No RPM when cranking

[swi]

Hi guys

I'm new to aftermarket ECUs and tuning. I have a built ej20 motor in my Impreza running on a plugin V1/V2 G4+. I'm using cams and gears from an ej208 (twin turbo) with the 20g crank sprocket I think . So I know the pickup/triggers differ between the models.

 

Currently im  not able to get it started, I did the trigger scope (on a few occasions it seems as though its skipping the Cam trigger, see below), I had also checked both at the ecu with an oscilloscope, individually because I only had 1 lead present. 

I did injectors and ignition coils test also and they are good but of course NO spark when cranking.

When cranking the triggers say yes on both 1 and 2 but the RPM signal remains at 0. I believe the Tacho switches to yes also.

 

Could I be missing something in the set up?

 

GREEn car gc8 camshaft waveform 2020.04.22.psdata

GREEn car gc8 crankshaft waveform 2020.04.22 2.psdata

[Vaughan]

So crank sprocket from an 89-93 legacy and cams + gears from an 01-03 legacy? are the cams AVCS ones?

The subaru v1-6 is a very specific trigger pattern and I don't think it will work with different cam signals.

it also looks like your reluctor sensors are wired backwards

[swi]

Thanks for the quick reply Vaughan,

Basically, legacy or impreza,  the cams are non AVCS, these are not the ej20x or ej20y.  

If that's the case should I select another setting like multi-tooth or so or even try V7, any suggestions because I am using the Subaru V1-6 trigger mode?

installed a while now but IIRC they looked similar to the V5/6 setup. Or maybe the US ej205 

thanks, I'll swap them around tomorrow

 

 

[Vaughan]

I would recommend having a crank trigger from the same engine as the cam triggers to ensure you're not trying to use a combination of two different triggers.

[swi]

I thought of that, honestly  but I was thinking since its a link ecu I could have configured the triggers to work

I guess I'll have to get the crank gear for the newer model and try again

[Vaughan]

In general you can with multi tooth and multi tooth missing trigger patterns but subaru v1-6 has a very weird trigger pattern with uneven spacing and repeating patterns, from looking at the trigger pattern for the crank it has 2 teeth close to each other then 1 a bit further away then a big gap then it repeats that pattern. This means that over an engine cycle you have the same pattern four times meaning you can't be sure which of the four possible positions you are in. The cam teeth for subar v1-6 have a group of 3 teeth, a big gap, 1 tooth by itself, big gap, 2 teeth, big gap, 1 tooth, big gap then repeats.

The v7-9cam has 4 evenly spaced teeth, this means that when you combine this and v1-6 you know when you are at top dead centre but you don't know which cylinder is at top dead as there is no distinct thing to tell the ECU which cylinder it is up to.

With generic trigger patterns you have evenly spaced teeth and often a gap. this gap can tell the ecu what angle the crank is at and then it can use a pulse from the cam to tell it which half of the engine cycle it is in and so this kind of pattern can have things moved around and different cam teeth patterns.

From looking at your trigger scope it looks like you have the normal subaru v1-6 crank pattern and have 3 teeth and a gap all evenly spaced on the cam, this could theoretically work as you pick the 3 teeth on the crank which don't have a cam tooth as your sync point but due to the unevenly spaced teeth this would require a custom trigger pattern to be built into the firmware. If you tried to use a multitooth mode it assumes the teeth are evenly spaced and so will think that the engine is speeding up and slowing down massively between each of those crank teeth making it impossible to be precise about the current location

[swi]

ok thanks, greatly appreciated 

I'm using the cam gear on left with crank sprocket on the right, so i'll swap out to the crank sprocket and use both on the left. 

This should cure the problem then, I trust

[swi]

and of course trigger using the JDMv7-10 trigger mode

 

[Vaughan]

should do

[swi]

thanks Vaughan,

makes prefect sense, I was of the assumption the V5/V6 used the same gear but having NOW researched they all use the 7 trigger points on the rear like all GC8s. 6 crank 7 cam.

that's what I couldn't wrap my finger around. Review of the waveforms really cemented it and of course your expertise.

 

thanks a million, you've been fantastic

 

cheers

[Adamw]

Has the sensor wiring been messed with as well?  The waveform is very distorted but it looks like they are wired incorrect polarity (+/- swapped) too.  Post another scope once youve got a matching cam/crank trigger set but Im suspicious there is a wiring problem too. 

[swi]

hi Adam, yes they have been, Vaughan pointed that out in his first post.

thanks for the assist, I'll have it sorted tomorrow

[swi]

I set the triggers to that of the v7-10 jdm and the trigger arming  threshold to the v7 and it fired right up.

 

thanks again guys

 

 

I scoped the new waveform but I somehow lost them or didn't save them in the correct format, so i'll take new ones and upload those later.

[swi]