37' BMC,will not start

[Randy Dupree]

Lee davis called me on friday,the day the beach rally started.
He was at the campground on the beach,he shut down his engine when he went to pay for his site.
When he returned,his 8.3 cummins engine would not start.
It would turn over,but no start.

First question i had for him was this,how much fuel do you have?
he replied he had a full tank.

OK,the cummins in his coach is a mechanical engine,no computer.
And it has a fuel shut down solenoid,these solenoids very seldom go bad.
i had him take a look at it,while his wife tried to start the engine.
On this engine the fuel solenoid is very easy to see,its not built into the injector pump like the cats.

When she cranked the engine,the solenoid chattered,and it would not engage.
so,i had him hold the solenoid plunger in,while his wife started the engine,it started and ran fine!
The solenoid is a two stage deal,one stage pulls the pluger in,and the 2nd stage holds it in.
I suspected it had a bad ground,and when i got to the beach we looked it over and the ground wire was indeed loose,we tightened the wire and all was well.

Lee had had this item replace a year ago,and i wonder if it had a loose wire then as well?

[gcyeaw]

I had a similar experience with my Perkins diesel. It would start and run, but once warmed up, if I shut it down it would not re-start. I observed the fuel solenoid action and it would drop out right away. I replaced the ground wire and it has worked ever since.

[AC7880]

I had just the opposite problem in late 2004. The solonoid would open for the start, but running down the road it would lose holding power and close, shutting off the engine running down the road at speed. This happened on the maiden trip home with the coach, before I knew very much about the BMC and Cummins.

On the second day I figured out I could tie a small loop of thin rope to the solonoid pivot point, then use a thin cargo strap through the loop pulled straight back to the rear of the coach upper rear frame member.

I would start the coach, tighten the cargo strap to securely "winch" the solonoid open - no more cummins dying going down the road. When ready to shut down, I would loosen the cargo strap, then turn off the ignition key, or rear kill switch.

Long term fix was a new solonoid. I now carry the cargo strap and a small piece of rope in case it ever happens again.

The other thing I experienced that can strand a BMC is the speed sensor on the Allison. It happended right after (same day) the solonoid started killing the engine - which I think in turn damaged the speed sensor from at speed on the road in gear motor dying multiple times.

With a bad speed sensor, the Allison will enter safe limp home mode. Symptoms are it slowly downshifts one gear at a time, until you are down to 1st gear. One of these days I need to buy a spare to carry with me. After extensive cool down I could run a while again until it re-entered safe mode.

I had my speed sensor replaced by a Allison shop - and I still do not know where the speed sensor mounts on the tranny, or what it looks like - anyone here know?

Originally Posted by Randy Dupree

Lee davis called me on friday,the day the beach rally started.
He was at the campground on the beach,he shut down his engine when he went to pay for his site.
When he returned,his 8.3 cummins engine would not start.
It would turn over,but no start.

First question i had for him was this,how much fuel do you have?
he replied he had a full tank.

OK,the cummins in his coach is a mechanical engine,no computer.
And it has a fuel shut down solenoid,these solenoids very seldom go bad.
i had him take a look at it,while his wife tried to start the engine.
On this engine the fuel solenoid is very easy to see,its not built into the injector pump like the cats.

When she cranked the engine,the solenoid chattered,and it would not engage.
so,i had him hold the solenoid plunger in,while his wife started the engine,it started and ran fine!
The solenoid is a two stage deal,one stage pulls the pluger in,and the 2nd stage holds it in.
I suspected it had a bad ground,and when i got to the beach we looked it over and the ground wire was indeed loose,we tightened the wire and all was well.

Lee had had this item replace a year ago,and i wonder if it had a loose wire then as well?

[bwinter1946]

Pictures of the solonoid and showing the location of the fuel solonoid the next time you are able would be appreciated.

Thanks,

[AC7880]

Kill switch at top, fuel solonoid behind and below it, brass color.
http://good-times.webshots.com/photo...28993757VoPdAF
http://good-times.webshots.com/photo...28993757nQJTyB

[iamflagman]

Using Dan's photo to further help illustrate what both Randy and Dan are talking about:


http://www.wanderlodgeownersgroup.co...&pictureid=305