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.

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

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.

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.

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.

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?

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.

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.

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)

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.