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Some strange things with Link ECU

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Hi to everyone. Have some 2 strange things with Link ECU. First is about boost overshoot. Usually after stage 1 (90% duty to wastegate solenoid) I have 30 duty at stage 2. that time was almost 82% on stage 2, while my map with boost target has all the cells to 180 kpa, and 30 to 40% duty cycle. Log from 5 min 30 sec. second issue with mixture. Once, suddenly after engine was started my AFR was around 11. I tried to accel couple of times. even drive my car with couple minutes. Only restart the engine help to get back my AFR to stoich. (log from 6 min) Please find attached files below.

Attached Files

So no-one nows what could it be?

First, you should upgrade your firmware. There has been a change in closed loop boost control especially with overboosting.

With that said though, I think your main issue is in your boost control tuning. I don't think you've spent much time tuning your wastegate duty cycle table and your PID values are therefore not accurate enough to get good control.

Tune it properly in open loop first and then move on to get your PIDs right. You may also change your Stage ON settings at that point.

In your second logfile your battery voltage is around 9.5V instead of the 13.85V it has been. So that indicates your alternator wasn't working and your injector dead time table may not be accurate.

After have a quick look at your logs, I agree with Andy, It looks to me like you need to put more time into tuning the open loop side of your boost control setup before enabling closed loop. In particular, the section you go full throttle, have a look at your boost control PID values, your Integral gain winds up to 15% and stays there, trying to bring your boost down.

To be honest, the open loop boost control in the G4+ is..... dicey. Its possible to get picture perfect results on the dyno, but once the car is back out on the road things generally start going wrong.

Have a watch of this: https://www.hpacademy.com/previous-webinars/045-setup-and-tune-open-loop-boost-control-link-g4-vipec/

Some good info on there :-).

Thanks guys a lot. Didn't know my alternator could behave like that. Will spend more time with boost control

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