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NGTRX trigger issue


Clipto2000
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hey guys,

 

I had this issue back in May. took the car off the road to get everything look and replace anything that needed to be done.

 

got told the wiring and sensors for the trigger kit were in good condition and the grounds were also good. They did find the crank sensor needed to be regapped.

 

this was my last post about it.

https://forums.linkecu.com/topic/16093-random-power-cut-while-driving/

 

warmed the car up this morning took it for a drive around the block all was fine until I pulled back into the driveway and it started to fault. have attached the following trigger scope pictures are from when its faulting, log and tune file.

 

 

 

trigger scope 1.jpg

trigger scope 2.jpg

trigger scope 3.jpg

Isaac GTR.pclx trigger issue.zip

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Ok sweet, you have caught the problem well in these scopes so it gives us something to investigate.  It wasnt captured in the scopes in your previous linked post (assuming it is the same issue).

The problem is actually trig 1 there are patches there where it is not coming all the way down to zero volts, (the signal needs to drop below 1.0V to be considered a tooth).  I have since learnt that the "extreme noise" on trig 2 is actually caused by the low resolution recording the scope does in some specific modes, so that is nothing to worry about.  

Example here:

Ow9AXPu.png  

 

I will explain how the trigger input & sensor works to give you a feel for where to look.  The ecu has a "pull-up resistor" internally which applies a low current voltage to the trigger circuit (about 3.5V).  So if there is nothing connected to the input we will see ~3.5V in the scope.  When a tooth goes past the end of the sensor there is effectively a switch inside which connects the trigger input to ground - so it should go down to near zero volts (a ~.5V offset is not unusual).  

So in those areas where the signal doesnt come all the way down to ~0V, this means the trigger input is not being connected to ground properly - this could be the "switch" inside the sensor failing, or it could be a loose connection somewhere.  

Im assuming that both the cam and crank sensor connect to a common ground at the front of the engine somewhere.  Since we dont see any voltage issue on the cam sensor in the same areas of the scope, we can assume that the ground is ok up to at least the point where it splits off to the two sensors. 

With it idling I would jiggle/yank/bend all the crank sensor wiring and connectors etc to see if that causes a stall or big error.  If not then I would next try replacing the sensor.  Im assuming it is the red M12 threaded one? They are generally pretty reliable but since they are only about $80 it is worth replacing to eliminate.   If it is the red one then the part number you are looking for is GS100502.

 

 

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