I've been chasing this issue on my R32 GTST for about 1 year now, and wanted to call in the help of the professionals! This is my first time making a post on a forum, so forgive me for lack of information; etc. If more information is needed, please let me know and I'll supply!
Background information
Purchased a R32 GTST from Japan in 2020. Had it shipped over here to Orlando, FL and immediately fell in love. The car is Grade 4/5 and I knew I wanted to keep it forever. I'm very meticulous on the car and it's treated very great. The car is 100% Stock. The only thing that makes the car aftermarket is the head unit.
in 2021, I noticed an issue starting the car. In order to start the car, I'd have to turn on the ignition and wait for the "Exhaust Temp Light" to turn on. If I didn't wait for this light to turn on, the car would crank and crank but never start. Once the Exhaust Temp Light turns on, I would hear the fuel pump and that would be my key to start the car. If the exhaust temp light flashed twice, the fuel pump kicked on and off twice to the tune of the exhaust temp light flash.
I then wired the fuel pump direct to the battery with a relay in between thinking the old fuel pump wiring could be the issue. This made no difference. The fuel pump would be on, but the car still would not start until the exhaust temp light turned on. Keep in mind also, the car would sometimes start in limp code with the exhaust light flashing "Code 55 (No Error). If it started in limp mode, it would take a few key cycles of starting the car off and on to clear the limp mode.
So then I went to the ECU. I checked direct power and ground (Pins 58 & 10) and I can confirm power and ground.
However, I noticed on pins 45 (Ignition Switch), 49 (Control Unit Power Supply) and 59 (Control Unit Power Supply) the voltage is all over the place. I did find a blown 10A Engine Control Fuse under the steering wheel, but I replaced it with no change. Another thing I did was run a temporary ground to Pin 16 (ECCS Relay) and noticed no change.
I also cleaned the ground on the battery terminal, frame rail (right below battery terminal) and the two M6 bolt grounds next to the coolant temp sensor.
Notes
-Exhaust Temp Sensor has been disconnected from under the passenger seat
-When the car is warm I can start up with no issues usually.
Video of the issue is also on google drive, link below.
https://drive.google.com/drive/folders/ ... sp=sharing
Pics of my Skyline
