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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: surreybeemer on December 24, 2015, 11:29:14 PM

Title: Fuel pump keeps running.....is this normal?....SOLVED
Post by: surreybeemer on December 24, 2015, 11:29:14 PM: Hi fellow K riders...
I noticed that the fuel pump on my 1987 k75s keeps running as long as the ignitions key is in the on position even if the engine is not running. I thought it is suppose to stop after a few seconds if the engine is not turning like in most cars. I am not sure if this is normal or I have some problem that needs attention.
Thanks!!
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Inge K. on December 25, 2015, 07:28:26 AM: The fuel pump should only run when the engine running, or the start button is pressed.
The negative side of the FI relay coil is controlled by the ignition ECU.

It sounds to me that the problem is the ignition ECU (behind the headstock), or the wire
between the relay and ECU is shorted to ground (colour code, brown/yellow).
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Scott_ on December 25, 2015, 09:30:25 AM: More unlikely, but it could also be a stuck relay.
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Inge K. on December 25, 2015, 10:00:07 AM: Quote from: Scott_ on December 25, 2015, 09:30:25 AM
More unlikely, but it could also be a stuck relay.

Then the fuel pump also would run with the ignition switch in the off position.
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Gio on December 25, 2015, 12:31:35 PM: Drain entire fuel system and then flush with a 50/50 mixture of egg-nog / brandy. If no joy - re-drain and drink proceeds ... this won't fix the problem but will give you an entirely different perspective ...

Wishing you all the seasonal best fellow 'brickers!

Gio
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Scott_ on December 25, 2015, 01:32:02 PM: Quote from: Inge K. on December 25, 2015, 10:00:07 AM
Quote from: Scott_ on December 25, 2015, 09:30:25 AM
More unlikely, but it could also be a stuck relay.

Then the fuel pump also would run with the ignition switch in the off position.

Makes sense.
Title: Re: Fuel pump keeps running.....is this normal?
Post by: KRider on December 26, 2015, 04:54:20 AM: I have have almost the same but i can controle it with the deadmans button.
Title: Re: Fuel pump keeps running.....is this normal?
Post by: Inge K. on December 26, 2015, 05:06:21 AM: Quote from: KRider on December 26, 2015, 04:54:20 AM
I have have almost the same but i can controle it with the deadmans button.

It's just the same, if the ignition switch or kill switch is used.
It's just cuts the power to the FI relay coil on different places along the line.
.
.
.
But if you have a 4V model the fuel pump runs for a couple of seconds and then stops,
when you turn on the ignition switch (or kill switch)...this builds up the fuel pressure.
Title: Re: Fuel pump keeps running.....is this normal?
Post by: KRider on December 26, 2015, 12:18:16 PM: Thanks Inge K so surreybeemer and me have same problem. Will look at it soon.
Title: Re: Fuel pump keeps running.....is this normal?....SOLVED
Post by: surreybeemer on January 17, 2016, 08:49:11 PM: Finally it is all good. I took the fuel pump out, cleaned all the connections going to the fuel pump. Also cleaned the low fuel light mechanism attached to the float, it was rusty and gummed up. Cleaned the connections under the tank and to the ECU. Put it back together and it works normally. I can hardly hear the pump running and no more whizzing noise. The bike starts with one light push on the button...it is all good.
Big Thanks to you guys!!
Here is a pic of the final product.
Title: Re: Fuel pump keeps running.....is this normal?....SOLVED
Post by: WayneDW on January 17, 2016, 10:32:22 PM: Beautiful bike!
Title: Re: Fuel pump keeps running.....is this normal?....SOLVED
Post by: The Mighty Gryphon on January 18, 2016, 10:23:38 AM: The K75S, porn star of the K bike line...