Dear all,

Please help me if anyone know this symptom.
I'm having no luck starting my bike and today I pulled out the fuel injectors while all 4 of them are still attached with the fuel rail to see how they are spraying while I push the starter button. And I realized that all 4 valves opens as soon as I push the button but never close unless I release the button.
I looked up on the internet for the duration of the opening time of conventional injector and found out it is about 1ms~10ms.
Does anyone know if this symptoms is common thing? or does anyone know if this is a crucial symptom of FI computer failure?

Thanks in advance

Kentaro

I think it's a feature of the Motronic that pressing the starter button enriches the mixture - i.e. the injectors will spray fuel whilst it is pressed.

There are some really good troubleshooting guides on this forum.

chris846 wrote:I think it's a feature of the Motronic that pressing the starter button enriches the mixture - i.e. the injectors will spray fuel whilst it is pressed.

There are some really good troubleshooting guides on this forum.

Thanks for the quick reply Chris846,so it was just behaving as it was intended to be..
When I pulled out the 4 injectors with the fuel rail today  to see how they spray,As soon as I pressed the starter button ,the engine spinned for the 1st time after I finish bulding it so I thought the fuel was too thick all the time I was trying to start for the past couple of weeks.
I will do more research here. 
Thanks a lot!

Kentaro

I have checked the current at pin #12 which I assume it should send the signals intermittently to open and the shut the FI but when I checked, it was continuous current while FI relay was on. Is this suppose to behave like this? 
Also, the current while starter is running at pin#1,It was 55mv which should be in between10-20mv according to the trouble shooting.(#1 was the only pin it did not match with the given chart)
I have very poor knowledge about electrical stuff but I'm using m.unit to source the power to the both ICU and FCU.
Im using m.unit and now I'm assuming this is causing both ICU and FCU to draw too much amp since I took out the stock fuse box.
Can anyone give me a tip if my aim is correct?

Thanks in advance.

Kentaro

Sounds like your injectors are working ok.
When you turn the ignition on the pump will run to pressurize the fuel rail.
When you press the starter button the motor starts to turn over and the injectors fire. Assuming the motor doesn't start in this case, when you take your finger off the starter button and the motor stops turning over, the injectors stop firing.

The K100 fuel system is multi-point injection which means the four injectors all fire at the same time... so it may look like they are all spraying continuously but because the dwell time is very short its difficult to decern.

The no-start issue may be due to a temp sensor problem. That's easy to test on FICU plug pins #10 and #13. You can find the data on the Forum Tech Page. It may have an earthing issue which means the FICU will be grossly over-fuelling on start-up.
Another possibility is the ignition. Check that the ICU plug is secure and the rubber cover is in place. Also check that you're getting spark.

Just so you know.... your '87 2v has an L-Jetronic system not Motronic and pressing the starter while the motor is running does not enrich the fuel mix. That's a myth.

If you've modified the system electrics you may have a bigger problem.
Good luck

Holister wrote:Sounds like your injectors are working ok.
When you turn the ignition on the pump will run to pressurize the fuel rail.
When you press the starter button the motor starts to turn over and the injectors fire. Assuming the motor doesn't start in this case, when you take your finger off the starter button and the motor stops turning over, the injectors stop firing.

The K100 fuel system is multi-point injection which means the four injectors all fire at the same time... so it may look like they are all spraying continuously but because the dwell time is very short its difficult to decern.

The no-start issue may be due to a temp sensor problem. That's easy to test on FICU plug pins #10 and #13. You can find the data on the Forum Tech Page. It may have an earthing issue which means the FICU will be grossly over-fuelling on start-up.
Another possibility is the ignition. Check that the ICU plug is secure and the rubber cover is in place. Also check that you're getting spark.

Just so you know.... your '87 2v has an L-Jetronic system not Motronic and pressing the starter while the motor is running does not enrich the fuel mix. That's a myth.

If you've modified the system electrics you may have a bigger problem.
Good luck

Thanks Holister,

After I read your message, I have checked the FICU according to the trouble shooting again and I went out to look for a LED bulb to check if the signal at the Fuel injectors are sent intermittently. there I found out that the fault was came from bad earthing of FICU.
With my pity knowledge of electric, i used stainless bolt to place FICU and that was causing the injectors to keep opening.
After I found that out, it fired right up without hesitation, with no backfire. I tested and calibrate it during the week end and now it is ready for the inspection.

Thanks again for sharing your kind insight.

Warm regards,

Kentaro