CStone Posted March 25, 2023 Report Share Posted March 25, 2023 Hi, I'm having some trouble with the ecu hold power function I wired it as per the help file and it actually worked at first but then the ecu was staying on after key off. in PCLink it was showing ignition active so i checked the voltage and 1.5v was still getting back through the reverse side of the diode after key off. i swapped in another 1n4007 diode and same result. does it need to see 0v there to actually work? is there any way i can change the threshold in PCLink? are my new diodes all faulty? any help would be appreciated Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 25, 2023 Report Share Posted March 25, 2023 That would sound more like a back feed from an aux output. Unplug anything you have connected to aux outputs to see if it then powers down. Quote Link to comment Share on other sites More sharing options...
CStone Posted March 27, 2023 Author Report Share Posted March 27, 2023 well thats interesting cause it started happening after i wired ign 8 to the ac clutch relay. i dont quite understand how it can back feed to a different circuit but il try disconnecting it and see what happens. thanks alot Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 27, 2023 Report Share Posted March 27, 2023 Ign and injector drives cant backfeed, only the auxes 1-8. Quote Link to comment Share on other sites More sharing options...
CStone Posted April 2, 2023 Author Report Share Posted April 2, 2023 ok i unplugged all the aux 1 through 8 and no change.. hmm Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 2, 2023 Report Share Posted April 2, 2023 Are you wired as per hold power method 1 or method 2? Where are you seeing the "1.5V"? Where my red dot is or blue dot or both? Quote Link to comment Share on other sites More sharing options...
CStone Posted April 4, 2023 Author Report Share Posted April 4, 2023 yes thats how i have it wired and ive got 1.5v at the red dot Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 4, 2023 Report Share Posted April 4, 2023 Perhaps the pull-up resistor on the DI is enabled? Quote Link to comment Share on other sites More sharing options...
craig903 Posted April 4, 2023 Report Share Posted April 4, 2023 If you have wired a fuse in between the ignition switch and the ecu ignition digital input as per the drawing, Pull the fuse out and test either side of the fuse carrier. If you have the voltage on ecu side you know its back feeding or the pull up is enabled in software. Quote Link to comment Share on other sites More sharing options...
CStone Posted April 11, 2023 Author Report Share Posted April 11, 2023 the pull up resistor on DI is disabled. I pulled the fuse and the voltage disappears at the ecu side and it powers down as per normal. i still have 0.6v at the ign. switch side. I tried connecting a light bulb from the red dot to ground and that helped to bleed off the excess voltage after key off so the ecu hold power was working but then the iscv wouldnt reset for some reason. i was wondering if it messed up the circuit since the iscv, ign coils etc. are all powered off that same ignition circuit but i dont know whats going on yet. i will keep prodding around and see what else i can come up with Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 11, 2023 Report Share Posted April 11, 2023 When the DI pull-up is disabled there is no path from the DI pin back to 12V internally. The DI's have a weak pull-down permanently connected so with the pull-up off the "voltage" isn't coming from the DI. Can you draw a schematic of how the idle valve etc is connected. Quote Link to comment Share on other sites More sharing options...
CStone Posted May 6, 2023 Author Report Share Posted May 6, 2023 sorry its been a while but I still haven't fixed this. the last thing i tried was removing the diode from the equation and im still getting 1.5 at ignition signal after key off so it must be coming from the car wiring somewhere and not feeding back through the diode. I'll attach some of the schematics from the cars manual if it helps Quote Link to comment Share on other sites More sharing options...
CStone Posted May 13, 2023 Author Report Share Posted May 13, 2023 well i solved it. turns out the guy who made the loom had all the engine sensors, actuators etc. powered off ignition IG2 including the ISCV once I changed that so its all powered off the main relay it started working. ideally i would have only the iscv powered off the main relay but ah well, it works Quote Link to comment Share on other sites More sharing options...
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