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Ready_set_go's avatar
Ready_set_go
Explorer
Jul 01, 2023

Won’t start

Engine would not start 2011 Tiffin Allegro Red Open Road 36’
Isb6.7 CM2250
We had drove for about 6 hours stopped twice at rest stops about every two hours no problem starting. Third stop for fuel after fueling motor would not fire up motor turned over but would not start up. Let set for three 30 min intervals tried to start each interval and still would not start. Then waited for another 60min and engine started.
So after engine set for 2.5-3 hours it started.
This is second time this happened last year it did the same thing except we were at a location we could let it set overnight and it started right up next morning. Took into mechanics after first event and they could find nothing wrong.
Any ideas. Vapor lock-fuel pump-on????
  • Did you let the engine idle for awhile when you pulled into the station? It takes a few minutes of idle to let the engine (and turbo assuming it has one) cool down properly.
  • When an engine is shut down it gets hotter due to lack of cooling and then cools down, could be related. I'd check/clean all electrical connections. A good Cummins mechanic will know the most likey suspects but shotgun repairs can get expensive. Have you checked for codes if any?
  • Were you really low on fuel? Does that engine have a lift pump? ( fuel ) Can you
    hear it run when turning the key on? How old are your fuel filters?

    I suppose it could but I never heard of diesel vapor lock.
  • It could be an electrical item that when it heats up it goes open. First thing to check is connections on fuel cut off valve.