Engine Kick EVO X 3 to 3.5k

[tricky1024]

cheers for the links: https://file.io/wKrBpJIbZtkH

[stevieturbo]

I'm assuming the stab throttle is where some of these events were happening ?

Really nothing is sticking out.

I'd say again though, confirm base timing is setup and correct

And have you tried say pulling 10 deg out of the whole map to see if it changes anything ? Just some sort of large sweeping change for a quick test.

Although there are some odd wobbles in rpm for example at 14:01:28.336

Do you think these little wobbles would correspond with anything ?

[tricky1024]

Yes, the quick stab is where i am seeing the judder.

base time was set on the new engine builders on the engine dyno, i will need to get a scope to check it. i dont think its that though but agree the double check will not hurt.

i will try taking 10 degrees out in that area, that is a good test, i did see fuelling goes rich a little between 2k and 3.5 and low map so i have removed a little there. i will also disable the vvt again for the test

as for those wobbles, not sure, dont normally feel anything that low. so at 2200rpm and 400 map we are at 36.56 degrees timing at 2650 same map the timing increased to 40 degrees, maybe remains at 40 to max rpm (at low load), i have checked the 40 degrees with the standard engine ecu map and its right.

It sounds like a misfire in the exhaust, i mean you can hear it and feel it.

[stevieturbo]

Whilst fueling is moving about a fair bit, I'd doubt that is anything to do with it.

Throughout as well, you seem to have a very active fuel cut, but you are not logging the reason for the cut, trqfuelsevsrc etc

It might be the over-run fuel cut, or it might be something else.

I'd try setting it to an rpm where it will not be active and logging all cuts properly just in case randomly one of them is becoming active.

[tricky1024]

so reporting back from last night, took 10 degrees out, no difference, issue remains, i will take a look at the cuts today.

[tricky1024]

ok, ive done a lot of testing and digging.
still cannot shift the issue, i found some issues in the vvt tables but for testing unplugged the vvt valves. issue remains, found ignition trim table with some figures for a single cylinder, removed these, took a log with the car not moving as you can hear the pops even just on the spot not moving, here is a log holding at 3ish k, the fuelling seems to be all over the place, is this anything to worry about?.

anyone fancy looking at the calibration to see if they can see anything i and the tuners cant?

[stevieturbo]

Some of the large swings in fuel pulse width, seem to be related to your battery voltage dropping sharply.

This would suggest perhaps injector dead times are not correct. Of course you'd want to know why your battery voltage is so unstable.

And then of course there is a reaction from closed loop trying to change things.

For now, I'd turn all closed loop corrections off whilst hunting the problem, and stabilise fuel tuning in your 3k area manually.

And find out why battery voltage is changing so much, and also whether any dead times entered, are correct for your injectors and pressure.

As the problem seems to be very repeatable, getting an oscilloscope trace of the primary or secondary ignition would be helpful to see if it shows anything
I'd also like a scope trace of the crank/cam triggers too, synced with cyl1 ignition event to see if it highlights anything irregular during a miss.

I guess you could also try with the alternator disconnected. You wont want battery voltage low, but at least it will be stable for a brief test.

And just before the 3krpm...

You seem to be around 23-2800rpm, very high ignition timing values in ignition base, yet idle control is active, but idle is not dropping ?? Seems very strange. why have idle control active so high nowhere near idle ?

[tricky1024]

good spot indeed.

i will investigate now a little further, i have no issues unplugging the alternator, its a smart alternator and feeds back to the ecu. i am not 100% sure on how any of that works but for now you have given me a really good areas to continue hunting this down.

as always thank you for your time and advice.

[stevieturbo]

should amend that to say the swings in Lambda/AFR are due to the battery voltage changing which affects the battery compensations for the injector, which sees swings in fuel injector pulse width

Try logging whatever alternator control parameters you are using to see if the droppages are a result of control, or something random and uncontrolled

[tricky1024]

ok some progress at last, if i turn Lambda off i have stable battery and fuelling, i have updated the injector charge times from injector dynamics for the 1300's (yes im aware the fuelling will change but i will check fuelling when i am sure its all ok), also reduced battery voltage from alternator to 13.8, so far no juddering at all.

as soon as i re-enable the lambda im get the judder back but interesting as i enabled whilst the car is running i get voltage spikes now at 1.8k, looks like it could be the lambda heater causing the voltage spikes? spikes are 30 to 35ms apart, constant.

question now, is it normal to have these spikes?, im guess not, if so what could be the cause, i would think possible earth issue but would that not effect all sensors etc?