R1150RT Fuel System Failure and Warning Light.
A few days ago, doing 75 mph in the passing lane, my motorcycle started to feel slightly starved for fuel--slightly low power at full throttle. It took about 8-10 miles before the condition progressed and engine stopped dead. After a 2 1/2 hour wait and 100 mile tow (thank you BMWMOA Platinum Club), I've debugged this to the point that I know the problem is inside the tank (lots of fuel flow but no pressure) and will drain it (it's full of course) and figure out what's wrong later today.
Since the failure, I've been thinking about adding a low fuel pressure annunciator. Has anyone done this, have experience doing it on another vehicle, or have a suggested pressure switch?
The normal pressure in the fuel system according to the BMW spec is 3 bar (43 PSI), +/- 0.2 bar--a 14% range, which means without an O2 sensor AFR has a 7% range Open Loop but that's another thread. My understanding is that the fuel pump can put out 60 PSI or more which means that the return pressure is 10 PSI or more while the injectors are consuming fuel.
My thought is to put a 5 PSI (nominally) sensor switch in the return line and then connect that to a light on the front panel that would signal low return flow. If the pressure dropped below 5 PSI, that would mean the pump or hose or filter or something was acting up. My reasoning on the return line is that it might not be a good idea to add a connection on the high pressure line.
What do you think?
Unfortunately this is typical
[QUOTE=Roger 04 RT;797046]Guys,
Thanks for the continued support and suggestions. As you'll see below, this project continues to have a life of its own. Everything is getting replaced.
I just looked up 30R7 hose after reading those articles. It is a non-submersible, low pressure fuel hose. So guess where I found it?
Earlier I had mentioned leaking internal vent and drain lines inside the tank just after I bought the bike. The seller replaced both internal lines with new hose and triple/double oetiker clamps on each end. The new submersed hose is marked SAE 30R7, clear as day. This explains why it ripped so easily when I removed the fuel pump plate.
This makes the dealer/seller replacement of the fuel filter a 100% incorrect job. It's hard to be so perfect.
The fuel supply system is too unobservable to tolerate this many errors. Everything is going to be replaced.[/QUOTE]
Unfortunately, this is all too common. What happens is the difficult jobs get handed to the real mechanics and the new kids get the "simple" tasks like routine service needs. You now have evidence of how "routine" maintenance can go terribly wrong when trusted to persons who do not have the proper knowledge to do the task.