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Topic: Electrical Fire in the Engine Compartment (Read 1711 times) previous topic - next topic

Electrical Fire in the Engine Compartment

Our son, Dan, came over with his DW and their 8-month-old daughter and he and I headed to the shop to see if we could figure out what was up with the "reverse" problem on the U225 and if it could be easily fixed. We lifted the bed but couldn't see the shifting plate so he grabbed a walkie-talkie and headed outside. I had chocked both sets of rear wheels so we could try the shifting without too much danger.

Checking the linkage out without the engine running wasn't showing us anything so he rigged a way to pull down on the shift plate while the engine was running and the selector was in "R". He heard the engine change note but couldn't hear me on the radio so he came inside and thought he smelled an acrid odor.

He headed to the bedroom and there was smoke coming from the main wire bundle across the engine. He told me and I shut the engine down but the smoke continued. I went to the battery compartment and started disconnecting the batteries.

Just about then the engine started up all by itself. Trust me when I tell you that it was a shock!

Dan was calling 911 when I managed to get the engine start battery disconnected and the engine died. This also removed the power from whatever it was that was causing the wiring bundle to smoke.

After everything cooled off I discovered the cause of the problem. A couple of months ago I had the alternator repaired and discovered that someone had removed the battery "sense" wire completely. I couldn't find it at all. This is the wire that comes directly from the batteries and that the alternator's voltage regulator uses to determine output current.  They had, incorrectly, jumpered the sense terminal to the positive output of the alternator. So I rigged a battery sense wire from the remote start switch near the radiator and removed the jumper.

It looks like whoever had removed the original sense wire had merely stuffed it up into the wire bundle. It was too far up to find easily but not so far up that it wouldn't fall out with enough vibration. They had also not taped up the terminal!

Since our Cummins 5.9B seems to vibrate a lot more at idle... and Dan and I messing around with the gear shift had been idling it quite a lot... the wire apparently worked its way out and fell down onto the engine exhaust manifold causing a dead short from the start battery to ground.

And the engine starting up on its own was probably caused by a wire from the ignition solenoid getting its insulation burned off and touching 12vdc from either that sense wire or some other wire. There are quite a few wires in that bundle that are burned. Plus the "sense" wire probably all the way to wherever it connects to the battery. And perhaps more.

We disconnected all batteries and the shore power and aired the coach out. Looks like the bedding will need to be washed. And I have a week or two ahead of me tracing and splicing all the wires in that wire bundle.

Battery disconnects would have been handy and quick. And I'm going to fuse that new sense wire I put in!

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical Fire in the Engine Compartment

Reply #1 –
Craig, Sorry to hear of your experience.  In an older coach you can never know just what --------- engineering has taken p[lace by a previous owner and I know of no way to figure it out til you have a near disaster as you had.  Good luck with finding the problems and Getting them fixed.
Gary B

Re: Electrical Fire in the Engine Compartment

Reply #2 –
               Wow Craig. Glad it wasn't worse than burned wires. I fully agree with the battery disconnects. I have them on my boat and I have been contemplating installing them on the coach at both start and house batteries.
      After reading about your experience I think it's a done deal.

      Dean
Dean & Deirdre

2012 Arctic Fox 22GQ
Was 2003 U270

Re: Electrical Fire in the Engine Compartment

Reply #3 –
Amazing story Craig. I am so sorry about the me but am glad you are all okay. Thanks for the thoughts about battery disconnects. Michael
Michael & Ginny
Frankfort, KY
1992 U240 GV Build #4116
2007 Mini Cooper

Re: Electrical Fire in the Engine Compartment

Reply #4 –
Quote from: wa_desert_rat –

Battery disconnects would have been handy and quick. And I'm going to fuse that new sense wire I put in!

Craig
Totally agree...
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Electrical Fire in the Engine Compartment

Reply #5 –
Wow.  You can't make this stuff up!!  Great detective work!
Carol & Jeff Savournin
Usta have a '93 U225 36', Usta have a '95 U320 40', Usta have a '02 U320 40'
Usta have a 2006 Born Free, Usta have a 2011 Phoenix Cruiser
Usta have a 2012 Jeep Wrangler Unlimited 4dr
"Your time is limited, so don't waste it living someone else's life."  Steve Jobs

Re: Electrical Fire in the Engine Compartment

Reply #6 –
My sense wire had also came disconnected from the alternator.  Just found when I had a new cylinder head installed.  I told them to check the alternator because it was not showing a good charge.  Thank goodness it did not connect with any ground!!!  Glad you caught your in time.

Still wanting to install 3 automatic fire extingusher systems.  Engine compartment, frig compartment and generator compartment.
1994 U225
build #4514

Re: Electrical Fire in the Engine Compartment

Reply #7 –
Quote from: PatC –
My sense wire had also came disconnected from the alternator.  Just found when I had a new cylinder head installed.  I told them to check the alternator because it was not showing a good charge.  Thank goodness it did not connect with any ground!!!  Glad you caught your in time.

Not exactly "in time". That wire bundle holds a lot of wires; including the controls for the exhaust retarder and I suspect the wiring for the Banks. Waiting for this cold spell (40F) to pass before getting into it any deeper. My initial inspection indicated that the only wire that was actually burned in two was that sense wire but if there are more it might be an interesting repair job.

Quote
Still wanting to install 3 automatic fire extinguisher systems.  Engine compartment, frig compartment and generator compartment.

I am not sure how well an automatic system will work in the engine compartment.
Since it's wide open at the bottom any gas will simply flow out (while the fire sucks more oxygen in) and water would not be useful for either an electrical fire or a fuel-driven fire. Foam might work though.

The most useful thing in our case would have been quicker disconnects at the battery terminals as that shut down the engine which was running without control (turning the ignition key off did not have any effect) but not running away (running at idle) AND removed the source of the heat (the power heating up the wires) and everything then cooled off.

We did not have any flames, either. Just a lot of smoke and a glowing wire (the shorted-out sense wire).

I would suggest that every owner check that the sense wire is fused!

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical Fire in the Engine Compartment

Reply #8 –
I met another FT owner the other day and introduced him to the forum.  Hopefully he will join. 

Anyhow, a little while later after our conversation he came back to our coach and gave me a present.  I was very surprised but he insisted I take it.  He said that more folks should know about this and have it available in some form for their coach.  It was a 12 oz. can of COLD FIRE.  Here is a link Cold Fire Multi-Purpose Fire Fighting Foam & Extinguishers

COLD FIRE is a fire suppressing agent specially formulated to rapidly snuff out Class A,B,D and K
fires. Prevents reflash, safe to store, handle and use, leaves virtually no residue, and is environmentally
friendly. The chemical is water soluble and rapidly biodegradable. On Class B oil fires, the
chemical encapsulates the oil and prevents burning and re-ignition. Has the advantages of foam and
dry chemical without mess, specialized apparatus or contamination to our environment. COLD
FIRE® can be used in pumpers and all types of multi-use portable equipment.

The website has a lot of info to review including a link to the MSDS. The product is in use in the racing industry so it would probably work in sometype of an automatic system in a coach's engine compartment.

A very thoughtful gift to me and some food for thought for others...

On edit:found one other thread on COLD FIRE:  http://www.foreforums.com/index.php?topic=9477.msg42060#msg42060
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Mark & Mary Benko
Former coach: 2005 U295 3823
Jeep Cherokee, Honda Fit

Re: Electrical Fire in the Engine Compartment

Reply #9 –
Craig,
I think your fix will not be too bad since you have the mechanical Cummins Engine, if it were the computer version, the wiring could be a major issue/hassle indeed.
Either way I wish you very good luck on the fix.

Dave M

Re: Electrical Fire in the Engine Compartment

Reply #10 –
Another example of truck shops not knowing how to work on MH alternators.
Dwayne Keith
1992 U240
3116/MD3060

Re: Electrical Fire in the Engine Compartment

Reply #11 –
Quote from: wa_desert_rat –
Not exactly "in time". That wire bundle holds a lot of wires; including the controls for the exhaust retarder and I suspect the wiring for the Banks. Waiting for this cold spell (40F) to pass before getting into it any deeper. My initial inspection indicated that the only wire that was actually burned in two was that sense wire but if there are more it might be an interesting repair job.
Don't you have a good friend who is a telephone cable splicer?  Would be a real easy job for someone like that.
1994 U225
build #4514

Re: Electrical Fire in the Engine Compartment

Reply #12 –
Craig,
          You might look into these. Called "solder sleeves" they work great. If you use them you need the correct sizes and a heat gun that has a curved nozzle that wraps the heat around the whole wire. I bent up a nozzle but you can buy them. Try a few outside of your bundle to get used to them then attack the rest.
Good luck,
Rick
Rick

Re: Electrical Fire in the Engine Compartment

Reply #13 –
Quote from: Rick –
Craig,
          You might look into these. Called "solder sleeves" they work great. If you use them you need the correct sizes and a heat gun that has a curved nozzle that wraps the heat around the whole wire. I bent up a nozzle but you can buy them. Try a few outside of your bundle to get used to them then attack the rest.
Good luck,
Rick

Thanks, Rick. I saw one of those little splices in another bundle and wondered where to get one. I have two warm days coming up (59F predicted) so I hope to get a start on this. Not sure I can even find these anywhere on a weekend though. :(

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical Fire in the Engine Compartment

Reply #14 –
West Marine or another boating store should carry Anchor Marine waterproof butt splices.

Re: Electrical Fire in the Engine Compartment

Reply #15 –
Quote from: Bob McGee –
West Marine or another boating store should carry Anchor Marine waterproof butt splices.

Thanks!!! Nearest West Marine is in Spokane about 100 miles east. Nothing in Richland/Kennewick/Pasco darn it (where our daughter lives). Our predicted 60-degree weather will not pan out today... barely 50 right now. So I might opt to take the 30mpg Kia to Spokane and get a bunch of these. They sound like the best route to go.

Thanks, again.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical Fire in the Engine Compartment

Reply #16 –
Just my luck... there are about ten West Marine stores in WA state and the only one that closes on Sunday is the one closest to me (but still 100 miles away). The one in Bellevue, WA is about 150 miles away but across the Cascade Mountains. So I have to wait until tomorrow which means the DW won't get to go with me and have dinner at Red Robin. :(

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."

Re: Electrical Fire in the Engine Compartment

Reply #17 –
I decided to look around town here more closely before I make the 220 mile round trip looking for those Anchor waterproof butt connectors. I found some (by another name and producer) at Home Depot. I pretty much cleaned them out of the 16/18/22 sizes. LOL

Price was pretty good... about $4 for 7 splices.

I was going to work on the coach this week but the hospital trip interfered with my plans.

Craig
1993 U225 36' Unihome GV with PACBRAKE exhaust retarder, Banks Stinger and Solar Panels.
Toad: 1999 Jeep Wrangler 2-door soft-top.

"No one has ever had to evacuate a city because the solar panels broke."
 

Re: Electrical Fire in the Engine Compartment

Reply #18 –
Craig,
Bummer about the Hospital set back, I am glad it worked out so well for you! Is 16 the largest they carried? I would expect some of those wires to be much larger as in 10 or 12 gage... I just ran a bunch of 10, 12, and 18 gage, as well as some cat 5 for future use from both sides of the utility compartment up through the tunnel as well as some spare flex conduit. It seems like most of the wires that interface with the water heater are 12 gage on the DC side of it. Heck, even the utility light in the water pump are seems to use 12 gage... Anyway, I usually upsize wiring when I run new stuff.
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson