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Trig1 err count and fuel cut


Rich52
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Hi

I'm chasing a very intermittant fuel cut which looks like its caused by RPM limit. I've found the Trig1 err Count paramater that also increases by 2 at this same point. It also increments at other times but most of the time it doesnt cause RPM Limit & Fuel cut . The max RPM recorded seems pretty consistant at 3xRPM at about 14500 rpm, ie a real 4850rpm. My logging is limited to about 100ms and since events are less than this its hard to capture.

Is there any other diagnostic that might suggest whether its is the crank or cam sensor that is the problem? Or could something else cause it?

My old ViPec doesnt have TriggerScope however I have put an oscilloscope on both signals and they look good, not noisy and no common edge transistions. However this issue only happens maybe once or twice a day when on a track day so again hard to capture.

I'm using Mitsubishi EVO 1-6 mode.

BTW another question, the RPM Limit count seems to equal the cumulative Trig1 err Count rather than the RPM limit fuel cuts I get - is that the case?

Thanks

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Can you attach some pics of the oscilloscope captures.  Make sure it has resistor sparkplugs evo's get bad trigger errors with non-resistor plugs.  

 

15 minutes ago, Rich52 said:

BTW another question, the RPM Limit count seems to equal the cumulative Trig1 err Count rather than the RPM limit fuel cuts I get - is that the case?

No the RPM limit count should increment everytime the RPM limit status goes active.  This will likely co-incide with trigger errors as the error will create an artificially high RPM, but it should increment whenever you reach the normal limit as well.

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Hi Adam

Thanks for suggestions. I've never come across resister plugs on an EVO but I'll investigate. My garage guru has suggested changing the CAM sensor that are known to be problematic with my symptoms so I'll try that.

In the mean time here is a plot of crank (top) and cam sensors at about 5k rpm.

image.png.5c0c72832a1ff14c53a508962796ce10.png

Cheers

Rich

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That is not a Evo 1-6 trigger pattern you show on your scope there. The Evo 1-6 trigger 2 signal has 1 tooth that is high for about twice as long as the other, yours are both the same length.  It looks more like you have a Evo7-9 pattern.

Evo 1-6:

Gy4S3ei.png

 

Evo 7-9:

UeFSdY3.png

 

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Interesting, it is indeed an EVO7. It's always been mapped that way by an experienced mapper! What effect will that have and is it simply a case of changing the mode setting or would it need a complete remap for timing etc.

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Thanks Adam. Given its been working for a long time like that what would advantages be of changing? (ie better accuracy/stability/noise tolerance etc). Could this be cause of Trig Errors I've seen?

I see the "Filter level" is set to 2, I couldn't find any details of the what the levels actually do so hard to know what interaction this might have too.

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  • 1 year later...

Hi Adam

An update on this. I recently had my tuner change to the correct Evo 7-9 pattern.  However having run it for a while I am still seeing occasional errors that sometimes result in a ignition cut. To give you an idea the ECU stat has counted about 70 errors over 3 track days but a noticable cut has probably only happened 4 or 5 times.

The sensors are quite new and my tuner looked at the crank sensor wheel and said it looked OK too.

Any other ideas please?

Thanks

Rich

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Posted (edited)

Thanks Adam.

I didnt think I had a log file showing errors but looking back I have found one that is attached. There are two Trig Err events taking total to 6 in this log. The second one where count goes to 6 corresponds to a fuel cut event. I also see that the Idle Target Error goes to -1000 for a period of time which is a bit odd?? However the rpm logged looks OK. Can you see anything else to give a clue?

I should also add that is was before we changed to the "correct" trig mode for my Evo 7.

On resister plugs these are not recomended by my tuner so not an option to try really.

Log 8-06-20 12;20;30 pm Donington Laps.zip

Edited by Rich52
Found a log file
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2 hours ago, Rich52 said:

On resister plugs these are not recomended by my tuner so not an option to try really.

You absolutely must run resistor plugs on an evo if you are running wasted spark ignition.  Even the stock ecu will barely drive with non-resistor spark plugs.  

 

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Strong advice! However I've never run resistor plugs and never had mis-fire problems so what is the benefit and how does it relate to my core issue? I'm running 580BHP so less spark from a resistor plug is not ideal!

Did you manage to check out the log file - anything interesting? Thanks

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Sorry to add another query on a slightly(!) different topic. Is it possible to get details of the CANBUS hardware mod needed for pre 10000 s/n V44 (mine is 4963). I'm an Electronics Engr so very happy to do it myself. Was thinking this would give me an option for long term logging as well as extra dash data.

Many thanks
Rich

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Resistor plugs do not give you significantly less ignition energy as the spark plug gap has almost infinite resistance compared to the resistor.  The spark current is reduced a little which increases the spark duration - the coil still has to "discharge" the same amount of energy (you lose a tiny bit as heat in the resistor).  The resistors attenuate electromagnetic interference, without them you will have random voltages conducted and induced into all the electrical circuits that are near the ignition system - the most common noticable result is trigger error or USB comms issues.

 

 

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I use NGK Spark Plugs Iridium IX BR8EIX type 5044. Having dug around I've seen these advertised as "5k resistor" plugs so maybe I'm flat wrong on this. Certainly not routinely called resistor plugs here abouts :) - are these type what you are referring too?

ps any chance of CAN BUS mod details for my pre s/n 10k V44?

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