$12,000 paperweight

[Richpatty]

As we were preparing to leave on our most recent trip, we started up the generator to run the AC (and give it some exercise) and after starting and running for a about 5 minutes, it quit…. I opened the hood to take a look and it was flashing a service code of 2, then 4 blinks. I reset the code and ran the generator again and it quit in the same way. After not finding the 2-4 this combination, I called Cummins and was told it was a coolant temperature sensor.

The part appears to only be about $50, but it is located in the back of the motor (although on top), but since the Ventana does not have a generator slide, it makes it almost impossible to get at.. I am not sure I can get the pan cover off of the top to get in there.

I called a few RV places (including NIRVC and Freightliner Gafney) and neither would touch it…and recommended going to a Cummins center. I called the Cummins in Charlotte and they said it they may have to drop the generator to get at it ( that does not surprise me) an that they would have to call me back with and estimate. Still waiting nearly 24 hours later…. Anyway, I am glad I have my solar and lithiums as I can run the front AC from there for now.

Anyway, does anyone have any thoughts? Has anyone taken the cover off, especially if you do not have a generator slide?

I am sure this will cost a ton of money to have done for a stupid $50 part so I begin to wonder why Newmar does not put generator slides on all their models. It is not a luxury feature but necessary for work to be done.

 

[Neal]

The not fun part about RVing. Ugh! Sorry to hear this!

Reach out to @Chuggs as he had to have an issue serviced with his GEN and he may be able to give you ideas.

What about Newmar? I know it's a trek for you, a 2 day trip but maybe it could be opportunity to get this fixed and new up the coach for anything else you've had in mind?

 

[Neal]

Out of curiosity @Richpatty when is the last time you changed the oil, filter, air filter, fuel filter, etc.? Those things you can do and if it was me I'd probably start doing some of those things first and see what the result is. I had an issue one time which was simply oil overfilled and it caused issues. Drained a "cup" and it solved my problem. It can be finicky.

 

[Richpatty]

I have been pretty good at doing the basic maintenance you mentioned…. And did change the coolant back in September, but have 10+ hours of use since then.
Thanks for the ideas.

 

[Neemer]

I had to have extensive work done on my previous rig’s 7.5kw Onan. People who work on these things are well versed on getting them out of rigs that don’t have generator slides. Should be a couple of hours labor at most.

In my case, they removed the middle piece of the front cap in front of the generator, unbolted the genset, then rolled it out on a trolley.

 

[Richpatty]

I had to have extensive work done on my previous rig’s 7.5kw Onan. People who work on these things are well versed on getting them out of rigs that don’t have generator slides. Should be a couple of hours labor at most.

In my case, they removed the middle piece of the front cap in front of the generator, unbolted the genset, then rolled it out on a trolley.

Yea….I saw a video on YouTube where someone did exactly that. But I do not have the jack to lower it (nor enough knowledge to pull it off).

 

[Voyageurs]

As we were preparing to leave on our most recent trip, we started up the generator to run the AC (and give it some exercise) and after starting and running for a about 5 minutes, it quit…. I opened the hood to take a look and it was flashing a service code of 2, then 4 blinks. I reset the code and ran the generator again and it quit in the same way. After not finding the 2-4 this combination, I called Cummins and was told it was a coolant temperature sensor.

The part appears to only be about $50, but it is located in the back of the motor (although on top), but since the Ventana does not have a generator slide, it makes it almost impossible to get at.. I am not sure I can get the pan cover off of the top to get in there.

I called a few RV places (including NIRVC and Freightliner Gafney) and neither would touch it…and recommended going to a Cummins center. I called the Cummins in Charlotte and they said it they may have to drop the generator to get at it ( that does not surprise me) an that they would have to call me back with and estimate. Still waiting nearly 24 hours later…. Anyway, I am glad I have my solar and lithiums as I can run the front AC from there for now.

Anyway, does anyone have any thoughts? Has anyone taken the cover off, especially if you do not have a generator slide?

I am sure this will cost a ton of money to have done for a stupid $50 part so I begin to wonder why Newmar does not put generator slides on all their models. It is not a luxury feature but necessary for work to be done.

Hi Rich. Sorry to hear of your problems with the generator. We had the exact same fault and the exact same situation with not having a generator slide.

So yes. The culprit is the sensor. I’ll give you a little info on the circuit logic but for the fix (or at least ours) I would rather give you a call as it’s a little lengthy and I suck at writing this stuff.

Here’s the circuit logic. Upon initial start the logic board ignores the sensor voltage for the first minute. Then from minute 1 to minute 5 it looks for a change in the sensor voltage. It doesn’t care what it is, just that there is a change. That tells the board the sensor is working. If it doesn’t see a change it shuts off the generator at exactly 5 minutes.

We found a way to bypass the signal (Or more specifically to trick it) but you will still need to access the wire coming from the sensor. We couldn’t get to the sensor itself without removing the generator. We were able to access the wire by taking the front cap off the Motorhome. Not something for the faint of heart. Especially for two fifty something year olds (that was 10 years ago) But we didn’t have to pull the generator. There is more to this than it sounds and I would be happy to explain what we did in a phone call. We essentially devised a protocol for bypassing it every time we started it. It was a pita. Wife and I are both retired Royal Canadian Air Force techs so we kind of understood the logic.

So we limped along like that for two years. Then it was time to do a coolant change in the generator. Our mechanic dude who changed our various fluids on the Motorhome did an extended coolant flush of the generator coolant. Fired it up and low and behold whatever corrosion was stopping the sensor from working must have been dislodged and it started working again. It was still working when we sold the unit.

Anyway. Something for you to try. (The coolant flush that is).

Hope this helps.

 

[Richpatty]

Thanks! I had thought of flushing the system since it would not cost very much and I would not have to take anything apart. We don‘t travel again for a few months so I may try that first and see what happens. I guess the only trick is that you usually have to have it running a while flushing and if the thing quits it might not get it clean…

Thanks so much for your reply and if the flush fails, I will reach out for a phone call. Thanks for the offer.

 

[Voyageurs]

Thanks! I had thought of flushing the system since it would not cost very much and I would not have to take anything apart. We don‘t travel again for a few months so I may try that first and see what happens. I guess the only trick is that you usually have to have it running a while flushing and if the thing quits it might not get it clean…

Thanks so much for your reply and if the flush fails, I will reach out for a phone call. Thanks for the offer.

My pleasure Rich. Good luck.

 

[Richpatty]

Well, it’s been almost three weeks since this problem first surfaced…. So today, out of curiosity, I thought I would start up the generator (we are home) and see what happens. Sure enough, it ran great. I ran it for about 40 minutes with a decent load on it to give it some overdue exercise and it never had an issue.

So does this mean I just saved an expensive repair? Maybe, but I am not hanging my hat on it. I will continue to run it periodically to see if it reoccurs and keep everyone posted. Hopefully it keeps running until I have to replace the belts or some other maintenance and just do this sensor at the same time.

As a side note, I never heard back from the Charlotte
Cummins shop (now over two weeks later). I called the Cummins shop in Spartanburg, sc last week, but have not heard from them either. How is a person supposed to get these things fixed?

I have a reprieve, but I am not sure I am out of the wood….so if it dies again, who ya gonna call?

Rich