BMW K bikes (Bricks)

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1Back to top Go down   Flooding  Empty Flooding Fri Mar 19, 2021 12:26 pm

pgolav

pgolav
active member
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I have an ‘85 k100 that floods when I touch the starter button. This has me stumped. I have tried cleaning all the connectors and checked/cleaned all ground wires. Any help or suggestions will be greatly appreciated.

    

2Back to top Go down   Flooding  Empty Re: Flooding Fri Mar 19, 2021 12:56 pm

moriarti

moriarti
Life time member
Life time member
A blocked return valve possibly. Run a hose from the fuel rail into the tank, bypassing the valve and try starting it up again.


__________________________________________________
1984 k100 rs red/black VIN  0004449
    

3Back to top Go down   Flooding  Empty Re: Flooding Fri Mar 19, 2021 2:46 pm

Point-Seven-five

Point-Seven-five
Life time member
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Check the engine temperature sensor. Should be about 2500 ohms at room temperature dropping to about 250 ohms at normal operating temperature.

Another check would be if there is a short to ground in the injector wiring harness. Injectors work by having 12v at all times on one terminal, while the ECU pulses the ground connection to open them. If the harness is shorted, it's possible to have the injectors open all the time. Turn on the ignition and with a voltmeter check the voltage across the terminals in an injector plug. Should be 0 volts. If you get 12v it means that the injectors are being turned on.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

4Back to top Go down   Flooding  Empty Re: Flooding Mon Mar 22, 2021 12:37 pm

pgolav

pgolav
active member
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@moriarti wrote:A blocked return valve possibly. Run a hose from the fuel rail into the tank, bypassing the valve and try starting it up again.
Tried that and still the same.

    

5Back to top Go down   Flooding  Empty Re: Flooding Mon Mar 22, 2021 12:50 pm

pgolav

pgolav
active member
active member
@Point-Seven-five wrote:Check the engine temperature sensor.  Should be about 2500 ohms at room temperature dropping to about 250 ohms at normal operating temperature.  

Another check would be if there is a short to ground in the injector wiring harness.  Injectors work by having 12v at all times on one terminal, while the ECU pulses the ground connection to open them.  If the harness is shorted, it's possible to have the injectors open all the time.  Turn on the ignition and with a voltmeter check the voltage across the terminals in an injector plug.  Should be 0 volts.  If you get 12v it means that the injectors are being turned on.

I used a Mac tools FI test lite and no short in the injector harness. The light comes on when pressing the starter button. 

I tested the temp sensor and I’m getting 4.63 ohms.

    

6Back to top Go down   Flooding  Empty Re: Flooding Mon Mar 22, 2021 1:42 pm

Laitch

Laitch
Life time member
Life time member
@pgolav wrote:I used a Mac tools FI test lite and no short in the injector harness. The light comes on when pressing the starter button. 

I tested the temp sensor and I’m getting 4.63 ohms.
Can you explain how you are connecting the FI test light, and your connections for the ohms test of the coolant temperature sensor?


__________________________________________________
1995 K75 81,000 miles
Flooding  Usa-lo10
    

7Back to top Go down   Flooding  Empty Re: Flooding Tue Mar 23, 2021 2:48 pm

pgolav

pgolav
active member
active member
Yes, the test light has two small prongs that connects in place of the injector. It’s made specifically for this purpose. I removed a connector from an injector and connected this light. It lights up when I press the start button. Does the same on all injectors.

For the temp switch, I unplugged the connector and connected the  multiltester leads to temp switch. Each MT lead to each temp sensor prong.

    

8Back to top Go down   Flooding  Empty Re: Flooding Tue Mar 23, 2021 3:42 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
I'm pretty sure your test light should be off when you turn on the ignition, then pulse when the starter is running. What you are telling us indicates that there is a problem with the injector wiring causing the injectors to be turned on all the time, flooding the engine. Either there is a short to ground in the harness, or the ECU has a problem with the circuit that pulses the injectors.

In case you didn't know, the injectors have a steady 12v applied when the ignition is turned on. They are closed until the ECU grounds them. That ground is made through a transistor in the ECU.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

9Back to top Go down   Flooding  Empty Re: Flooding Tue Mar 23, 2021 3:47 pm

pgolav

pgolav
active member
active member
I think you misunderstood me. The light is off when switching the ignition to on and only comes on or pulses upon pressing the starter switch (motor turning)

    

10Back to top Go down   Flooding  Empty Re: Flooding Tue Mar 23, 2021 7:12 pm

Laitch

Laitch
Life time member
Life time member
@pgolav wrote:Each MT lead to each temp sensor prong.
That isn't how it's tested. 

The sensor is grounded through its body. One of those prongs leads to the LE Jetronic FI control and one leads to the temperature switch. One way to test is to ground pin #10 of the LE Jetronic control plug under the seat. Another way is to remove the sensor, immerse part of it in boiling water and record the ohms as the water cools. Click on the Portal tab at the top of this page. Click on the link to the Forum Tech Page. Find the document Troubleshooting the EFI then scroll down to the pages that show the coolant temperature sensor and Jetronic tests.


__________________________________________________
1995 K75 81,000 miles
Flooding  Usa-lo10
    

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