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Hidden limiter or issue with map? Trigger errors for CAS?


M1tch
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Hi all,

Just need a bit of a hand with this one, just taken the car out to get some logging in with the new engine, currently dialling in the knock trim levels by cylinder. Think I have almost sorted out the VVTi trigger errors using the offset but still not perfect.

The issue I have just had is that under WOT at around 4,250 or 4,500 RPM I get what feels like a limiter or misfire, I can however push through but it will then do it again a few hundred RPMs later. If I 'sneak' up to the RPMs there doesn't seem to be this issue, last time I had an issue like this I found that there was a small amount of water in the plug holes causing a misfire - all plugs and coil packs are dry and have done about 100 miles so far.

I have attached my map and log file, it looks fairly subtle in the logs but you can just about see the slightly bumpy MAP reading in the screenshot.

Worth noting that:

  • I haven't changed the ignition timing since installing the new engine and has pulled cleanly before
  • AFRs are on target at 13:1
  • VVTi map hasn't been changed but I have set/started to correct the trigger offset
  • VVTi target vs actual shows that the VVTi is under control
  • Trigger cam test is off
  • Still working out knock trim levels so one cylinder might show higher than others at the moment
  • Dwell times on the coils haven't changed since updating them on the previous engine
  • The car is NA with a lower compression ratio than stock (currently 9.5:1 vs 10:1) ready for boost

I can only guess that its ignition breakup, limiter or perhaps knock? Although there is no spike in knock levels in the cylinders in the 4k RPM range.

Might look to perhaps use the basemap ignition table as a test to see if its ignition timing based but not had this issue before.

image.png

 

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I took a look, I would guess that it may be a fuel tune Issue. the map doesn't look very clean and, it can be very possible that bein N/A engine, you get a resonance at this RPM, giving a lean spot and leading to missfire.

I can see that at 4200 rpm there is always a lean spike (due to missfire, or giving a missfire, can't really know).

I would suggest disabling close loop fueling and taking some more time tuning the fuel map.

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29 minutes ago, dx4picco said:

I took a look, I would guess that it may be a fuel tune Issue. the map doesn't look very clean and, it can be very possible that bein N/A engine, you get a resonance at this RPM, giving a lean spot and leading to missfire.

I can see that at 4200 rpm there is always a lean spike (due to missfire, or giving a missfire, can't really know).

I would suggest disabling close loop fueling and taking some more time tuning the fuel map.

Thanks for that - I will look to get some more logging done, although I did briefly check the AFR gauge in the car and it was holding solid at 13:1 whilst around that area - the auto fuel wideband is also locked out at full load so its using the table as is with no corrections and its 0.2 AFR lean so not enough to cause it to stumble.

I have just noticed a huge spike in the coil dwell time - its meant to be at around 2.5ms which it is for most of it but it looks like its spiked up to almost 5ms - oddly the issue seems to happen just before this - battery voltage is still ok so it should be spiking up to that amount - should only be there at around 10v.

image.thumb.png.7abd62816c02d5af06e666c5dcb67ccd.png

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Can you do a triggerscope at around 4000RPM.

A spike in dwell is usually an indication of a trigger issue and you have 2 trigger errors saved in the log.  The Inlet cam still doesnt look completely happy either, so lets see what the triggerscope shows.

How to do triggerscope: https://1drv.ms/v/s!AiYbYlZQuRHPmidU5V2CmTcv6t2y?e=WMGPSW

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10 minutes ago, Adamw said:

Can you do a triggerscope at around 4000RPM.

A spike in dwell is usually an indication of a trigger issue and you have 2 trigger errors saved in the log.  The Inlet cam still doesnt look completely happy either, so lets see what the triggerscope shows.

How to do triggerscope: https://1drv.ms/v/s!AiYbYlZQuRHPmidU5V2CmTcv6t2y?e=WMGPSW

Thanks Adam, will have a go at this tomorrow - have been trying to sort out the issues with the VVTi trigger 2 issues and have gone through the trigger offset test a few times to try and dial in the correct offset - think originally it was at 50 degrees as default.

I will also perhaps switch over to the 2NZ-FE cam control mode to see if that sorts anything out as well as I know this sometimes helps - oddly there aren't any trigger 2 issues when the dwell time spikes, will try and tweak the offset slightly more as well, its far better than it was but still showing missing and extra pulses - its only got 3 teeth - 0 degree, 90 degree, 180 degree and a gap at where there would be one at 270 degree. 

image.png.755d93f8744d3c60a3e7c9507fd0689b.png

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12 hours ago, Adamw said:

Do the triggerscope first.  The VVT issue is likely related to your trigger issue.

Trigger Scope Log 2020-10-11 9;54;01 am.llg

Morning Adam, please find the trigger scope log I have just collected from the car - seems to be fairly clean?

Ah, would these small blips cause an issue, the peaks should be large enough though - trigger filtering is set as per instructions.

image.thumb.png.da1e3bd5eed8ab3c955346ef3804f61c.png

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2 hours ago, Adamw said:

So was that scope done at about 4000RPM?  

The scope was done at around 2k RPM - will need to find somewhere to drive to so that I can rev it up a bit as I don't want to annoy the neighbours.

I also found on the drive yesterday that if I crept up to 4-5k rpm on partial throttle there wasn't an issue, was only when at wide open.

I will still get a trigger scope log at 4k rpm but it won't be under load unless there is a way I can log a trigger scope over a period of time?

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2 hours ago, Adamw said:

So was that scope done at about 4000RPM?  

Here is a trigger scope at around 4k RPM - still seems to be fairly clean with perhaps a slight bit of noise around where the blank tooth is but nothing erratic. I can see that the spikes in the signals go from 0v up to around 11v (vs just up to around 4v when at lower RPMs) - arming thresholds for both are 3v.

Trigger Scope Log 2020-10-11 12;43;55 pm.llg

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9 hours ago, Adamw said:

I would say your arming thresholds are a bit borderline too high.  Try set like below.

Im not confident this is your misfire issue, but possibly the reason for the trigger error and VVT issue.

ErLrNZ6.png

Thanks Adam, I will dial the arming threshold down slightly - its setup as per help file but will see if it makes a difference, I can also try and use the 2NZ VVTi trigger mode as well to see if that sorts the VVTi trigger error. 

If this doesn't sort the misfire, what else should I look at? I can't see any reason for the ECU to suddenly spike up the coil dwell time as its only meant to be at around 2.5ms in the table.

 image.png.d7178b0209b243d3db61fdc2905d2396.png

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2 hours ago, M1tch said:

I can also try and use the 2NZ VVTi trigger mode as well to see if that sorts the VVTi trigger error. 

As far as I know the 2NZ and 1ZZ vvt modes are the same, only the triggermode is different.

 

2 hours ago, M1tch said:

I can't see any reason for the ECU to suddenly spike up the coil dwell time as its only meant to be at around 2.5ms in the table.

As above that is due to trigger error.  If the ecu gets a tooth event from the crank at a time that doesnt match the predicted crankshaft angle then the ecu either needs to stretch or shrink the dwell time to ensure the spark happens at the updated crank angle.  

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7 hours ago, Adamw said:

As far as I know the 2NZ and 1ZZ vvt modes are the same, only the triggermode is different.

 

As above that is due to trigger error.  If the ecu gets a tooth event from the crank at a time that doesnt match the predicted crankshaft angle then the ecu either needs to stretch or shrink the dwell time to ensure the spark happens at the updated crank angle.  

Ah I see - so the issue is still a trigger error issue and the ECU is the compensating for this error with the dwell time to fill in the gap.

I am going to go through my large number of previous logs to check to see if there are still issues with trigger errors so that I know what I am looking for.

I have checked the earths on the engine and they are all ok, might just look to get a replacement sensor to see if its a slightly damaged sensor that only has issues at higher RPMs.

It is quite odd though as this is the first time I had felt like a missfire or limiter but I still need to find out what is causing the error.

I will change over the dwell timings as you suggest and see what that does - I might also run another cam test to find the offset again and also recheck the base timing on the engine to ensure that everything is still as expected.

With regards to the cam test - is there a set RPM I should aim for or just wait until the angle settles down at a set amount?

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  • M1tch changed the title to Hidden limiter or issue with map? Trigger errors for CAS?

 

I have changed the arming threshold to 2v from 2,000 rpm+ as per your suggestion @Adamw and gone for another run, the issue seems to still be there with regards to trigger errors however they were less pronounced and the coil dwell time didn't spike massively high like last time which is a bit of a relief but its still holding back sometimes. 

Looking at one of the quick WOT pulls from 2,500rpm up to around 6,700 rpm there were 11 trigger errors, battery voltage does drop down to around 13.7v so thats still fine, coil dwell time bumped to around 2.5ms which is perfectly within limits.

Just checking the VVTi position vs target it seems that they are fairly close, however the trigger errors seem to be when the VVTI is in operation - it doesn't seem to be high or low positions, just any time its being used. I have done the cam test again and tweaked it from 46.5 degree offset to 47.2 degree offset when I got back from logging - unsure if this 0.7 degree difference will make much of a difference though.

I have attached the log and map used (offset was still at 46.5 degrees), will go back out again at some point with the tweaked offset but wasn't sure if there is anything else obvious.

I can also see that sometimes the VVTi position overshoots slightly very sporadically and lines up with the errors, its usually under control, I think I also changed over the cam control to the 2NZ rather than 1zz, might switch it back over and see if that makes a difference as well.

image.png.7d632aa0da53df7d1ce0382bf6abc314.png

 

image.png

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4 hours ago, M1tch said:

Looking at one of the quick WOT pulls from 2,500rpm up to around 6,700 rpm there were 11 trigger errors,

There are no signs of trigger errors in that log above.  Are you now talking about the Inlet LH error counter for the VVT?

 

Can you do a few more triggerscopes so we can see if one captures the cause of the missing pulse errror.  Do a couple at idle with cams at zero, and another couple at about 3000 with cams at 40 deg.

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9 hours ago, Adamw said:

There are no signs of trigger errors in that log above.  Are you now talking about the Inlet LH error counter for the VVT?

 

Can you do a few more triggerscopes so we can see if one captures the cause of the missing pulse errror.  Do a couple at idle with cams at zero, and another couple at about 3000 with cams at 40 deg.

Thanks for having a look - yeah was looking at the LH error counter for the VVT as I can see its still missing pulses etc, I will see if I get a chance to take the car out again today and get some trigger scopes for you. The issue being is that I only get missing trigger pulses when at WOT - am I able to log the trigger scope over time at all?

I might also look to pull some timing out of the tables and perhaps change back to a basemap to check to make sure its not something like knock in a single cylinder. I have knock control on but with with 0 ignition retard etc, still working out the trims but have noticed that I am getting some spikes in individual cylinders on some of the pulls but not others:

Example is here where although not perfect I can see that the cylinders are generally inline (need to adjust the gain on cylinder 3)

image.png.f9a1e4540697c97e85a69f1027ff9a34.png

Here however is another pull where I have some spikes in cylinder3 initially and then cylinder 4 - in this run the spike in knock on cylinder 3 corresponds with some missing pulses on the VVT trigger. Not sure if the missing pulses is causing the issue or if there is genuine knock happening which might then be causing the trigger errors.

image.png.0480042d3eb3126fc00782422665aaab.png

Think I am going to pull some timing out of it and take it for a spin when I get a chance - your fix on the trigger arming voltage seems to have sorted it out a bit though which is great!

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I have gone back out again and got 2 logs, the first run I basically adjusted the timing down a bit to make sure it wasn't something like knock etc, still had the issue, I then turned off VVT completely to see if it was the VVTi that was the issue or something else - the problem is still there and was quite bad. 

Hopefully the 2nd log will help to figure out the issue as in the screenshot below I am at 100% throttle but the revs won't increase higher than 5,300 or so, it feels like ignition cut which is why I thought it might be a limiter or something. Coil dwell time is at 2.5ms at this point - perhaps I have an issue with my dwell settings. 

Looking at the knock readings I am getting increases in cylinders 1 and 4 - perhaps the coils are overheating or something causing me to drop cylinders intermittently? I have heard that 1zz coils can be a bit temperamental 

I have attached the log for the 2nd run and the map used with VVTi off with the HUGE flat spot at around the 7:28 mark - could really do with some help trying to work this out as I am not sure what else there is - it doesn't seem to be VVTi related and its not like there is missing map there, the AFRs are basically bang on to target as well.

image.thumb.png.9c3d23e73ac950579aa14ffd820b8fdb.png

201020 tuned VVTI + Ignition change + offset no vvt.pclr log no vvt.llg

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I have just gone out again with a different dwell time table, here is the previous table:

image.png.a909db07c7906a506f273dc975459e8b.png

And here is the table I just drove - the issue is still there though:

image.png.105ef2ea40e6c4b366ce8ed1d6c492ed.png

On the last log I had another HUGE spike in dwell time again - voltage at this point was at 13.67v, I am going to go back to the original dwell time setting again I think, although at WOT just before it started to have the issue again dwell time was at around 2.3 vs around 2.5 on the previous settings. I have no trigger errors and the trigger counter is still at 0. Is there any way for the ECU to only use the settings on the tables and not spike up? Looking at things like battery voltage, the voltage is still good, dropping to around 13.8v at full load and higher RPMs - knock spiked on cylinder 1 so looks like it might have misfired or something.

image.thumb.png.bab4e4107a3718904d9f59c3ae6077e3.png

Worth noting that looking back at previous mapping files, here is the dwell time table I had been using a while back - perhaps the dwell times are slightly too aggressive on the current map causing the coils to become unstable? Dwell time at WOT and higher RPMs on the table below showed basically 2ms across the board.

image.png.0e0957c5488ebc1918ae60cc942e7cde.png

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As I have said numerous times if you have a significant spike in dwell then it is due to a trigger issue.  If the dwell spike is only once in a while but your misfire is there all the time then the two probably arent related - in some cases the trigger issue can just be due to the misfire.  

The misfire is nothing to do with VVT and VVT cant cause the trigger error.   The VVT errors can be caused by trigger error.

 

On 10/21/2020 at 9:13 AM, Adamw said:

Can you do a few more triggerscopes so we can see if one captures the cause of the missing pulse errror.  Do a couple at idle with cams at zero, and another couple at about 3000 with cams at 40 deg.

 

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10 hours ago, Adamw said:

As I have said numerous times if you have a significant spike in dwell then it is due to a trigger issue.  If the dwell spike is only once in a while but your misfire is there all the time then the two probably arent related - in some cases the trigger issue can just be due to the misfire.  

The misfire is nothing to do with VVT and VVT cant cause the trigger error.   The VVT errors can be caused by trigger error.

 

 

Sorry Adam, was trying to get as much logged and tried out last night before it got too dark - just wanted to check a few other things to rule them out but rule them out one at a time. 

I was only able to get one at idle (with 0 cam) yesterday from what you requested - will see if I can drive somewhere to capture a few more at higher RPMs after tweaking the map to give me a 40 degree cam at 3k rpm. I did find that when not under WOT but gradually revving up to the higher RPMs I didn't get a misfire/this issue.

Trigger Scope Log 2020-10-22 4;17;05 pm.llg

I am going to go through the engine either today or tomorrow (weather dependant!) and check all connectors on the ECU wiring and sensors, the engine has only recently been rebuilt so there might be a connector that is coming loose when the engine moves under load etc - or something odd like a loose CAS which gets slightly pushed away from the teeth when the crankcase pressure increases.

Will try and get a few more trigger scopes later though, might also ask the other half to come along whilst logging to then capture a trigger scope whilst the engine is having this issue as its only noticeable under WOT.

I did also notice this in the screenshot below which happened just before I had the dwell time spike - its the same as on the previous log as well but unsure if they are related as I can still see the speed data coming in.

image.png.63ff39286ed8d2cc18b359f1e4e3e139.png

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I have gone out and got many trigger scopes as requested @Adamw on idle the VVT was set to 0, for the other triggerscopes the VVT was set to 40.

I could tell that the engine wasn't happy as it wasn't easy to really hold the RPMs as I would creep up on the RPM, it would hold but then increase again - I could hear the same sort of issue as before and hopefully one or two of the trigger scopes has captured something of use!

Here are multiple trigger scopes at between 2.5k, 3.5k and around 4k - there was defiantly some issues at around 3.5k where it would stumble a bit:

Trigger Scope Log 2020-10-23 12;38;28 pm 2.5 3.llgTrigger Scope Log 2020-10-23 12;37;34 pm 3.5 2.llgTrigger Scope Log 2020-10-23 12;34;52 pm 4k.llgTrigger Scope Log 2020-10-23 12;34;52 pm 3.5 2.llgTrigger Scope Log 2020-10-23 12;34;12 pm 3.5.llgTrigger Scope Log 2020-10-23 12;34;12 pm 2.5.llgTrigger Scope Log 2020-10-23 12;34;12 pm 2.5 2.llgTrigger Scope Log 2020-10-23 12;32;13 pm idle.llgTrigger Scope Log 2020-10-23 12;31;26 pm idle.llgTrigger Scope Log 2020-10-23 12;31;07 pm idle.llg

Is there a way I can run the triggerscope for longer than the very brief sampling window? Do I need to press and hold or just press the capture button?

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I have just gone in and removed the battery from the car and checked all earths and wiring both inside the car and out, found a possible issue with what I believe is a signal interference suppressor which wasn't 100% tight on the stud (although still making contact) - will see if I can take the car out tomorrow to see if that has made any difference.

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Ok, unfortunately this may have been a bit of a case of me not being able to see the forrest through the trees, but I think I finally spotted the (obvious) problem tonight.  Please change the trigger mode (not VVT mode) to 2NZ.  Yours has the 36-2 crank wheel, our 1NZ mode is expecting 36-4 teeth.  

Note you will need to set/check the base timing again after changing the trigger mode.  The arming threshold tables may overwrite themsevles also so just check that they still have the same voltages that I suggested above after the change.

Edit: You may need to set the VVT offset again too.

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32 minutes ago, Adamw said:

Ok, unfortunately this may have been a bit of a case of me not being able to see the forrest through the trees, but I think I finally spotted the (obvious) problem tonight.  Please change the trigger mode (not VVT mode) to 2NZ.  Yours has the 36-2 crank wheel, our 1NZ mode is expecting 36-4 teeth.  

Note you will need to set/check the base timing again after changing the trigger mode.  The arming threshold tables may overwrite themsevles also so just check that they still have the same voltages that I suggested above after the change.

Edit: You may need to set the VVT offset again too.

Thank you so much Adam, I will swap over the trigger mode to 2NZ rather than 1ZZ as it was previously and see if that makes a difference - looks like the arming tables are still set to 2V above 2k rpm.

Will go and get my timing light out again and set/check the base timing, I did ensure that I painted up the crank pulley when I had the engine out to make checking the timing easier than before!

Shall I set the VVT offset to 50 degrees again as default or just leave it at the current setting? I guess no real harm as its not like its got an offset of 30 degrees or something! Will just go through the procedure again to set the offset.

Thanks again Adam!

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