DASH LIGHTS, ENGINE STALL, SUSPENSION

[Urban Hermit]

Bought a 2006 Cayman 36STB in early April with a howl in the drive train that occurred only at exact balance between pulling and compression slowing.   Drove it 750 miles home and put it in the shop.  Shop said (a) coach is running nose-high and that might be affecting the drive train, which  is designed to move only through a very few degrees; (b) a rear air bag is completely flat; and (c) the drive shaft was out of phase., and that all three conditions could be involved in causing the howl.  The drive shaft has been phased, the front end lowered until the coach rides flat, and -- I assume -- at this point the air bag has been replaced.  This is all background to the question to come. 

I contacted the previous owners by mail.  They phoned me and were most gracious and helpful.  They told me they'd had the front of the coach raised because -- here it comes:

When they bought it as second owners, if both front wheels hit a bump at the same time the dashboard lights would either all go on or all go off (I forget which he told me) and the engine would momentarily stall out and restart itself.  Multiple shops tried to find the problem and could not.  When the front end was raised the phenomenon stopped. 

Now --- anybody ever heard of this?  Any ideas/answers/references to Nostradamus?

The coach is still in the shop waiting for parts cost information  so it hasn't been driven except to test the drive line after the repairs, so I don't know what to expect when I come off a poorly-matched bridge/blacktop transition. 

Edited May 3, 2020 by Urban Hermit
verb tense correction

[Onthego]

That sound like a wire is grounding out.  They is a known problem with the trailing arms on the Cayman with a RR4 suspension. Check to see that has the upgrade install.

[Dennis H]

I'd check the wiring while it's in the  shop. A lot of the wires go through the frame rails and while many are in looms they are still flopping around loose. When I bought my rig, one of the first things I did was stop by Home Depot and bought one of those huge bags of zip ties. Every 12" or so the wires in my coach are zip tied. A little OCD? Perhaps. But, consider what happens to a piece of wire that you bend back a forth a few times. It breaks right? All those wires bouncing up and down as you travel will take it's toll on your wiring. Sounds like there's a loose, broken or chafed ground wire in your coach. I am assuming it's most likely a chafed wire somewhere through the frame rail. That's where I'd start looking. My thinking is when they raised the front end, however they did that, the bad wire was moved slightly and the problem was eliminated. At least eliminated until it slides back and grounds out again. Of course, you could simply wait it out and it may never resurface....good luck...Dennis

[Urban Hermit]

3 hours ago, Dennis H said:

I'd check the wiring while it's in the  shop. A lot of the wires go through the frame rails and while many are in looms they are still flopping around loose. When I bought my rig, one of the first things I did was stop by Home Depot and bought one of those huge bags of zip ties. Every 12" or so the wires in my coach are zip tied. A little OCD? Perhaps. But, consider what happens to a piece of wire that you bend back a forth a few times. It breaks right? All those wires bouncing up and down as you travel will take it's toll on your wiring. Sounds like there's a loose, broken or chafed ground wire in your coach. I am assuming it's most likely a chafed wire somewhere through the frame rail. That's where I'd start looking. My thinking is when they raised the front end, however they did that, the bad wire was moved slightly and the problem was eliminated. At least eliminated until it slides back and grounds out again. Of course, you could simply wait it out and it may never resurface....good luck...Dennis

I hope it's a simple as that, though it would mean that each of the several shops the previous owner too it to missed the chaffed wire(s) or didn't even think your thoughts -- and mine.  My other observation is that if a ground wire is ground out, it makes no difference.  But a loose ground wire connection disturbed by frame movement could for sure.  I haven't told the present shop, a Freightliner dealership's parts and service facility, that story.  I see is should.   Thankee .

6 hours ago, Onthego said:

That sound like a wire is grounding out.  They is a known problem with the trailing arms on the Cayman with a RR4 suspension. Check to see that has the upgrade install.

Indeed -- and I had the dealership send me photographs of the trailing arms before I traveled to look at the coach and  matched them to the photographs a nice lady at Monaco sent me of the revised trailing arms.  Thank you for the thought.

[OhReally]

I strongly agree with the loose wire diagnosis. Unfortunately it could be a anywhere from front to back bumper.

Typically a shop will not spend the time to view all wiring and may not even be able to in a Monaco, so I'm afraid you are left with only two choices, level the coach correctly and give it a try and/or do the wiring chase and tie yourself. 

Raising the front end to compensate for the problem you describe is surely a Mickey Mouse "fix". Certainly nothing I would ever entertain.

Good luck.

-Jamie

03 HR Scepter PDT

[walt2137]

And have the ride height set , if you dont know the ride height do a search or check the files.  You should also Have a dash ground bar behind the dash or on the fire wall  and it is a known problem most owners clean the wires and tighten the screws.

if raising the front solves the problem then that is where i would start, the wire looms are generally run through a 2 inch pvc  pipe from the rear axle  to the front just behind the front axle.

Edited May 3, 2020 by walt2137

[Urban Hermit]

1 hour ago, walt2137 said:

And have the ride height set , if you dont know the ride height do a search or check the files.  You should also Have a dash ground bar behind the dash or on the fire wall  and it is a known problem most owners clean the wires and tighten the screws.

if raising the front solves the problem then that is where i would start, the wire looms are generally run through a 2 inch pvc  pipe from the rear axle  to the front just behind the front axle.

It's in a freightliner shop, and they did set the ride height.  Also found a rear air bag collapsed and I assume have replaced it -- if they haven't they will.  Good info about the ground buss bar behind the dash -- hope it's easily accessible from inside -- and the PVC conduit.  Both helpful info.