Some trigger issues

[Sutkale]

Hi,

Have had some unsolved trigger issues for a long time in certain conditions but now thought to tackle the issue, since it somehow got a bit worse when I relocated the battery.

The symptoms are roughly as follows:

1) Revving the engine standstill, trigger error comes in at app. 7000 rpms, causing 10-15 errors -> rapid rpm ramp rate

2) First gear, trigger error comes in at app. 7500 rpms, causing 10-20 errors -> still rapid rpm ramp rate

3) Second gear, trigger error comes in at app. 8000 rpms, counting up to 10 errors -> slower rpm ramp rate

4) Third gear and higher, the engine can be revved up to 9500 rpms and no trigger errors if there´s grip available and rpm ramp rate isn´t that high.

Trigger mode is MultiTooth/Missing, Tooth count 60, Missing Teeth 2, Trigger 1 type Reluctor. Trigger 2 type is Optical / Hall. Reluctor sensor is Siemens 2 wire sensor.

Changing trigger 1 filtering higher will make the issue even worse and adjusting trigger arming threshold does not really help, using now 2,5 - 3 volts at higher rpms seems to be the best option so far.

It is obvious that rpm ramp rate has something to do with this since the things get worse when rpms rice fast. Any ideas how to get forward with the issue? Or is this a mechinal and related to trigger wheel shape especially to missing teeth shape?

Just got a cheap picoscope on my hands and thought to play a bit with it, if that would provide me some help and see how the signal behaves when the issue occurs. I don´t know if ECU´s own trigger scope is capable of recording signal on high revs?

I attached a screenshot from the signal taken by ECU´s own trigger scope when trigger is error free.

[Dave Kriedeman]

Hi,

trigger 1 signal looks lovely.

Trigger 2 however definitely has some issues.

Can you please explain how trigger 2 (hall effect) is setup as far as how is it mounted what is the sensor reading off, a cam lug/tooth a CAS etc, what air gap are you running.

What brand of sensor is it and what type of engine do you run.

Regards

Dave.

[Simon]

As you now have the tool to check if you could get a capture at higher RPM say around 5000.

We want to see what the tooth after the gap does.

In the shot you have given You can see a slightly bigger spike on the tooth after the gap. In some cases at high RPM this can get so big the signal does not make it back to 0 volts before the next tooth arrives.

Trigger 2 is sitting a bit above ground which could cause issues if it is actually the case.

[Sutkale]

Hi,

Dave:

Trigger 2 type: Optical / Hall, Trigger 2 Filtering: Level 1 (low), Trigger 2 Pullup: ON,f Trigger 2 Edge: Falling, Sync Mode: Cam Level. The engine is aluminium 2.0 litre Volvo 4 cyl engine fitted with Garret GTX4202R turbo. Cam sensor is DENSO and the outlook is similar to this one: http://www.autopartswarehouse.com/sku/O ... 00528.html.

I am under impression that there is not usually issues with Hall sensors, but I can be wrong for sure. Haven´t checked the distance between sensing tooth and sensor but will do this on coming days.

Simon:

I also noticed the high voltage peak after the missing teeth. I think the crux over here maybe the depth of the missing teeth since it is on the same level as the surface between the teeth (as what I remember) causing voltage spike on the first toot after missing teeth and hence ECU loosing the sync. Would it be beneficial to increase the air gap between sensor and flywheel teeth? That would lower the voltage spike? As a rule of thump increasing the air gap is good for sensor performance at high rpm but would cause some issues at cranking since the voltage provided by sensor is so low at that moment.

As the Trigger2, what do mean by "Trigger 2 is sitting a bit above ground"? Sorry for the language limitations.. ?

Gotta study the oscilloscope use first, then try to capture the signal.

[Dave Kriedeman]

Hi ,

if you look at the data in the top left corner of trigger 2 it shows minimum voltage = o.33 volts not o volts

Maximum voltage = 4.15 volts.

Also if you look at the scope trace you will see that the green line doesn't go all the way down to the + + + + LINE.

Regards

Dave.

[Sutkale]

Hi ,

if you look at the data in the top left corner of trigger 2 it shows minimum voltage = o.33 volts not o volts

Maximum voltage = 4.15 volts.

Also if you look at the scope trace you will see that the green line doesn't go all the way down to the + + + + LINE.

Regards

Dave.

Okay now I understood it. Any ideas what to do to get the voltage to zero level as it should?

Thanks!

[Dave Kriedeman]

I would start with checking all of your ECU earths and the vehicle and chassis grounds.

Do your ECU earths go to the engine block, is your engine block earthed correctly, all the ECU earths SHOULD be separated and grounded at different points.

Make sure that the trigger 2 wiring doesn't run near HT voltage sources like HT PLUG LEADS or COP or COP wiring etc.

The trigger 2 sensor itself could be faulty.

How have you setup the sensor in the software as far as pull up resistor turned on or off etc.

I have a customers engine at present with a mag reluctor sensor that is off it's head, it produces 7.5 volts at idle with a 3 - 4 mm air gap and generates voltages past 30 volts with rpm.

What brand MAG sensor are you using, are the tooth profiles perfect, is there any run out in the trigger wheel etc.

Regards

Dave.

[Sutkale]

Dave: Gotta check the ECU earthing issue, but there´s 2x50mm2 earthing cables between block and chassis.

Managed to capture a shot from the crank trigger at around 6500 - 7000 rpm, though no trigger errors at that very moment... :twisted:

First tooth after missing teeth seems to spike a bit but the voltage drops well below 0 anyway.

Gotta change spark plugs and check ECU earthings also and test the crank sensor with different air gaps as a next task. Still can´t understand why this issue is present only when the rpms rise quickly.

[Dave Kriedeman]

Hi Sutkale,

What type of engine is it.

What RPM is screen shot 1 of trigger 1 taken at, curious as it has a -4.15 volts to +4.15 volts peak to peak sine wave.

Compared to -11.12 volts to + 12.44 volts peak to peak sine wave on trigger 1 screen shot 2 taken at 6500- 7000rpm.

Also compare your peak to peak voltages for trigger 1 on screen shot 1 and 2 they vary in peak to peak voltages for each pulse, I don't believe this would be an issue and may have something to do with your changing of filter rates coupled with rpm change.

What trigger arming voltages are you using.

Regards

Dave.

[Sutkale]

Hi Sutkale,

What type of engine is it.

What RPM is screen shot 1 of trigger 1 taken at, curious as it has a -4.15 volts to +4.15 volts peak to peak sine wave.

Compared to -11.12 volts to + 12.44 volts peak to peak sine wave on trigger 1 screen shot 2 taken at 6500- 7000rpm.

Also compare your peak to peak voltages for trigger 1 on screen shot 1 and 2 they vary in peak to peak voltages for each pulse, I don't believe this would be an issue and may have something to do with your changing of filter rates coupled with rpm change.

What trigger arming voltages are you using.

Regards

Dave.

Dave,

That's 2 litre 4 cyl Volvo engine.

First shot is taken at 2000 rpms if I remember right, that explains lower voltage I guess. Trigger arming voltage at high rpms is now 3 volts and changing them higher does not really change anything for some reasons. Haven't tested that on higher loads though.

[xtra-racing]

What firmware are you using?

[Sutkale]

What firmware are you using?

The newest one: "5.1.0.2009 Firmware / iVTS". Actually I updated to the newest one and the issue got worse but I relocated the battery at the same time.

[Dave Kriedeman]

Hi,

have you set the arming volt to roughly half the actual trigger voltage.

I would use the pico scope to measure the actual trigger voltages and then set the arming table to roughly 50% of the measured voltage

With the battery in the boot, make sure you have a good chassis earth and also at the block.

Use ohms and volts to check your earths.

Make sure your ECU earths go to the engine block?

Regards

Dave

[Sutkale]

Hi Dave,

Hi,

Yes I have tried different setting on trigger voltage. According to my scopeshots, it is showing about 12 - 14 volts as a peak voltage so trigger voltage could be around 6 volts at high rpms. However, it works best at 2,5 volts for some reason? ECU is grounded to head not block though! ANy difference? Groundings everywhere shows pure 0 ohms measured between different grounding points. One thing that may have something to do with this, is the alternator. Just noticed that it propably sucks energy while engine is not running and keeps a whining sound.

Gonna try 10K ohm resistor in VE+ wire in next few days. I red from Motec and Megasquirt forums someone´s been able to fix a similar type of issue with that.

Okay too a scope capture yesterday and it shows a higher voltage peak after missing teeth than previous shots at higher rpms:

EDIT: Forum says "attachment quota has been reached"..? Cannot add the attachment.

[Sutkale]

Hi Dave,

Yes I have tried different setting on trigger voltage. According to my scopeshots, it is showing about 12 - 14 volts as a peak voltage so trigger voltage could be around 6 volts at high rpms. However, it works best at 2,5 volts for some reason? ECU is grounded to head not block though! ANy difference? Groundings everywhere shows pure 0 ohms measured between different grounding points. One thing that may have something to do with this, is the alternator. Just noticed that it propably sucks energy while engine is not running and keeps a whining sound.

Gonna try 10K ohm resistor in VE+ wire in next few days. I red from Motec and Megasquirt forums someone´s been able to fix a similar type of issue with that.

Okay too a scope capture yesterday and it shows a higher voltage peak after missing teeth than previous shots at higher rpms:

EDIT: Forum says "attachment quota has been reached"..? Cannot add the attachment.

[Dave Kriedeman]

Hi ,

I will see if Simon can reset your upload quota.

Regards

Dave.

[Sutkale]

Here´s a link to the scopeshot:

http://i87.photobucket.com/albums/k133/ ... 5ee539.jpg

[Sutkale]

The manual states the following in respect of the sync mode;

"Multi-tooth / Missing Requirements

· When the Trigger Mode is set to Multi-tooth / Missing the sync tooth edge must occur within a green 50% zone as shown in the image below.

· The sync tooth edge(s) must also NOT occur in the 'missing tooth gap' or within 30 degrees (crankshaft revolution) of the tooth after the gap."

What is actually the 50% zone above? Within 50 % calculated from the "centre" of crank revolution / between missing teet on crank?

[Simon]

In this case you want to avoid the sync edge changing close to the gap.

In the scope shot you are well clear. Im assuming you are using CAM level for the sync mode.

[Sutkale]

In this case you want to avoid the sync edge changing close to the gap.

In the scope shot you are well clear. Im assuming you are using CAM level for the sync mode.

I am using cam level for the sync mode, thanks for confirming.

[Dave Kriedeman]

Here´s a link to the scopeshot:

http://i87.photobucket.com/albums/k133/ ... 5ee539.jpg

Your trigger 2 scope trace seems to be a lot cleaner, even though not going fully to 0 volt it only drops to 0.33 volts, but the little interference spikes etc in the first trace have gone.

Did you get to check all of your earths, we are chasing as close to 0 ohms as possible and under 1 volt to be a good earth.

Can you also please post your PCL file.

Regards

Dave.

[Sutkale]

Your trigger 2 scope trace seems to be a lot cleaner, even though not going fully to 0 volt it only drops to 0.33 volts, but the little interference spikes etc in the first trace have gone.

Did you get to check all of your earths, we are chasing as close to 0 ohms as possible and under 1 volt to be a good earth.

Can you also please post your PCL file.

Regards

Dave.

I did go through all the earths and we´re seeing 0 ohms almost everywhere, so this can´t be a grounding issue, I guess... How low has the volts drop in Trigger 2? Haven´t done nothing to trigger 2 so far, being more interested in trigger 1 behaviour. As concerning the latter, I changed the OEM crank trigger cable (all the way from the sensor itself, which is app. 40 cm long) to a screened cable and that made the trigger 1 signal better looking. Gotta test that on the road how it goes.

Will send the pcl-file soo if the forum let me to upload files.

[Sutkale]

Here´s the pcl file:

Volvo_GarretGTX_2.pcl

[Sutkale]

and a screenshot from the logger while the error occurs, rpm spikes up to 65500 and injectors dumps heavily fuel to the engine and acts as an launch controller since boost increases while car is standstill.

[Dave Kriedeman]

Hi Sutkale,

just an observation, you are running individual fuel trim on 4 cylinders.

Cylinders 1 and 2 have 0% trim.

Cylinders 3 and 4 have 1% trim.

Cylinder 1 Y axis is set to MGP (MAP)

Cylinders 2,3 and 4 Y axis are set to TP MAIN.

I personally would have also run a smaller FUEL MASTER and achieved higher fuel table numbers.

Your fuel table numbers max out only in the 40 range, some say it doesn't matter but I like to have a larger number for what I believe leads to better injector control/operation especially when running large cc injectors.

4D Fuel Mode is set to ON/ ALWAYS ON, however the table is full of 0's so I take it you haven't tried to tune this due to your trigger error.

You have 4D fuel activated but no Dual Ignition or 4 or 5 D ignition tables setup.

Are you running a CDI unit as I notice your dwell table is set to a flat 1 ms.

The above will have no effect on your trigger 1 issue, these are just observations I have made, to be sure you are aware of them.

Looking at your trigger 1 arming threshold values they appear to be set far to low, I would raise the trigger arming voltages to at least half of the measured voltage at that given rpm, especially when dealing with what appears to be a very sensitive mag reluctor.

Also how big is the air gap between the tooth of the trigger wheel and your sensor and are all of the tooth profiles exactly the same.

Also by chance are you sharing the trigger 1 signal with the factory ECU or similar to make the Tacho work or BEM stay functioning, if so you may require a pull-up resistor.

Regards

Dave.