Cormac Posted March 24, 2022 Report Share Posted March 24, 2022 Hi All. I recently had the Link G4+ set up by my tuner to control boost in my R32 Skyline with RB20DET. Previous to this I was using an external boost controller but wanted the Link ECU to control all this. My tuner set this up with a High/Low boost switch (as I previously had Hi/Lo mode in the boost controller) and that appears to be all wired in correctly as the ECU is detecting the switch being on or off, and I can see two separate Wastegate Duty cycle tables. My problem is this - I have a mechanical boost gauge in the car, and since getting the car back from the tune, the boost level seems to be the same regardless of the boost mode. I even disconnected the wiring harness from the Solenoid and the car didn't feel much different. The car makes about 0.5bar boost up until around 5k RPM when it will climb to almost 1 bar boost. Previously, with the boost controller, it would pull hard up to 1.1 bar at around 4.5k RPM and would maintain this. I'd appreciate if someone can take a look at my map, a log of a short drive and some screenshots from the ECU settings. The first 2 minutes was with the car on low boost mode, then I switched it to High boost for the remainder of the drive, then stopped logging. It might be just I'm not reading the boost gauge properly as I'm trying to drive at the same time - but the car feels somewhat the same in both modes. Thanks! Log of drive is attached here. Had to zip it due to size. R32 Skyline Hi Low boost log.7z Base map attached here. Base Map R32 skyline.pclr Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 24, 2022 Report Share Posted March 24, 2022 The two boost tables are working as they should be. It appears there is just not enough DC down low but it could also be a boost leak or sticky gate. It should really go back to the tuner to diagnose if it doesnt do what you paid for. Quote Link to comment Share on other sites More sharing options...
Cormac Posted March 25, 2022 Author Report Share Posted March 25, 2022 Hi Adam, thanks for the reply. I live quite a distance away from the tuner so wanted to see if it could be something simple that I missed before going back. I don't believe there is a boost leak but I will check for this along with the wastegate. The previous boost controller would constantly overshoot the target and hit the MAP limit, hence why I wanted the Link to control boost, as I thought it would do it better. Is there any chance it could be the solenoid itself which is faulty? Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 25, 2022 Report Share Posted March 25, 2022 5 hours ago, Cormac said: Is there any chance it could be the solenoid itself which is faulty? Chance, but unlikely. Quote Link to comment Share on other sites More sharing options...
Cormac Posted June 27, 2022 Author Report Share Posted June 27, 2022 Hi @Adamw Thanks for your earlier replies. I have just gotten the car back from getting some paintwork done so did not have the chance to troubleshoot this further until now. I plan to go back to the tuner to diagnose if I can't figure this out, but have checked over the basics and feel it could be something small that was missed when my tuner set up the switchable boost. The behaviour of the boost is still the same as seen in the earlier log of my drive - rises to 0.5 bar and holds steady until around 5k RPM, where it will slowly climb to approximately 0.85 bar before redline. Here is what I have ruled out: Waste gate actuator is fine and not sticking. Removed the boost source from the actuator and went for a careful drive. Boost is coming all the way up to 1.2/1.3 bar and would have kept going had I not backed off. This also rules out a boost leak. Connected the wastegate actuator directly to the boost source on the intake manifold, so it is running wastegate pressure. The boost behaviour is identical. Reaches 0.5bar and then climbs a bit as the RPM gets higher. Now I am suspecting the boost control solenoid, but as you suggested, no issues. I gave one wire 12V and when grounding the other wire, it is audibly clicking. Now I suspect the wiring from the Link ECU to the solenoid. Both pins on the wire are around 12V when ignition is on. I assume one wire would pulse to ground when on boost but don't have a way to test this. So I have ruled out - wastegate actuator, the solenoid, a boost leak and the wiring, but still I have the same issue. Is it possible the Wastegate % duty cycle tables in my screenshots above were created, but never "activated". Is there some setting I can check via PC Link? Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 27, 2022 Report Share Posted June 27, 2022 I noticed in your map the tuner has two boost solenoids set up, one on Aux 1 and one on Aux 8. This will likely cause problems. You need to work out which aux your solenoid is connected to and turn off the other one. To work out which one it is connected to you could set each aux to "Test (pwm)" and the solenoid should click if you have the right one. Quote Link to comment Share on other sites More sharing options...
Cormac Posted June 29, 2022 Author Report Share Posted June 29, 2022 @Adamw You were exactly right. Aux 1 was wired to the Solenoid which I confirmed by setting it to Test (PWM). I turned off Aux 8 and now the car is boosting perfect and holding steady at 1 bar. Thank you for the solving this! Quote Link to comment Share on other sites More sharing options...
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