FYI Starting procedure for your Cummins engine...

[Neal]

Open for discussion, I'm 7 years into ownership of my 2017 Newmar Ventana with a Cummins ISL 9 (400 HP) and still learning, it seems. This same topic came up at the Newmar Hoots rally this past October about how to start your engine, so it seems not everyone knows and not everyone is doing it right, and that may have included ME.

What I do know is when turning the key on WAIT until all of the lights go out, including the glow plug yellow lamp and then start. However, about a year or two into ownership of mine something got my attention in that the yellow outline lamp didn't go out, it remained on. When I needed my head gasket replaced (under warranty) at Tucson Cummins I asked the tech about this and he said that's normal because there's no oil pressure. Now keep in mind, just like tire pressures, these techs are not the know it all be all word of gospel and he may in fact be wrong on this one.

I had a phone conversation with @Rich W. when I put out my batman spotlight in the sky asking for a call as I was on the side of the road and wasn't sure about something with my Diesel Laptops Handheld device performing a forced regen to clear a problem. Somehow we got on the topic, I think he initiated it, asking me if I waited for the yellow outline lamp to go out on startup. I told him NO, mine never goes out. He said wait 30 seconds, it should go out and you should wait for this before starting the engine. Hmmm, okay, so I said I'll try it tomorrow (which was today). Sure enough, 10-15 seconds after all of the other light bar lights go out the yellow outline lamp went out. So from now on I will be patient and wait for it to go out as well prior to engine start. Can't hurt and maybe it is required for the ECM to do its preflight of everything to ensure all are in parameters? I'm not a Cummins expert or engineer, so let's discuss and learn from each other. This is the very reason I created RVForums.com is peers are so crucial to learning this lifestyle. There are some pretty complex parts to learn with these coaches as our sources of knowledge and education by the manufacturers are extremely lacking.

So share what you know, what you do, and maybe you too can help someone here as @Rich W. did for me yesterday. Our phone call is a 1:1 conversation so others can't learn from that so this is why I'm posting it and I welcome others to please share your knowledge and help our wonderful RV family and peers do things for the better.

 

[J&JD]

I have been told by several techs to wait for all the lights to go out prior to starting. It seems like an eternity, especially when someone is waiting for you to start. But in reality it’s never more than about 12-15 seconds.
Interestingly the techs rarely follow their own advice, however.

 

[Rich W.]

Below is a quote from a thread at “that other place” (from which I’m proudly banned for life) from Dutch Star Don on the subject when it came up in 2019 (while I was still in good graces there). It covers most of the issue, but one more rationale for waiting to start until the CEL goes out is that running the starter motor could create a voltage spike (or maybe excessive draw?) while the ECM is going through its pre-start checks damaging it or causing false or phantom codes.

It’s also possible that none of this matters, but enough credible folks have made the point over the years that I follow the procedure religiously. Interestingly my tech at the Mothership had never heard of this and I cringed when he started my rig without waiting. We had the discussion and he agreed that it made sense, although he might have just been patronizing me out of a high degree of customer service.

Anyway here’s the quote from DSD in 2019:

“This is a common Freightliner issue and has been going on since at least 2014 and now on my 2019. When you turn the key on, all of the idiot lights will illuminate and tell you that they're working. If it's cold out, the "Wait to Start" light will illuminate. The YELLOW "Check Engine" light will stay illuminated for about 20 seconds or so, even after the "Wait to Start" light is off. Apparently, the YELLOW "Check Engine" light stays on until all of the various computers talk to each other......then the "Check Engine" light will go out.

If you DON'T wait for the YELLOW light to turn off and start the engine, it will start and run fine, but will often throw a code a few miles down the road, turning the YELLOW "Check Engine" light back on. It will eventually go out after a few starts.

Sooooo….if you own a newer Freightliner, wait for the YELLOW "Check Engine" light to go out. I can't say for sure this is an issue on all Freightliners, but it is on the Newmar Dutch Stars with the Freightliner chassis.”
__________________
Don & Mary

 

[MemoriesByTheMile]

Interesting … now you made me super curious. But I cannot check the rig right now, but maybe tomorrow I can get time to check this out in our SuperC with a Cummins ISX/15-600.

Always good to learn something new

 

[jaydee325]

It's not rocket science!

Turn key on. Wait for glow plug light to go out. Turn key to start. Check engine will stay illuminated after start and will go out (on mine anyway) after a few seconds. At that point, I'm waiting for air to come up. Things settle out fine then.

I've got a 2018 Ventana on a Freightliner chassis bought used in spring of 2022. Following the above, no issues along the way.

 

[Rich W.]

Here’s one from a different thread on the subject “over there”, this one from BroBox in 2018:

“Here is what I read in the owners manual. There are 16 DEF sensors that have to talk to each other before starting. Interrupt the communication and a DEF error message with CEL can come up that has to be cleaned by Cummins.

On the 450 it was the CEL, and the 1081 code that could go away in a couple of starts, or like mine last 1,000 miles. It also took a reprogramming from Cummins to finally stop all the bogus 1081 codes. The 450 took 35 seconds for the check engine light to go off, the 605 take less than 20 second. The "wait to start light" goes off instantly, if I even see it. But do wait for the amber engine light to go off before starting.”

So even if it’s superstition, urban legend, or just being paranoid, I wait the 20 seconds or so for the CEL to go out before I start because it’s an easy precaution to take and I view the emissions system as fragile at best.

 

[team bradfield]

Before this MH, always drove F-450's, the old 6.0 would not start until glow plug light went off, my newer 6.7's you press start button and had a delay before starting, with this Spartan, Cummins 450, I was prepared for diesel starts, noticed the wait to start warning right away, as @richw explained, I do the same, wait till all.is clear, then start

 

[Crazydog]

Does the owner's manual tell you to wait until the check engine light goes off? I'm guessing no.

There is no mention of that procedure in my Cummins/RAM owners manual either. You only need to wait for the glow plug/heater grid light to go off.

 

[Texas Clodhopper]

I started yesterday using the wait until the CEL goes out and my lord, that 12-15 seconds seems like 2 minutes. I'm also in the 7-year program and have always waited for the only the glow-plug light to go out.

 

[Neemer]

The Freightliner rep who gave me “Freightliner 101” at FPU told me there was no need to wait on anything. Just turn the key and go. I have noticed all of the Newmar techs do that. Me? Of course I wait for the “wait to start” light to go out. Old habits are hard to break.