Kazu

Hi all, just after a little advice.
I've just had a new install of a g4+ in a R34 GTR which has an issue with starting, everything was fine beforehand.
When starting, the engine turns over strongly and fuelling is fine, it just does not start, as if there is no spark. If you then put a booster on the battery it will start and will then also start straight away after its been running.
The battery is new and uprated. I was told this was a common issue with the GTR and link ecu's, that when the battery drops a little, it does not start ??
Im no expert but find this hard to believe and wonder if the ecu has been set up correctly or if there is anything I can do?
Any help will be much appreciated!

This is a REALLY common issue. Every single S15 plugin and 90% of GTR Plugins have this problem.
We get round it in one of 2 ways -
1) use the power from pin 45 to fire a relay which has battery power supplying pins 49/59
2) just use pin 45 to connect to pin 49/59.
Never a problem on OEM ECUs but is on plugins. I have reported this and it is being looked into by Dave@Link in the UK.

The ECU drops out when the starter is engaged.
The only way to fix this properly is to use a Digital Input and set up the Hold Relay Circuit with a diode to stop backfeeding, this will stop the ECU dropping offline and also allow the car to start faster.
Cut the wire to pin 16 and Wire the Relay side of the wire to a spare Ignition output, set the Ignition output to ECU Hold Power.
Cut the wire to pin Pin 45 and connect the relay side of the wire to a Digital Input and ALSO connect this to the Cathode of an IN4007 Diode, The Anode side of the Diode connect to the wire on Pin 49, set the Digital Input to IGN Switch.

Hi Simon/Adam,
I was able to meet Jason (PSI) this past weekend and discussed my issue at an event, and we are thinking the issue could be tied to CAS wiring. Although the car did appear to be "bone stock" from Japan, it's a possibility that the CAS has been changed or wiring modified. I haven't been able to get to the car for the past 2 weeks but I will try this weekend. Power/ground/trig1/trig2 could all be flipped depending on if it's a R32 or R34 CAS. I'm waiting for a picture to be sent so I can see verify which CAS I'm dealing with. 
I'm hoping it will be as simple as re-pinning some wires at the CAS connector. Going to run a continuity test to see where things are wired as well.
speedotech - I'd suggest you verifying this aspect on your setup as well. 
Thanks,
Ed

Hello Everyone,
Hoping to get some help with a 1991 R32 GT-R on a Link G4+ Plugin ECU. I did a search for these issues and tried all the suggestions I found but have not had any luck.
This is a brand new install. The car is a stock 1991 R32 GTR. 
First thing I noticed after installing the ECU was that it disconnects while cranking. Battery was low initially during cranking so I put a charger on it for the remainder of these tests. Even with the charger the ECU would disconnect. We decided to use a power probe to manually apply 12V power to pin 49, bypassing the ECCS relay for now. We did verify 45 had power at key-on. This finally allowed the ECU to stay online while cranking. We also tried dip switches in both positions, R34 and Other. Neither make a difference. The J1 jumper is removed. I reseated the ECU connector a few times, double checking to make sure the sides were not caught on anything or popping up, 10mm bolt is very tight/snug. I don't believe there to be an issue with the ECCS relay system. I've owned the car for the last 2 years and it's never given me a problem, so I'm still a bit confused as to why I need to manually feed it power to stay alive during cranking.
Second issue was now I was not getting any engine speed or spark while cranking. I am using the GTR basemap, I did not go through the Test ECCS Sync procedure. Widest slot was set to 24 per the basemap. I was never able to get spark while cranking so I wasn't able to run through the base timing setup either. I've tried trigger offset values of 0, -82, and -80 without any luck. I am able to use the ignition test function to trigger coil 1 and visually verify spark. While cranking, RPM stays at 0. I setup a new parameters window to watch Trig 1 and Trig 2 Signal, they always stay on 'NO'. I was only able to see this towards the end when we used the power probe to keep the ECU from disconnecting.
TPS calibrated fine. I am using the on-board map sensor.
The only thing I can think of is that the car came with an "Ultra" brand turbo timer. Its never seemed to work and I tried the above tests with the timer on and off. There are no sensors that have been wired in. I also tried unplugging both MAF sensors with no change.
After giving up, I swapped the PCB's and put he stock ECU back in place. The engine fired up on the first crank. 
It was difficult to keep the ECU online while doing these tests so unfortunately I don't have any logs to share. 
Any suggestions would be greatly appreciated.
Thanks,
 Ed