2002 F4i stunted out so its taken some beatings but i keep it nice.
Anyway, about a month ago I had this bike running since then I didnt ride for a while cus I ended up going down pretty hard, fast forward about a week and my bike wont start, the fuel pump wont prime and my starter wont go, so i think its my zener diode and go ahead and replace that, FI light turns on and starter works now, but still no fuel pump. awesome sauce.

I started following a post on here about what to do/fix/measure on your bike to find out why its not priming. Went through all 15 steps and it passed off of them, not so awesome sauce.

I find a thread about the same issue im having and so I start doing more measurements and going part to part (havent bought any parts yet)

Now this is the weird part, I cant short the diag port in between both light gray and black ecu plugs/ it wont flash my FI light it just stays on/solid.

Another problemo is my injectors get power when bike is OFF and once i flip the key the injectors get no power.


ignition-good(9.6v)
BAS-bypassed
KILLSWTICH-bypassed
Starter- good
battery-14v when charged
fuel pump primes when hotwired
all fuses are good
Relays-good
ECU seems good
Coils get power
No spark

im stuck.

 

Use my guide here and post actual numbers you measured at each step.

https://cbrforum.com/forum/f4i-main-...1-06-a-163487/

There's probably just ONE issue upstream somewhere and it's causing all your issues. Exact same blk/wht wire powers injectors, ECU, coils, pump, etc. If you're losing power to injectors when you turn key ON, then you're not getting power to ECU, pump, coils, etc. as well.

Doesn't matter one bit if pump primes or not if ECU's not getting power since it's ECU that turns on pump relay. Any amount of time spent looking at pump is complete waste. Gotta figure out why ECU's not getting power 1st.

Most important measurements are 6, 7, 8, 9 in guide.

 

After #9 measurement, we will find something is mis-configured with your engine-stop relay. The blk/wht power-output wire should ONLY have power with key ON/start-stop=RUN.

Somehow a power-wire is connected to it even when bike is OFF. What is puzzling is how power gets cut off when you turn key ON??? This cuts off power to injectors, and ECU, and fuel-pump and ignition-coils... Bike will never run like this...

Depending upon what you measure in #6, 7, 8, 9, we might be able to revert whatever jerry-rigging was done back to factory OEM configuration.

 

Battery volts- 14.1V
6- 24.1 Ohms (seems like a problem)
7- 12.8V
8- 12.8V
9a- 12.9V
9b- 12.9V

 

Now I get power to injectors when the bike is turned on... I have no clue why or how this doesnt make any sense to me, all I have done is mess with my BAS wiring harness. Ive opened it up and checked it out thats it. I dont understand how it has power, but still no fuel pump prime.

 

Also, when I was reading the diagram I kept tracing the ground from the gray plug up front all the way to wach diffrent turn it takes.

Fan motor switch- 0.01ohms
Service check connector- 4.3 ohms
stator grounds- 7.2 ohms
I know theres more grounds it connects to but I was just curious if thats wierd that ohms are different or not ONLY WHEN THE BIKE IS ON.

Perhaps it doesnt make a difference and im over thinking lol.

 

BAS is fine since it activates engine-stop relay and powers up EFI system.
It's ECU that primes pump by grounding pump-relay. It's not happy with something.
ECU might even be dead if it doesn't have any power to it.
Leave that for later, because there's other problems ahead of that.



First, let's verify your blk/wht power wire.

- trace blk/wht power away wire from engine-stop relay
- follow each branch to end-components, make sure wire is continuous, no exposed conductors, nothing else touches it

- measure voltage at ECU connector blk/wht power-wire, volts = ???
- measure voltage at each ignition-coil's blk/wht power-wire, volts1-4 = ???
- measure voltage at each injector's blk/wht power-wire, volts1-4 = ???
- measure voltage at exhaust solenoid valve, blk/wht wire, volts = ???

When you're measure voltage at these end-components, wiggle and shake harness in between. Does any of them drop out?

 

Grounds should be as low resistance as possible. And shouldn't change when you turn key on/off, unless it's ground that's triggered by ECU (we'll test those later)

Ground for BAS is still a little high. But appears to be sufficient to activate engine-stop relay. Can try cleaning up connectors between BAS & engine-stop relay, grn wire and chassis-ground to improve.

 

Pink wire at ECU connector is too high. Needs to be 9.0v or less. Replace ignition-switch diode with higher-drop unit.

 

Battery- 14.1V
ECU connector- 13.7V
Coils- all four- 13.6V
Injector- all four- 13.8V
I don't have a exhaust solenoid, I have clean air mod done to it.