator no longer fails over any time period so the genset is eliminated.
Here is where it gets heavy. In tracing the circuits, the generator start and stop signals (wires 159 red and 158 brown respectively are normally high (12 volts). When any one of the three components, inverter, Silverleaf or manual rocker switch connect wire 157 (ground) to wire 159 or wire 158 the generator starts or stops (again, respectively). The only reasonable conclusion then is that when the ignition is turned on, there is a gremlin conditioning that 158 wire with a false ground.
To test the theory, I monitored wire 158 (genset stop) with a digital volt meter. With the genset off, there was 12 volts nominal on the wire. When I started the generator, the voltage on 158 dropped to 9.5 volts and stayed there, probably because it is a sensing circuit. Then I turned on the ignition key, but the generator continued to run. It only dies 10% of the time with the key. Then I started the engine. Less than a minute later there was a negative spike (dropped to 4.5 volts) for less than half a second, and the generator died.
Does anyone have a clue where that split second spike might be coming from? I doubt a short because it come fast and predictablely, not like a bad ground or frame short would generally present. This just started in the last year. It never happened before that so something has started to fail.

Stuart Thornton, 2005 Allure, #31217

Re: [Country-Coach-Owners] Genset Dies – Any Ideas?

Reply #1 –
Yahoo Message Number: 80893
First thing I'd do is disconnect the remote wiring harness coming out of the generator & see if the problem goes away or continues. If it continues then it's a generator issue or low battery. If it stops then it's in the remote wiring, either switches or inverter. Unplug the generator remote leads from the inverter after/before reattaching the remote plug at the gen and see if that corrects the issue, if not then on to the switches. Do one thing at a time and you'll figure it out.

Jim

From:stuart3488 Sent: Thursday, July 12, 2012 2:14 PM To:Country-Coach-Owners@yahoogroups.com Subject: [Country-Coach-Owners] Genset Dies - Any Ideas?

My HDKAK 8kw Onan has started dying when the ignition key is turned on (10% of the time) or after the engine is started (90% of the time). It make take 10 seconds or 5 minutes, but it always dies. I systematically removed and then replaced the Xantrex RC7-GS remote, the Silverleaf engine monitor, and the rocker start switch which eliminated all three when the problem continued to happen. When I disconnect the cable at the genset, the generator no longer fails over any time period so the genset is eliminated.
Here is where it gets heavy. In tracing the circuits, the generator start and stop signals (wires 159 red and 158 brown respectively are normally high (12 volts). When any one of the three components, inverter, Silverleaf or manual rocker switch connect wire 157 (ground) to wire 159 or wire 158 the generator starts or stops (again, respectively). The only reasonable conclusion then is that when the ignition is turned on, there is a gremlin conditioning that 158 wire with a false ground.
To test the theory, I monitored wire 158 (genset stop) with a digital volt meter. With the genset off, there was 12 volts nominal on the wire. When I started the generator, the voltage on 158 dropped to 9.5 volts and stayed there, probably because it is a sensing circuit. Then I turned on the ignition key, but the generator continued to run. It only dies 10% of the time with the key. Then I started the engine. Less than a minute later there was a negative spike (dropped to 4.5 volts) for less than half a second, and the generator died.
Does anyone have a clue where that split second spike might be coming from? I doubt a short because it come fast and predictablely, not like a bad ground or frame short would generally present. This just started in the last year. It never happened before that so something has started to fail.

Stuart Thornton, 2005 Allure, #31217
 

Re: Genset Dies ? Any Ideas?

Reply #2 –
Yahoo Message Number: 80901
Okay, it looks like I am drilling down on the problem. After cutting and mending several signal paths in the coach that control the stop circuit for the generator, I was stuck as to how to proceed. I had eliminated the SilverLeaf VMS-200 engine monitor earlier because when I unplugged it, the problem was still there. But now I was becoming suspicious of it again.
I decided to call SilverLeaf in Albany, Oregon to see if they had anything to offer, and low and behold, they directed me to the bathroom wall behind the circuit breaker panel and systems controls (tank monitors, HVAC, etc.). Somewhere there should be a black box that is the hidden element for the SilverLeaf display. It turned out to be under the floor of the cabinet under the sink. Apparently this generator dying is a known problem and the box needs a software update.
What was fooling me during the hunt was the start and stop commands made from the SilverLeaf display on the dash are sent to the black box, which in turn communicates the commands to the Xantrex RC7-RS remote, and the remote talks to the inverter which sends the appropriate signal to the generator. That is why I was unable to trace a stop signal wire directly to the SilverLeaf display.
Thanks you Mikee, cmarshall and Jim for the thoughts. This one was a duzzie.