Blueline Bluewave drops to idle during jobs

Ardent

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Vincent Adams
I'm having issues with my machine, a Blueline Bluewave, suddenly dropping to idle while I'm in the middle of the job. This has been an ongoing issue for quite some time; however, the problem has become much worse this week. This machine has been well maintained, and works great except for this frustrating issue. I have the manual and have gone through the troubleshooting.

I have done many things to try and resolve the problem, including: changing the battery multiple times, upgraded to a larger battery, fixed/tightened ground cables, changed power cables all together, tested alternator (it tests fine; though I have a spare), changed the radiator, gone through most of the electrical, fixing/tightening connections, etc...

The best part is, the mechanics cannot find the problem (it never does this for them). They are unable to test for the problem unless it actually exhibits said problem.

Anytime I replace parts or tighten connections, it seems operate great for 1-day, then it goes back to the idle issue the following day. I suspect there are probably multiple things happening. I know that it is either an electrical or heat issue. I suspect heat, because I seem to have less trouble the lower I turn the heat, or on a nice, cool, windy day.

Currently, I suspect the Rostra-Vernatherm bypass valve under the waterbox... And also the possibility that the vacuum heater-core may be gummed up. But I also wonder about the engine's thermostat (which I have, but haven't changed) and temp sensor on the Kubota. I also wonder if it's the computer, or the electronic throttle control wigging out.

Does anyone have knowledge or experience with this problem on Bluewaves?
 
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Nomad74

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Is the circuit board mounted on top, above the engine? I've heard they have issues with overheating and cause them to run funky. Fixed by moving board to the side.
 
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Jim Martin

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Jim Martin
Just to start..there are a few things to look at...if the computer is inside the engine compartment then I would move it outside of the unit so it gets more air....My thermal wave was giving me all kinds of shut down problems and I moved mine outside of the engine compartment and it has not shut down in years...

second I would concentrate on the cooling fan...turn the key and the fan takes off..then a relay kicks in and then you start the machine...are you hearing the fan..is the relay kicking in...is the relay sticking...

if you have a lot of stuff around this machine and it is not breathing it may just be getting to hot...these machines need to breathe...move everything away from it and take a fan and point it into the machine and run it and see what happens...

Third..on your cat pump, you have a high and a low-pressure switch...one of them may be going out....unplug them one at a time and see what happens...

next..your oil pressure or water pressure switch on the engine could be going out...

you could have a high-level float that's acting up and sending a full tank signal to the machine and shutting it down....

this is where I would start looking...
 
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Justin Johnston
As others have said, where is the ECU mounted? This is the very first thing I would check.
Make sure the fan is coming on, and that there is airflow around the machine.
Are all of the connectors tight on the back of the speed control switch?
 
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Ardent

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Vincent Adams
The ECU is located inside the doghouse, in the upper left of the compartment. There is a good amount of space between it, the engine, and other components; however, I have considered the possibility that it may be the source of the troubles... Moving it outside the compartment is not something I had considered; but, perhaps I will try that.

The electrical panel is well separated from the engine, and I've gone through, tightening screws/connections periodically. The fan works great. I've replaced it before, and change the relay fairly often (This is usually the first thing I check when there's an issue). I also have a spare fan in my closet, as I expect it to go bad every few years.

It seems after I dismantled and reassembled the Rostra-Vernatherm bypass valve that the machine functioned almost flawless for a couple days. The second day it started to drop to idle once; but quickly revved back. The following day, I tightened another connection, opened up the blower heat-exchange and simply used compressed air to try and blow some gunk out. This gave me nearly a full day without incident.

Fast forward to yesterday, I had a commercial clean (roughly 5 hours). Immediately had trouble before I even got more than a dozen wand strokes in. It dropped to idle at least a half dozen times before I could even finish one big office. I turned the heat down to probably less than half... And I finished the job without incident after that. This leads me to think that it is either the bypass valve, or the blower heat-exchange, but, I am guessing.

Here's another issue, I'm having: Even with a brand new, beefier battery, I'm still having to occasionally jump it to start. Battery reads 12.93 volts, and it still wants more voltage to start. I'm finding it wants 13.1 or more volts to start, which seems high. The starter is only a few months old. The connections seem solid, so I'm not sure why it would need extra juice.
 
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Ardent

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Vincent Adams
As others have said, where is the ECU mounted? This is the very first thing I would check.
Make sure the fan is coming on, and that there is airflow around the machine.
Are all of the connectors tight on the back of the speed control switch?
I actually replaced the speed control switch a few month ago. I'll try mounting the ECU outside see if that helps. The machine seems fine if I turn the temp control down significantly.
 
Joined
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Chandler Arizona
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Justin Johnston
As others have said, where is the ECU mounted? This is the very first thing I would check.
Make sure the fan is coming on, and that there is airflow around the machine.
Are all of the connectors tight on the back of the speed control switch?
I actually replaced the speed control switch a few month ago. I'll try mounting the ECU outside see if that helps. The machine seems fine if I turn the temp control down significantly.
Sorry, I thought this was a Thermalwave, not a Bluewave. The Bluewave does not have an ECU, just a throttle actuator. So I would look at the fan, airflow, grounds, and connectors on the switch first.
 

Ardent

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Vincent Adams
An UPDATE:

I replaced the thermal bypass valve over a week ago. I've been running the BlueWave at full heat, and it has not dropped to idle once, since replacing the valve. It seems like this was the culprit.

Basically, the valve was stuck, which caused the hot water to keep getting hotter, rather than mixing with the cool, fresh water entering the water box (water is recirculated, rather than dumped as waste). At a certain point, the Kubota's coolant is not loosing sufficient heat via the heat exchangers, so the kubota computer reduces the throttle to idle until it cools off sufficiently, at which point it revs back up to operating speed... at least this is my working theory.

20200628_180257.jpg
 

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