Forum » General Tuning Discussion » R33 GTR Link g4+ goes offline when cranking HELP!

R33 GTR Link g4+ goes offline when cranking HELP!

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hey guys, i'm having an issue with this R33 GTR with a link g4+. i have tuned a previous r33 with the same setup and same ECU so i uploaded the tune from that car to this one to get a decent baseline for first start-up. the car has a brand new rebuilt engine everything was going really smooth except for trying to start it. We have installed r34 gtr tomei poncams with a R34 GTR CAS and we have re-wired the cas pigtail properly to accept the new CAS. my issue im having now is as soon as i try starting the car the ECU goes OFFLINE! and for that reason im not getting any spark. if I turn the cas by hand with the key to ON position i get spark, i also get spark when i run a spark test through the link.

what could possibly cause this??

The ecu going offline indicates it is losing power. First check the main connector is fully seated - We have seen nissan ecu's where the center bolt has been tightened but the connector is bent out at the ends and not fully home.

The ECCS relay is controlled by standalone hardware on the bottom (adapter) board of the ECU so it is not related to ECU settings etc. It is most likely a wiring or connection problem in the car. I will give you a bit of info to help diagnose:

The ECU first receives a +12V "ignition switch" signal into pin 45. This should measure battery voltage whenever key is on and during cranking.

Whenever Pin 45 is live, the ECU sends a ground signal out of pin 16 - this goes to the ECCS relay coil to engage the relay.

When the ECCS relay is engaged that connects battery voltage to pins 49 or 59 (or both) and will power up the ECU.