R1150RT cuts off and will restart after 4 min.

[Cdup]

I've had a couple of updates to an earlier question - The original question is below.

I worked through some of things Twisty and David advised me to try. What I've found is thsy once she cuts off, when you turn the key back on I do not hear the fuel pump starting up, after 4 or 5 min the pump starts and she will fire up. Besides a bad fuel pump, could it be something else? It just seam odd for the pump to act this way. What controls the pump?

Thanks Chuck

-------------

My dealer and I have been working on this for weeks now. It's a 02 R1150RT. After riding anywhere from 10 miles on, sometimes the bike will sputter severely and at times it will cut off If she does cut off it will not fire for about 4 min and then zoom off like nothing happened. We had thought it was on the electrical side, but the Hal senser and the coil (single spark) have been replaced. Yesterday I was doing my own problem solving since it won't act up for the dealer. Once she died, I pulled the right spark plug (did it fast) and got spark, the other side was not firing. I now think there is no gas during that period. One other thing, if she sputtered I could roll on the gas and off we'd go, the spuddering stopped.

 

Any ideas? Screaming did not help.

 

[T__]

Chuck, the pump circuit is fairly complicated.. The fuel pump is controlled by the Motronic (fueling computer).. The Motronic controls the pump though a fuel pump relay (in the fuse box).. The fuel pump rely is powered by (I believe) the # 6 fuse in the fuse box.. The Motronic powers the pump for a few seconds at initial key on,, then it keeps the pump running based on the Hall effect sensor input during cranking & running.. Does your pump come on during cranking (even when it appears to not be working?)

 

Make sure the fuse doesn’t have a hairline crack inside it.. Maybe try swapping relays..

 

Otherwise rig up a test light to the fuel pump feed wire then monitor for that actually getting powered up at key on.. If not then move the test light the pump relay input & then to the pump relay output..

 

 

Twisty

 

[David R]

I am going to take a shot here.

 

I just bought my 11oo last night, so this is based on automotive exp.

 

First replace the fuel pump fuse with another one. If you don't have one, swap it with another one of the same amps from the fuse box.

 

You have nailed most of the problem. Next hook a wire and bulb (test light) to the power and ground sides of the fuel pump.

 

Run the bike till it quits. Turn the key off and back then crank the bike and see if the light comes on.

 

If it does and the pump doesn't run its the fuel pump.

 

If it does not, go back to the relay. Pull it out. With the key ON One terminal should light the test light all the time. (power to the relay)

 

 

I am not a BMW mech, but auto and truck mech and the fuel system is similar.

 

As for what controls the pump, the computer turns it on and off. I don't know if it uses + or - to turn the relay on (which controls the pump). ON cars its - .

 

If there are 4 terminals on the relay, One should be hot all the time with the key on. One will be on for a few seconds upon turning the key on if the computer controls the relay with + power. If it controls the relay with - then two will be hot all the time with the key on.

 

The relay could possibly be heating up. So could the pump....

 

I don't replace anything until I know what is wrong.

 

Good luck, I'll be back tonight.

 

Going to pick up my 2000 R1100 RT today.

 

EEEeeeeHhaaa!!

 

Twist has it, I just re read his post. Not trying to step on any ones feet.

 

David with big azz grin.

 

Edit: Check for good grounds. Check for poor connections but this has to be done under load.

[Cdup]

Thanks Again guys! I had replaced the fuse so on to trying power to the pump. I'll update this link I find it soon, if not I'll start another just so everyone will hear what the problem turned out to be.

Chuck

[timboaz]

I had a similar problem with my 1996 R1100RT and it took forever to find. The rubber hose inside the fuel tank went bad and split. It would work under heavy acceleration for a while but not well otherwise. It was a cheap fix, but hard to find.