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-   -   Onan 10HDKCA Overheating (https://www.irv2.com/forums/f84/onan-10hdkca-overheating-534084.html)

Corc 04-28-2021 06:59 PM

The generator already has a temp sensor on it, feeding information to the control. Seems you could tap into it and add a standard resistance gage, if you knew the sensor value. Otherwise you could tee in an additional sensor pretty easy.

The Onan techs can read actual coolant temp with electronic service tool, inPower. Control uses temp to determine things like glow plug burn time. Do not know anyway for customer to access or display control data.

HarryStone 04-30-2021 04:26 PM

Quote:

Originally Posted by Corc (Post 5730780)
The generator already has a temp sensor on it, feeding information to the control. Seems you could tap into it and add a standard resistance gage, if you knew the sensor value. Otherwise you could tee in an additional sensor pretty easy.

The Onan techs can read actual coolant temp with electronic service tool, inPower. Control uses temp to determine things like glow plug burn time. Do not know anyway for customer to access or display control data.

It's likely the temp sensor is a preset switch. Closed until it hits a preset temp, then it opens. I doubt the gen set would need a sophisticated sensor like cars have.

roketenginer 05-14-2021 08:20 PM

Thought I'd give a quick update on this deal.

So I bought the pressure cap, thermostat (71 degree C), and temperature sensor. I also installed gauges for the generator at the drivers station (water temp, oil pressure, chassis battery voltage) these gauges only work when the generator is on. Pretty slick set up if you ask me. The temp and oil sensors are electric on this gauge set-up so its really easy to wire up.

So after refilling coolant with Prestone, burping the air I let the engine run for about 2 hours no issues. I used my Flir infrared camera to see where the heat was soaking into the radiator. The incoming side of the radiator was ~150-160 and exiting was ~100-110. So the radiator is working, the cowling is pulling a vacuum and drawing air through the radiator.

The engine then cut out after 4 hours. Throwing a 3-6 code. So I let the engine cool, I checked the oil level and it was maybe 2 mm above the full line so I siphoned some out. Interesting note, before I siphoned the oil my gauge was reading ~30PSI... I thought this was a manufacturing defect. After I took out some oil my pressure went up to ~42PSI. Coincidence? I think not.

I think the random shut down 3-6 code can also be triggered by fuel, or other factors... Like crankcase pressure. As it turns out oil level in diesel engines can create wild amounts of crankcase pressure. I think this might have been my issue.

If y'all want a write up on my gauge installation I can create a new thread and do it there.... SUPER straight forward if you know which side of the wrench is up.

nbluesky 05-15-2021 09:56 AM

Thanks for posting a follow up! I'm curious if you run it now for extended time does it indeed stay running? 30 psi does not seem low enough to trigger a shutdown but I'm not sure what the threshold would be.

Yes of course would love to see some pics of the new setup!

roketenginer 05-15-2021 01:55 PM

Ok, so it ran for about 1.5 hrs and .4 both times before throwing a 3-6 code twice. I bled the injectors, checked the fuel rail; clean. I'm now going to order a fuel pump. My guess is that this pump gets lazy when it gets warm. My understanding of electronics says that's a reasonable assumption. So now on the chopping block is the fuel pump. Looking at the old records the previous 2 owners didn't replace much so this may be an original part. When you hold down the stop switch you hear (and can feel) the pump pumping.

If the new pump doesn't work I'll replace the rubber fuel lines, and if that doesn't work I'll assume at that point the computer might be tripping out.

The fuel filter is new (~20 hrs). I'm considering putting one of those FleetGuard cannister filters at the tank just for good measure... But maybe after I can get this thing running for more than 2 hrs at a time.

Ok, I'll get on that post for yall about the gauges!!

roketenginer 05-15-2021 04:10 PM

Quote:

Originally Posted by nbluesky (Post 5752214)
Thanks for posting a follow up! I'm curious if you run it now for extended time does it indeed stay running? 30 psi does not seem low enough to trigger a shutdown but I'm not sure what the threshold would be.

Yes of course would love to see some pics of the new setup!

https://www.irv2.com/forums/f258/add...or-536969.html

nbluesky 05-15-2021 08:25 PM

Quote:

Originally Posted by roketenginer (Post 5752407)
I'm now going to order a fuel pump. My guess is that this pump gets lazy when it gets warm. My understanding of electronics says that's a reasonable assumption.


Hmm. Do you have a way of checking fuel pressure and watching to see if it drops as the pump gets warm? Seems unlikely to me that that would be the problem. EDIT: After reading several post of folks saying a new fuel pump fixed their problem I understand your thinking.

Also have you confirmed that it is not shutting down due to coolant temp? I assume so now that you have the new gauges installed.

Found this comment on another post, worth checking out:

"... after chasing stuff around like the fuel filter,etc, , I found it to be a bad 12v battery power connection to the genset"

I always try to troubleshoot and test things to find the source of the problem before throwing parts at it. I have had better luck in the past doing that. Sometimes it can be really frustrating finding the problem but in the end it feels really good knowing you diagnosed the issue and fixed the source of the problem with one fix. Just my way of doing things but to each their own!

roketenginer 05-22-2021 09:01 PM

So I replaced the fuel pump and I'm not sure if I made the issue better or worse. It's still shutting down and throwing a 36 code.

I primed the engine with the rocker switch as the manual says for about 1 minute and then again for another minute. Started up and ran for ~0.7 hours.

I tried to restart and it wouldn't run longer than 1 second. So I'd try to reprime and I couldn't hear the fuel pump pumping... It is hooked up because it did work the first two times initially.

At this point I'm thinking maybe the computer is bad. I'm going to look alittle closer at the fuel shutoff governor, bleed the lines at the injectors, and recheck the fuel lines for cracks where it might be sucking water.... I think I'm also going to blow compressed air through the fuel line that goes to the tank.

More on this later...

THenne1713 05-22-2021 10:40 PM

Is there a fuel solenoid, or solenoid that operates a manual valve, or something that a loose wire/ bad coil would shut down fuel? Never seen this engine, nor studied their manuals... but know those control boards are $$$ and loose wires/ bad solenoids are cheap to fix. Corroded connections or rodent damage are very common w/ RVs

shootist 05-22-2021 11:06 PM

To reset the board you have to disconnect the 12v cables coming in the back of the gen. Mine would crank and not start, then would not even crank nor turn on the fuel pump. I had shut it down under load one time that caused it. Disconnection of 12v to the gen fixed it. It was throwing governor codes.

Mile Marker 42 05-22-2021 11:13 PM

Crazy question, but have you disconnected power to the generator underneath for 30 mins and wire brushed any corrosion from the cable terminal ends and mounting studs? I had an issue recently with my 7500QD and this actually fixed my issue. An aviation mechanic suggested this to me as he said this is how they clear codes on planes.

roketenginer 05-23-2021 09:20 AM

Quote:

Originally Posted by THenne1713 (Post 5762003)
Is there a fuel solenoid, or solenoid that operates a manual valve, or something that a loose wire/ bad coil would shut down fuel? Never seen this engine, nor studied their manuals... but know those control boards are $$$ and loose wires/ bad solenoids are cheap to fix. Corroded connections or rodent damage are very common w/ RVs

I'm going to check the solenoid next; I found the service manual thanks to the files page here.... LIFE SAVER.

I'm also going to look a little deeper into the injection pump to ensure nothing is jammed.

I'm going to do the 12v power off for an hour to see if this remedies anything to reset the computer; I'm also going to check for frayed wires.

roketenginer 05-23-2021 09:21 AM

Quote:

Originally Posted by Mile Marker 42 (Post 5762023)
Crazy question, but have you disconnected power to the generator underneath for 30 mins and wire brushed any corrosion from the cable terminal ends and mounting studs? I had an issue recently with my 7500QD and this actually fixed my issue. An aviation mechanic suggested this to me as he said this is how they clear codes on planes.

I did that when I cleaned the terminals on the back of the gen... I'm going to check for continuity here next.

roketenginer 05-23-2021 12:47 PM

Ok, so I went through the service manual and checked all of the applicable areas. I checked the fuel fittings, I checked for cracks, etc. All good.

I when through and tested fuel flow through the filter. Good again. The service manual wants 8oz in <1 minute. Mine did 8oz in ~20 seconds.

I removed the governor actuator and tested it for the 2-4ohms AND I put 12v to it and the plunger retracted. So thats good.

The last thing on the list is control board replacement followed by 'service the engine'. My best guess is, when this engine runs it runs extremely well. I'm no stranger to Kubota engines and have a tractor, skid steer, and UTV all kubota, all ~20 years old.

My personal thought is the control board. I've read where some handy guy wired a relay to bypass the fuel pump control to just turn the fuel pump on whenever the engine is running. I may go that route in the interm if I can't find a control board (with a warranty...).

I'm grasping at straws here. Fuel filter, fuel pump, air cleaner, oil filter, oil level are all good. Its not overheating and it has nominal oil pressure.

If anyone doesn't have any ideas... lol


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