Author Topic: Fuel Issue  (Read 210 times)

Offline BobZ(IL)

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  • Posts: 121
Fuel Issue
« on: August 10, 2019, 07:13:16 PM »
Fresh gas, new fuel filter, bike may start and idle for about a second then die. Fuel pump seems to pump like crazy. Next?
  • Bourbonnais IL
'93 K1100LT
'78 R100S
'05 R1200GS

Offline daveson

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  • Posts: 445
Re: Fuel Issue
« Reply #1 on: August 10, 2019, 07:41:54 PM »
Overfueling usually from a faulty temperature sensor. Can you hear the injectors clicking with the aid of a screw driver?
  • Victoria, Australia
  • Current;'86 K100RT Past; '97 Yamaha V Star 650 Yamaha V Star

Offline Laitch

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Re: Fuel Issue
« Reply #2 on: August 10, 2019, 08:18:25 PM »
Fresh gas, new fuel filter, bike may start and idle for about a second then die. Fuel pump seems to pump like crazy.
How was it running before the new fuel filter was installed? Pump like crazy? Verify the correct orientation of the filter, that all hose clamps are tight and that fuel actually is coming at pressure from the hose that attaches to the rail when the starter is cranked. Check that the battery clamps are tight and that the battery negative cable is tightly attached to the transmission. 
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline Scott_

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  • Posts: 1984
Re: Fuel Issue
« Reply #3 on: August 10, 2019, 10:43:54 PM »
Hey there Bob, how's the spark. Being a '93, don't forget the ignition amp module.
TPS, within adjustment?
  • My Garage
Ride safe.


1997 K1100LT 0302488
1995 K1100LT 0302044
Garmin StreetPilot 2820
Garmin Zumo 550
"One who does not ask questions is ashamed to learn" Danish proverb

Offline BobZ(IL)

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  • Posts: 121
Re: Fuel Issue
« Reply #4 on: August 10, 2019, 10:47:55 PM »
Fuel pumps properly whenever a start is tried, however, I have no way to measure actual pressure. Engine just quit at highway speed. Need a little more explanation on checking injector click. Listen while attempting start? Thanks for the responses.
I'll pull a plug to check for flooding.
  • Bourbonnais IL
'93 K1100LT
'78 R100S
'05 R1200GS

Offline BobZ(IL)

  • ^ Proficient Motobricker
  • Posts: 121
Re: Fuel Issue
« Reply #5 on: August 10, 2019, 10:53:22 PM »
Hey Scott, hope you are doing well. Is the ignition amp module that part we put heat sink paste on? TPS adjust by turning engine over at full throttle? When I checked the spark on number one it seemed a little lame.
  • Bourbonnais IL
'93 K1100LT
'78 R100S
'05 R1200GS

Offline Scott_

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  • Posts: 1984
Re: Fuel Issue
« Reply #6 on: August 11, 2019, 07:00:10 AM »
Hey Scott, hope you are doing well. Is the ignition amp module that part we put heat sink paste on? TPS adjust by turning engine over at full throttle? When I checked the spark on number one it seemed a little lame.

Yes, the amp module is what gets the heat sink paste.
The TPS is set with a voltmeter, ignition on-engine off.

from here: http://www.k11og.org/forum/viewtopic.php?t=2110

Throttle Position Sensor (TPS) Test:
To test the TPS
Ignition OFF, Ground Pin #3 and monitor Pin #1 with a 12V LED (+lead to Battery + and -lead to Pin#1). Ignition ON, Engine OFF (Pin #3 should remain grounded during this test)
The Test LED will be ON at idle (closed throttle) and OFF just above idle. You should also be able to watch the temperature warning lamp on the tachometer blink ON at idle and OFF just above idle.
Pin #1 should be Low at idle and High just above idle. In other words, if you are measuring from ground to Pin #1 with a voltmeter, Idle should be close to 0 Volts and just above Idle should be close to 12 Volts. (This test also works for Oilheads (1994-2001) with Motronic 2.2 Engine control Units but since there is no temperature warning lamp, you must use either a voltmeter or a Test LED as described above).

NOTE: Measuring the voltage between pins 1 and 4 at the TPS connector should indicate
0.375 Volts at the idle setting (closed throttle) with ignition ON engine OFF.
Snap the throttle open/closed a few times to ensure a consistent reading. To adjust the TPS, loosen the two screws slightly and rotate the TPS until the temperature warning lamp (or the Test LED) 'just' comes ON at idle and goes OFF just above idle. If you are using a voltmeter, adjust the voltage to 0.375 at idle (closed throttle). This voltage MUST remain below 0.400 Volts at idle.
  • My Garage
Ride safe.


1997 K1100LT 0302488
1995 K1100LT 0302044
Garmin StreetPilot 2820
Garmin Zumo 550
"One who does not ask questions is ashamed to learn" Danish proverb

Offline daveson

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  • Posts: 445
Re: Fuel Issue
« Reply #7 on: August 11, 2019, 05:20:18 PM »
Try the other suggestions first. I was jumping the gun as I took "pumps like crazy " to mean overfueling. Later you say pumps OK.
  • Victoria, Australia
  • Current;'86 K100RT Past; '97 Yamaha V Star 650 Yamaha V Star

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 6732
Re: Fuel Issue
« Reply #8 on: August 11, 2019, 05:27:14 PM »
Fuel pumps properly whenever a start is tried, however, I have no way to measure actual pressure. Engine just quit at highway speed.
Your opening post didn't mention that it ever made it to a highway. How did you determine the fuel "pumps properly"? Did you disconnect the delivery hose at the fuel rail?
  • Along the Ridley in Vermont.
  • 1995 K75T 72,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline BobZ(IL)

  • ^ Proficient Motobricker
  • Posts: 121
Re: Fuel Issue
« Reply #9 on: August 12, 2019, 05:00:30 PM »
Try the other suggestions first. I was jumping the gun as I took "pumps like crazy " to mean overfueling. Later you say pumps OK.
Pulled a plug again to check spark. Strong. Plug looks damp. Had this problem before but can't remember cure. Will try heat sink first, then consider temp sensor. I've replaced sensor before and repasted the module previously but don't remember which solved the problem.
  • Bourbonnais IL
'93 K1100LT
'78 R100S
'05 R1200GS

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