Random misfire high load - fresh build, same issue

[foes]

Hey guys,

Strange issue with a G4+ 

Turbocharged engine running ethanol fuel, having a strange "misfire" at almost exactly 5.5k RPM - however the issue is intermittent. Sometimes it pulls clean every 5 or 6 pulls, however most pulls it has the exact same issue, it stumbles and loses power - not a complete cut but a slight misfire. Similar to what I'd expect from plug gap but I've tried plugs at all sorts of gaps. Only running 0.6b boost I'd say gap isn't really an issue.

Any help would be greatly appreciated. The same setup had the same issue previously at 11 psi boost but when I would back it down to 10PSi it was fine. I don't think its boost related as we're now at much lower pressure but just seems like a coincidence 

I've attatched some tune files and logs showing the issue, however the logs look clean with no evident misfire. 

Wont let me upload all logs due to size.

Setup is as follows

1G-FE VVTi

AltezzaLink ECU - running 1JZ VVTi trigger

Standard Coils (Same as yaris)

550cc oem reflowed injectors

E85 Fuel

BKR7E NGK Plugs

Many Safetys removed.pclr AJ Break up 9psi.pclr

https://drive.google.com/file/d/1EaDck8Ow7DaSvVORxvgvYotas7ZXM98f/view?usp=sharing

 

https://drive.google.com/file/d/1zhiU5OaxZPXJYhajVlvkgwwWE92sB4_8/view?usp=sharing

[0x33]

To me you have a few weird things on the log that I'd look into further. 

a) If lambda measurement is correct then you are a decent amount leaner than your target coming onto boost. On E85 you may need to richen it up some more to keep things from wanting to misfire. 

b)

 

Your dwell time seems to go all over place during said misfire. Maybe a Link engineer can confirm, but I'd imagine this is due to an RPM fluctuation or momentary loss of triggering position thats not being picked up on 40HZ pc logging. I have seen something similar before from a faulty CAM sensor. I doubt you have a crank/cam sensor issue but it does bring me onto the last point

c)

For a factory toyota setup these arming thresholds seem a bit optimistic and I've seen misfires caused by these being really out of whack. Unless you have done this already then use the triggerscope to scope each RPM breakpoint and enter in new values for the threshold. Theres a guide on this in the helpguide in the software if you arent sure. 

Also your VVT has not been setup properly. Might be an idea to set that up and get it configured properly

[foes]

7 minutes ago, 0x33 said:

To me you have a few weird things on the log that I'd look into further. 

a) If lambda measurement is correct then you are a decent amount leaner than your target coming onto boost. On E85 you may need to richen it up some more to keep things from wanting to misfire. 

b)

 

Your dwell time seems to go all over place during said misfire. Maybe a Link engineer can confirm, but I'd imagine this is due to an RPM fluctuation or momentary loss of triggering position thats not being picked up on 40HZ pc logging. I have seen something similar before from a faulty CAM sensor. I doubt you have a crank/cam sensor issue but it does bring me onto the last point

c)

For a factory toyota setup these arming thresholds seem a bit optimistic and I've seen misfires caused by these being really out of whack. Unless you have done this already then use the triggerscope to scope each RPM breakpoint and enter in new values for the threshold. Theres a guide on this in the helpguide in the software if you arent sure. 

Also your VVT has not been setup properly. Might be an idea to set that up and get it configured properly

Thanks so much for the reply mate!

 

a) I've sorted that out, fresh motor and just dialling in the old tune from the previous motor, I've added some fuel in boost now so all happy there. Didnt really fix my issue.

b) I glanced over that in the logs, definitely something to confirm. But I couldn't see any cuts or sync loss as a result. Coils and plugs are brand new for what its worth. Cam sensor was faulty previously so we also changed that out for a good unit.

c) I'll sort out the arming table, didnt actually think about that - although timing being out a couple degrees shouldnt cause a misfire like this afaik

d) Haven't looked at VVT yet, have you got any suggested settings? I'd assuming 2JZ/1JZ VVTi should translate

[foes]

Upon closer inspection the dwell looks fine - the misfire is at 5500RPM - dwell looks clean there. Am I missing something?

 

[foes]

On 7/9/2023 at 11:54 PM, 0x33 said:

To me you have a few weird things on the log that I'd look into further. 

a) If lambda measurement is correct then you are a decent amount leaner than your target coming onto boost. On E85 you may need to richen it up some more to keep things from wanting to misfire. 

b)

 

Your dwell time seems to go all over place during said misfire. Maybe a Link engineer can confirm, but I'd imagine this is due to an RPM fluctuation or momentary loss of triggering position thats not being picked up on 40HZ pc logging. I have seen something similar before from a faulty CAM sensor. I doubt you have a crank/cam sensor issue but it does bring me onto the last point

c)

For a factory toyota setup these arming thresholds seem a bit optimistic and I've seen misfires caused by these being really out of whack. Unless you have done this already then use the triggerscope to scope each RPM breakpoint and enter in new values for the threshold. Theres a guide on this in the helpguide in the software if you arent sure. 

Also your VVT has not been setup properly. Might be an idea to set that up and get it configured properly

Do you see any other issues? I could try log again but im not sure if I can increase the refresh rate

[Adamw]

The dwell scatter is a trigger issue, most likely related to the arming threshold being too high, but in both places that occurred in your log it was around ~3600/3800RPM, so probably not the cause of your 5500RPM issue.  

Can you do a trigger scope at idle and another at 3000.   

You have a log named "Break up and clean pull back to back", but in it there are only 2 pulls to about 4000RPM and one to 5900RPM, which one was the good one and which one was the problem one?

In the other log "General driving and pull with break up" where did the issue occur?

From the look of your injector PW curve, your peak torque is right about 5500RPM, so it could well be just not enough ignition energy for a rich ethanol mixture at high cyl pressure.  29deg Ign advance at 160Kpa and peak torque RPM seems a bit extreme, if you remove say 10deg advance from a few cells around this area does it still misfire?  

[foes]

54 minutes ago, Adamw said:

The dwell scatter is a trigger issue, most likely related to the arming threshold being too high, but in both places that occurred in your log it was around ~3600/3800RPM, so probably not the cause of your 5500RPM issue.  

Can you do a trigger scope at idle and another at 3000.   

You have a log named "Break up and clean pull back to back", but in it there are only 2 pulls to about 4000RPM and one to 5900RPM, which one was the good one and which one was the problem one?

In the other log "General driving and pull with break up" where did the issue occur?

From the look of your injector PW curve, your peak torque is right about 5500RPM, so it could well be just not enough ignition energy for a rich ethanol mixture at high cyl pressure.  29deg Ign advance at 160Kpa and peak torque RPM seems a bit extreme, if you remove say 10deg advance from a few cells around this area does it still misfire?  

I'll do some more logging this afternoon

Clean pull back to back breaks up in the pull that goes to 5900

The break up in the other log is towards the end where you see the 99% TPS

 

I've tried bringing the timing back in those areas and it still had the same issues. The coils should have enough energy as I've pushed them further in other cars.

[foes]

On 7/12/2023 at 2:06 PM, Adamw said:

The dwell scatter is a trigger issue, most likely related to the arming threshold being too high, but in both places that occurred in your log it was around ~3600/3800RPM, so probably not the cause of your 5500RPM issue.  

Can you do a trigger scope at idle and another at 3000.   

You have a log named "Break up and clean pull back to back", but in it there are only 2 pulls to about 4000RPM and one to 5900RPM, which one was the good one and which one was the problem one?

In the other log "General driving and pull with break up" where did the issue occur?

From the look of your injector PW curve, your peak torque is right about 5500RPM, so it could well be just not enough ignition energy for a rich ethanol mixture at high cyl pressure.  29deg Ign advance at 160Kpa and peak torque RPM seems a bit extreme, if you remove say 10deg advance from a few cells around this area does it still misfire?  

Heres some trigger logs at idle and 3k

925RPM AJ.llg 3000RPM AJ.llg

Removing 10 degrees just has it misfire even worse, such a strange issue

I also tried enabling VVTi but I just cant get the table to activate even though its selected, after deselecting and reselecting it like 10 times it eventually came up and I could see the cells activating but VVTi just wouldnt show any change.

[Adamw]

Both your cam and crank sensors are wired back to front.  You need to swap the +/- pins and the sensor plugs, then reset base timing.  

For the VVT, turn off aux 2, turn it back on, when it pops up with the message asking if you want to set default axes etc you must choose yes.  You then need to do the cam angle test to set the VVT offset correctly.

[foes]

3 hours ago, Adamw said:

Both your cam and crank sensors are wired back to front.  You need to swap the +/- pins and the sensor plugs, then reset base timing.  

For the VVT, turn off aux 2, turn it back on, when it pops up with the message asking if you want to set default axes etc you must choose yes.  You then need to do the cam angle test to set the VVT offset correctly.

Alright I'll give that a go. 

 

What in the scope shows the sensors being wired wrong? The trigger edge?

 

[foes]

4 hours ago, Adamw said:

Both your cam and crank sensors are wired back to front.  You need to swap the +/- pins and the sensor plugs, then reset base timing.  

For the VVT, turn off aux 2, turn it back on, when it pops up with the message asking if you want to set default axes etc you must choose yes.  You then need to do the cam angle test to set the VVT offset correctly.

 

I read this thread, has awesome info about this exact issue if anyone is searching.

 

Thanks so much I think that will be my issue - will try it tomorrow