Cummins ISB 6.7 Intermittent Starting Problem

[PaulInclaw]

Starting Problem:
I Turn ignition switch on, After waiting for all dash indicator lights to go out, I try to tip key to the right to start but nothing happens.

The only way it will start is to turn key ignition to off then tip to the right to start. Sometimes I may to do this up to 5 or 6 times before it will start. Without turning the ignition off and just attempting to tip to the right to start, there is a distinct click sound coming from the passenger side of the coach, roughly 3 or 4 feet behind the passenger seat. I have done a visual inspection as well as trying to locate the source of the click from underneath the coach with someone else turning the ignition key. I suspect there is some sort of relay there that is only working intermittently.

The ignition key switch has been replaced as well as the starter relay located in the rear of the coach. Starter and solenid work consistently when bypassing the ignition key and jumping the contacts on the starter.
Mechanics are baffled, and I have not been able to locate any diagrams that show the full extent of the starting circuits.
Very concerned that I may get stuck in the middle of nowhere, if the thing decides to just not work anymore.

Per Freightliner email support:
Possible causes: Issue in the TCM (transmission control module), neutral start relay, wiring, ect.
Based off your description my first guess would be the TCM is dropping the signal to the neutral start relay.

Would the TCM make a clicking sound? NO Where is located? Inside the left frame rail near the rear axle. Advised DO NOT go under the coach without the proper safety equipment.
*
Would the Neutral start relay make a clicking sound? *YES (not very loud) Where is located? Left rear near the condenser fan. Inside the ARENS PDM.
*
When you key on the neutral start relay should engage and stay engaged. The TCM supplies power to pin 86 of the relay. Should have ground on pin 85.

Starter lockout relay?

Any ideas?

[Skip426]

You mentioned " Arens " is your coach equipped with the Allison 2500 series transmission.

Another member with similar issues a short while ago , I'll track it down and link you to his post.

What year is your coach ?

If you do have the Allison 2500 series with the Arens SBW ( Shift By Wire ) system maybe some of the info on the Allison NSBU ( Neutral Start Back UP ) switch applies to your year .
Several links in this post on Arens problems.

http://www.irv2.com/forums/f125/2100...on-490151.html

[PaulInclaw]

Skip-
Here’s details on my coach
2011 Itasca Meridian V Class 34 ft
Cummins 6.7 liter pusher
Allison 2500 trans

I’ll check out the link you provided.
Thanks for your help!

[Skip426]

Your coach is new enough, that Freightliner should provide you with wiring schematics and diagrams , when you phone the help line with your serial number .
1-800-385-4357

Now , if Winnebago installed any kind of starter lock out ; for slides or leveling jacks , Freightliner wiring won't help.
You'd have to go to Winnebago.

www.winnebagoind.com/diagram/Wiring.htm

[deprived]

Did you ever get to the bottom of this?

[PaulInclaw]

Problem is still unresolved. Having a tough time finding anyone to take a look at it.
☹️
Thanks for asking.

2011 Itasca Meridian V Class 34 ft
Cummins 6.7 liter pusher
Allison 2500 trans

[shootist]

Originally Posted by PaulInclaw

Problem is still unresolved. Having a tough time finding anyone to take a look at it.
☹️
Thanks for asking.

2011 Itasca Meridian V Class 34 ft
Cummins 6.7 liter pusher
Allison 2500 trans

You didn't answer if you have slides or jacks?

[PaulInclaw]

Originally Posted by shootist

You didn't answer if you have slides or jacks?

Sorry, I have 3 slides and 4 hydraulic jacks.

[Canook]

I have had a similar problem with not starting as i turn the key, my unit is parked slightly uphill, and that sometimes seems to create starting problems, I have a push button transmission on the side , I hit neutral a few times and it will start, seems the transmission needs that extra little nudge to remind it... works every time, hope this helps

[PaulInclaw]

Resolved!
I’m not 100% sure, but I think the problem is resolved. Chassis batteries died so I had to replace them. In the process, I cleaned every connection near the batteries.
There is the main battery connection that screws onto the battery post, which I had previously cleaned. Then there are secondary connection to both positive and negative. I cleaned them thoroughly and now it seems to work just fine. I haven’t done much traveling since then, but have started it numerous times, and there has been no issue whatsoever.
The secondary connections I’m referring to are screwed onto the battery cable itself.

[Skip426]

Originally Posted by PaulInclaw

Resolved!
I’m not 100% sure, but I think the problem is resolved. Chassis batteries died so I had to replace them. In the process, I cleaned every connection near the batteries.
There is the main battery connection that screws onto the battery post, which I had previously cleaned. Then there are secondary connection to both positive and negative. I cleaned them thoroughly and now it seems to work just fine. I haven’t done much traveling since then, but have started it numerous times, and there has been no issue whatsoever.
The secondary connections I’m referring to are screwed onto the battery cable itself.

You've been chasing this issue for a long time, hopefully this is the fix you were after.

A previous owner of my coach may have had similar issues with all the small cables at the chassis battery, so he moved all positive and negative cables to a remote power/ground studs, to keep them clear of corrosion from battery off gassing. Now I have only a limited number of connections to clean, main cable to starter and one to the power stud. Thirteen years and no battery connection issues.