TOPIC:

Hi all,
Got a problem with my gpz11 unitrack.
Was doing some testing of the control box (as per the factory manual) with a multimeter.
When I tried to start the bike, the fuel pump wouldn't prime (was fine before).
When I turn on the ignition, pull clutch lever and press the starter, I get a click from the relay, but the pump doesn't prime.
I've supplied power to the pump and it spins up, so its not the pump.
I've tested the pump supply leads as the manual suggests and I'm getting no power supply.
1. I've tried a spare relay and makes no difference.
2. Fuses are all OK
3. All connectors seem tight and have been cleaned with oxit spray.
4. All other electrics, starter cranks, dfi display, lights etc work OK
5. Only other thing I did was replace the engine stop connector as they were manky looking. Although if this was the problem surely it wouldn't crank the starter.

Pulling my hair out a bit as it was fine before. Everything else works, cranks the motor, just no fuel pump working!

 

woodyvale  wrote:

Was doing some testing of the control box (as per the factory manual) with a multimeter.

Something is wrong with your EFI control unit or connector, like a dis-located unpluged or bad wiring = Green/White to #21 pump relay drive connector.

 

I had to open the relay and clean the contacts with 800 paper. 
then happy days i got the pump humming again. Look at my build thread.

Then the FSM has got a excellent test schema to follow when trouble shooting.

/A

Thanks Scirocco, tried the test you suggested and the green/white wire is showing only 250Mv when ignition is switched on rather than battery voltage for 5 secs.
I've plugged in a spare control box and got the same result, so I'm hoping the control box is OK.

Could be a problem around the relay or connectors.

Scubaanders, I'll look to inspecting the relay as you did. I've also just ordered the VW Bosch relay as a back up in case the original one is toast.

 Is there a fuel pump safety switch on these bikes? Like an inertia switch?

Ok, think i’ve worked it out.
tested the relay as per the factory tests.

failed on testing conductivity between green/white wire in black connector to black/yellow in white connector - showing 0.82 instead of 0 ohms. Black/yellow wire is part of the ground circuit for the fuel pump.

i opened the relay and theres a diode in the middle of the connection which i guess has failed.

hopefully the pattern relay i’ve ordered will sort it out.

So it doesn’t seem to be the relay. Finally received a replacement main pump relay - and nothing. Still won’t prime the pump.

it cranks the engine fine.

i’ve run through the manual tests and its failing on the ‘starter signal test’

1. red/black wire at computer connector is not showing battery voltage.
2. black wire at main relay not showing battery voltage either.

both wires not showing resistance so seem ok.

green/white wire test also not showing battery voltage.

Connectors are all tight and clean.just doesn’t seem to be getting power.
 

Looks like your EFI control unit is your problem.

Dunno. I have a spare computer that ran the bike previously, which gives the same result when i plug it in now.

its driving me nuts!

Did you check your power connectors and wiring to the ECU

Ignition coils Bk and G, trigger signal from CDI unit (rpm) to the ECU = pulsing +12 Volt.
Triggers ECU, the pump relay drive and injector timing (engine running)
Switched power R +12 Volt from the ingition switch to wake up the ECU and pump relay drive (Priming only)

Ground Bk/G and Bk/Y to the pump relay and ECU

Switched power Bk +12 Volt from the starter relay to trigger the ECU, injectors and pump relay drive (engine e-start)

Permanent power W/R +12 Volt to the pump relay

 

Thanks for the info scirocco. I’ll give them a test once the weather cools down a bit.

Been over 40C for 5 straight days so the garage is a bit of a sweatbox at the moment.

Someone posted on a FB page about having the same issues and he found that there are 2 sensors inside the air mass sensor. He cleaned them out and the fuel pump worked.
I’ll look for the post and snap a pic