NismoNationRB25 Posted May 10 Report Share Posted May 10 SO I'm coming from the Nistune platform, not very informed with the link but need the car running to really dive into it and learn it. Car starts and runs with both nistune ecu and Stock ecu. RB25det Neo engine Installed a PNP gtt g4x Ecu *I have a strange issue where car is struggling to crank and turn over the engine* set base timing to 15 degrees BTDC and had no change in the cranking issue. ( I unplugged the coils and the problem went away, I'm assuming its a timing issue but have no idea how to rectify it.) what do i need to start looking at to diag this issue and get the motor started? PC Datalog - 2024-05-9 1;02;06 pm.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 10 Report Share Posted May 10 Your battery voltage drops to about 5.5-6V when it kicks back but it is a bit hard to tell if that is just due to the kick back or is the cause. There are also patches of trigger errors but again these could potentially just be caused by a kick back. What is your existing trigger offset? Are you using an HT lead between the coil and spark plug to check timing? The timing loop will give incorrect timing with many timing lights. Quote Link to comment Share on other sites More sharing options...
NismoNationRB25 Posted May 15 Author Report Share Posted May 15 On 5/10/2024 at 2:30 AM, Adamw said: Your battery voltage drops to about 5.5-6V when it kicks back but it is a bit hard to tell if that is just due to the kick back or is the cause. There are also patches of trigger errors but again these could potentially just be caused by a kick back. What is your existing trigger offset? Are you using an HT lead between the coil and spark plug to check timing? The timing loop will give incorrect timing with many timing lights. Took off CAS and spun by hand to see if spark and injectors were working. All verified working. Changed reference timing to 15. Trigger offset is at 0. Spontaneously have no more kick-back issue, cranks easier but still no start. Trigger errors stopped popping up after the motor was turning over easier. I'm using GM truck coil packs and testing for timing on the spark plug wires not the the timing loop. While cranking the car the timing light doesn't pick-up any signal, but when i use the test ignition function the timing light lights up. I've never had an issue with this setup and this timing light before i changed the ECU. I have read on another post you suggesting opening the spark plug gap to increase voltage, which i will do and update. I figured the base map link provides is close enough to at least rough start this engine. Not really sure what to look for to help get this motor running, Not sure what the signals on the trigger scope is supposed to look like. if anyone has some bullet points or some literature for first starts on this ecu that i need to hit please share them (I've read through the info on the booklet that came with ecu, followed the instructions and checked to make sure everything was wired correctly). Thanks all PC Datalog - 2024-05-14 1;06;27 pm.llgx Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 15 Report Share Posted May 15 The trigger offset would normally be around -90 as per the GTT base map so I would start there. The reference timing setting is what you use to tell the ecu what to lock the timing at while you set the base timing. If your timing light isnt flashing then that is no use to you. Have you confirmed you do actually have a spark when cranking? Are you using an ht lead between the coil and plug? Quote Link to comment Share on other sites More sharing options...
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