Bryan_FC3S

Hi,

I have a JDM s5 turbo.
I noticed yesterday that when I turn the key on, but leave the engine off, I could hear a clicking sound from the engine bay.
After searching around, I found that is the turbo solenoid clicking. The clicking stops if I pull the plug on this solenoid.
is this normal behaviour? My understanding is that this should only actuate under boost?
If I disconnect the boost pressure sensor the clikcing stops. And it also stops if I press the accelorator. All with the engine off.

Video of noise: https://youtube.com/shorts/v_r6VsXnIGM?si=UoMsAc_VbHFiVsZw

Is there an issue here or is this normal behaviour?
thanks

Bryan_FC3S

Update:
I think issue might be due to TPS needing adjustment.
narrow range is measuring 1.2V with engine on and close throttle. Full is measuring 1V.
I think these should be 1V and 0.8V respectively.
I will take the car for a 30 minute drive and measure these again because ive read that this should be done when engine is at operating temp.
​​​​​​
I am thinking it might be related to TPS because thr clicking goes away when I press the throttle 🤔

Bryan_FC3S

Update:
After driving for 30 mins, i checked TPS again.
the narrow range one was like 0.95V so I adjusted screw until it was 1V.
the full range one was still reading high. It was around 1V when throttle closed and 4.7V when open.. I wasn't sure how to adjust this one using the screws.. so I left it alone. I have read that this one just affects OMP so I doubt TPS is the cause of my clicking solenoid

professionalpyroman

The turbo solenoid keeps pulsing while the ignition is in the run position. That clicking means it is opening. The solenoid opens to bleed boost away from the wastegate to pull the turbo up to full boost. When the turbo reaches full boost, the solenoid is closed again so that the wastegate opens and dumps excess exhaust. This is a safety feature to keep your engine from blowing up. If the boost control fails in the ECU, or the solenoid fails, it closes and boost pressure opens up the wastegate at the sprung pressure. This will result in a lower boost pressure to the engine as a precaution.

TLDR, the solenoid clicking is by design and is important to control boost levels. Its fine.

Bryan_FC3S

Thank you for such a detailed response!
glad to hear it is normal when key is in run position. What you are saying makes sense to me.
Now I can move onto the next electrical problem 🙃 (my headlight high beams will sometimes turn themselves off, or stop working entirely while driving. Seems to me like an issue with the switch)