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G4 GTS - Ignition #3 not firing / injectors live with ignition off


Phlex32

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RB25DET in an R32 using RB20DET loom and wasted spark mitsi coils. wasted spark previously tested on an earlier engine.  Trying to get the car running to take it for a tune 

Ignition #1 and #2 work in test mode. Car starts and runs on 4 cylinders 

I have tested coil hooked to #3 using the trigger from a different channel and confirmed it fires, Updated firmware, swapped spark plugs around - no joy

ECU purchased second hand with the engine. Engine previously had stock coils but I do not have these. Have switched setting in pclink to "Wasted Spark" although I get the same test effects when set to "Direct Spark" however it doesn't start set to direct spark 

Also with ignition off spinning the CAS fires the injectors - unsure if that's related

Is there a setting somewhere that I need to change to activate the other cylinders or is there an issue with the ECU?

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Just an update to the above. Have now checked continuity from ecu to ignitor plug and from other side of ignitor to coils and all is well there.   Have also tried a different ignitor and exactly the same issue 

 

surely theres a setting that’s not right on the ecu 

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Upload your map, also how have you wired the coil pairs

 

 1&6, 2&5, 3&4?

 

As for the injectors firing with key off, make sure any ground sinked injector/aux outputs are only powered with the key in the ON position or you will have back feeding

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Thanks Leiden, I’ll try and upload the map tonight to see if anyone can make sense of a missing or incorrect setting. It’s not tuned for my engine yet I’m just trying to get it to idle so it can be trailered to a tuner 

Coils are wired as you suggested and it’s 3/4 that isn’t firing. That particular setup worked on my old engine/stock ECU and uses an r32 ignitor 

when you say only powered with key on is this a setting in the link or do you mean physically?  The wiring is standard RB20DET with injector plugs changed, TPS wiring changed and extended and VCT wire added.  No unused plugs have been removed at this stage to keep things simple 

 

 

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Right we made some good progress last night. My friend came round and was able to find the settings for the ignition channels, number 4 was the only one unlocked and was set to on which was somehow not letting number 3 work. Disabling has fixed the issue and all the plugs are now firing and it’s running on 6 

it seems when the battery is first put on but the key is off there is no power to the link. After the key has been cycled on and off there is 9 volts left at the ECU and it stays connected to pclink. Taking the battery back off and on again doesn’t allow it to connect to pclink until the key has been cycled.  Anybody got any ideas before I start ripping the look apart? 

 

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You will have a back feed to the ECU via one of the Aux outputs.

This is where a device has a hot feed that is not switched off with the key such as a boost control solenoid or a fuel pump relay as likely examples. 

Head to the pc link help file 

Navigation:  G4+ ECU Tuning Functions > Auxiliary Outputs >

Wiring Auxiliary Outputs

 

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  • 2 weeks later...

Just wanted to give a bit of an update for anyone who has the same issue. After many unpluggings and lots of head scratching I remembered we took a 12V feed off the injectors for the VCT solenoid as I had been recommended by somebody who does this a lot more than I do and unplugging VCT seems to have fixed the voltage backfeed and the injectors are no longer live.

Would this potentially be a sign of a bad VCT solenoid or was the injector power not the right place to tap this in?

The previous owner of this engine did not have VCT wired up 

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The injectors have a hot feed so it is not switch with the Key. But this is not an issue on the plugin as the injector drives will not allow a back feed. However an Aux drive will. 

The Coil power supply will be switched so this could be used. 

 

 

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