Cranking problems update

[smiybrneyes]

Ok, not cranking but starting problems. Look for previous discussion under Cranking Problems. Finally got around to taking my 2000 Coachmen Catalina to a big truck mechanic for a scan. $90 later and still no definite answers. Scan codes simply said "lean fuel." I was told that could mean several things. They checked and I heard one tell the other, "its getting plenty of fuel." I have researched symptoms of a bad fuel pump, pump housing, and fuel injectors and none describe mine. Mine idles smooth, does not misfire, does not skip, runs smooth and perfectly, and starts immediately when cold or on short distances. Only problem is after running awhile it cranks but will not start until it sits awhile and cools down. I cannot throw more money toward a guess, like a new fuel pump without knowing without doubt that is the problem. Any suggestions as to how to find out for sure?

[Grey Ghost I]

On older units, I would say it it is definitely vapor lock.

[twinboat]

Originally Posted by Grey Ghost I

On older units, I would say it it is definitely vapor lock.

Most modern engines are equipped with*fuel injection, and have an electric*submersiblefuel pump in the fuel tank. Moving the fuel pump to the interior of the tank helps prevent vapor lock, since the entire fuel delivery system is under positive pressure and the fuel pump runs cooler than if it is located in the engine compartment. This is the primary reason that vapor lock is rare in modern fuel systems. For the same reason, some carbureted engines are*retrofitted*with an electric fuel pump near the fuel tank.

A vapor lock is more likely to develop when the vehicle is in traffic because the under-hood temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case.

[GraySeal65]

Check for a rpm reading during the no start, crank position sensor may be bad I would also watch the coolant temp sensor to see if it is reading properly.