misfire at light load Gen I Hayabusa - FIXED

[LSR Racer]

Part throttle mis-fire that I thought was lambda related but now I'm thinking it is a mis-fire. It looks like there's a mis-fire that then causes the lambda to go lean. Or is it the other way around? This is steady state cruising down the road.

Where should I start looking for the ignition mis-fire?

[David Ferguson]

I certainly think those are ignition misfires -- you can see the RPM (and ignition advance) drop just before lambda spike. Is it possible your plugs are fouling running that rich at < 3% throttle? I would normally tune for closer to lambda 1.0 in that area. I see you short term trim is trying to remove fuel.

How did you tune the ignition timing? If you did it on a load-bearing dyno for MBT then you should be set. If not, what happens if you add a bit of timing in that area? My GSXR-1000 maps have 30 - 40 degrees advance at 3% throttle and 3500 RPM and rising rapidly to 65 deg @ 5000 RPM.

[LSR Racer]

After readying your comments, I pulled up a stock Gen I Hayabusa timing map from ECUEditor and confirmed, it has more timing everywhere than what I'm working with here. This M84 came off my Gen II racebike and I was tuned by someone else so I'm not sure if he used Max Base Torque but either way, this map has less timing like you said.

I copied the stock Hayabusa timing map into the MoTeC and I'll try that tonight.

At what throttle settings would you set Lambda target at 1.0? My part throttle cruise is always under 5% so I was going to use that but I truly don't know. Also, I'd like to sort out this misfire before getting fancy with the lambda.

Thanks for the tips!

[David Ferguson]

Please be careful just copying the entire timing map. Maybe you could just take some hints from what the low MAP / throttle sites and modify your map in steps.

If the CrIP is not absolutely correct, the tuner may have ended up building in corrections in the timing maps.

Personally, I would be targeting lambda 1.0 for anything less than 20 - 30% throttle.

Over at HP academy they have produced some webinars on target AFR/Lambda values. Not sure if you'll be able to see these, but I think you would find it useful:

https://www.hpacademy.com/previous-webi ... d-engines/

or if you are turbocharged...

https://www.hpacademy.com/previous-webi ... n-engines/

[LSR Racer]

Thank you, David.

The timing changes helped power in the lower ranges but the misfire is still there at part throttle cruise so I'm thinking it is something else. I still don't understand why a mis-fire would cause the lambda to go lean.

Since the mis-fire is in the range of 2-8% TPS, I am looking at the MAP sensor. It looks like my ECU config already had a custom MAP sensor entered from when it was tuned on my Gen II bike. Now it is on my Gen I with stock MAP sensor. I didn't see a "Denso" option which is what my stock Gen I MAP sensor is. I'm going to google around for a calibration table for that or ask around and see if one of the Delco 100Kpa sensor configs would work as a suitable replacement.

While I work on that, I'll get on to verifying the CrIP setting of 455 is correct. From watching the webinars, it looks like I should get the engine started with a timing light on #1 cylinder and the TDC mark (throttle side of motor, access port) and check for alignment when I enable "Test Advance" in the Crank Index Position" adjustment window.

[David Ferguson]

When the engine mis-fires there is no combustion, so the Lambda Sensor detects the oxygen that wasn't consumed and that shows up as a lean spike.

I have the stock GSXR 1000 MAP sensor calibration as 1.2V = 20 kPa and 3.96V = 112 kPa. I've also seen a calibration that is 0.5V = 0 kPa. and 3.6 = 100 kPa, which is very close to the same. Hope that helps.

[LSR Racer]

It was me. I had a wire on my TPS that should not have been there.

[LSR Racer]

I had a wire running to a gauge that would allow me to see my TPS while riding and I was using this to help me tune. After the third person told me to re-check the TPS, I removed the wire and it all works now. Now onto the next thing!

[LSR Racer]

Hi David,

Would you recommend the HP Academy for this type of learning? I was considering taking their starter package.

Thanks!
Shane

Please be careful just copying the entire timing map. Maybe you could just take some hints from what the low MAP / throttle sites and modify your map in steps.

If the CrIP is not absolutely correct, the tuner may have ended up building in corrections in the timing maps.

Personally, I would be targeting lambda 1.0 for anything less than 20 - 30% throttle.

Over at HP academy they have produced some webinars on target AFR/Lambda values. Not sure if you'll be able to see these, but I think you would find it useful:

https://www.hpacademy.com/previous-webi ... d-engines/

or if you are turbocharged...

https://www.hpacademy.com/previous-webi ... n-engines/

[greenamex2]

I am a customer of HPA's, highly recommend them.

The support forum is pretty good as well (and some familiar faces pop up on it regularly).