[Pravin]

Hi all,

Newbie to the forum here. I have a CBR 250 EFI engine (ABS model) that I bought from a breaking yard (not sure of the year), so I could use it for a go kart. So, it's just the engine along with the ECU and wiring harness.

What's missing - Ignition Key barrel set, Instrument cluster, Pair control solenoid, Bank angle sensor, EVAP solenoids, ABS ECU

Problem - I've got no ignition pulse or Injector pulse. But, when I power the harness, I hear the fuel pump relay click for nearly 4 seconds, which I believe is for priming. I also hear the IACV making noise for a few seconds. All this gives me hope that the ECM is functioning as it should. There is 4V coming out of Vcc terminal of the ECM (Red/yellow wire)

I've tried quite a bit and now I'm at my wit's end. Any direction from you all would be of great help

Test method - I have put a test light in the place of the ignition coil. So, if there is a pulse, the test light would flicker. I have ensured that there is 12V on one terminal. The other wire Lg from ECM to Ignition coil should provide the ground pulse.

Work that I have done so far

• I have put a toggle switch in the place of the ignition key set
• I found a pink wire along with the ignition set of wires (Not shown in the wiring diagram I have). I read that it's the anti-theft system and it needs 9V to enable the ECM. I have done that using a 9v battery now, but still no spark. I saw that in a youtube video, where a guy does that on a CBR 600, and it worked. I tried the zener diode + 1Kohm resistor as well.
• I have shorted the clutch switch terminal wires G/O & G/R to simulate clutch lever is pressed, I guess.
• I'm unsure about the Bank angle sensor. I have a 3 wire plug (Vcc, Gnd, Out) for it on the harness. I have tried to send 0 to 4 V back to the ECM through Out terminal. Still no spark.
• I tried to see if I can get the fault indicator light to tell what code is on there, but connecting a test light between ECM terminal 18 (Wh/Bl wire) & ground, but I got no flashes there. Also tried the test light between pin 18 and battery positive (as I wasn't sure if the control of flashes was with ground or 12V). Still no flashes
• I checked the Crank position sensor output with just a multimeter, I can see changes in resistance value as the engine cranks, so I believe it's good.
• 
  

 

[Tamir]

I'm still not that good on motorcycle electricals, but here's my two penny:

• You can try to check if you get a dummy indication for the side stand switch (shorten the wires in the green connector).
• I don't know what is the right way to simulate the bank angle sensor, but it seems to me that you didn't give a good solution there either.
• So right now, as I understand it, you are in the stage of "cheating" the ECU, and only after you have settled into this stage properly you will it be possible to think about checking the classic troubleshooting scheme.

 

[Pravin]

I'm still not that good on motorcycle electricals, but here's my two penny:

• You can try to check if you get a dummy indication for the side stand switch (shorten the wires in the green connector).
• I don't know what is the right way to simulate the bank angle sensor, but it seems to me that you didn't give a good solution there either.
• So right now, as I understand it, you are in the stage of "cheating" the ECU, and only after you have settled into this stage properly you will it be possible to think about checking the classic troubleshooting scheme.

Hey Tamir, thanks for your inputs.

I can't find the side stand connector on the harness. Not sure if there was a model without that. The side stand switch is also in series with the clutch switch. I did complete the clutch circuit, and we have cranking.

Would the engine crank if the side stand was down?

You are right. I'm trying to cheat the ECU by simulating the conditions

 

[Tamir]

Would the engine crank if the side stand was down?

Yes and No.

• Yes if you are in neutral gear.
• No, if the gearbox is in one of the six gears. In this case, as you wrote, the two switches that are connected in serial should be pressed both: The side stand is up, and the clutch lever is pressed in. And only then the electric starter will work.

Therefore, when you are in N gear, no matter what indication is received from the side stand and clutch lever switches, the electric starter will work in any case and turn the crankshaft.

You are right. I'm trying to cheat the ECU by simulating the conditions

So you manage to turn on the electric starter. Now for the second matter, in my opinion you have not yet managed to "cheat" the ECU with the signal that should come from the bank angle sensor. I don't know what the correct signal is to get out of it, I know it's a safety accessory, so you might want to purchase it anyway.

 

[Tamir]

I can't find the side stand connector on the harness.

A green connector with two pins, which is located under the rubber boot along with three other semi-transparent connectors. Only him has two pins the others have three pins.
LINK TO PARTZILLA

 

[Pravin]

I see. OK, let me check that out regarding the side stand. I will also try with a bank angle sensor as suggested