1997 Volvo 855 GLT Turbo Control Solenoid Teardown

[jreed]

Just a short post to report on a fun project to replace my old TCS with a newer one and take another old one apart (from another junked car) to see how it works. I recently found a relatively new TCS (also called a Boost Control Solenoid) on a junked '96 turbo wagon. I replaced my old original TCS (which was date stamped from 1996) and I was pleasantly surprised how much faster the boost builds, and the peak boost under full throttle. With the old one it used to take a few seconds (2-5s) to build up to full boost, and the peak boost was in the 3-4 psi range. With the newer valve installed, the peak boost is 4-6psi and the engines reaches peak pressure in about 1s under full throttle. It's a noticeable increase in the speed of acceleration.
Cutting open the old valve:

Opening up the clamp on the old TCS

Cutting TCS clamp ring 1.jpg (171.6 KiB) Viewed 448 times

Opened up for inspection

TCS interior 1.jpg (181.55 KiB) Viewed 448 times

The piston with sealing surface

TCS interior solenoid 1.jpg (148.19 KiB) Viewed 448 times

The sealing surface on the outer case

TCS interior seal 1.jpg (199.54 KiB) Viewed 448 times

The piston interior and the spring

TCS Spring 1.jpg (173.79 KiB) Viewed 448 times

I applied 12V to the solenoid to see how it actuated. The current draw at 12V was about 0.5A, in line with the 24 Ohms stamped on the side of the newer TCS. I made a very short video clip of the solenoid pulling the piston inside when voltage is applied:



Newer TCS from a junked car:

The newer (date code 4/2007) TCS from junked car

Newer 2007 TCS 1.jpg (198.01 KiB) Viewed 448 times

Installed:

New TCS installed (Yellow on top, then red, then blue)

TCS installed with Yellow Blue Red 1.jpg (176.11 KiB) Viewed 448 times

Quick project that made a nice improvement in the car's response. Well worth it!