05-17-2013, 01:26 PM #1
- Join Date
- Feb 2008
Testing the Wastegate solenoid, Weber MSX 150
Working on a MSX150 today. Problem with lack of RPM (low boost).
Checked everything over and all checked good. Removed wastegate solenoid and tested it using a 12V battery and by blowing through the ports while energising the solenoid, tested perfect. Or so we thought.
So on the water testing. I was getting a max RPM of 6800-7000. This ski is fitted with the Desperado Stage 2 so should be maxing out at approx 7700-7800
I also had my bost gauge connected and it was showing a max boost of approx 11.5-12psi
While on the water we removed the pipe from the solenoid to the wastegate actuator. And sure enough on flooring the throttle the ski boosted to max and activated the "overboost alarm".
Wastegate solenoid problem.
Retest the solenoid again only this time I tested using a compressed air through a regulator, pressure applied to the port on the solenoid that is connected to the side of the turbo housing.
While increasing the air pressure to the solenoid, I also pulsed the valve open and closed using a 12v battery, I could hear it clicking open and closed up to approx 11-12 psi and then it stopped clicking and the port no longer switched. The pressure applied by the regulator was high enough overcome the power of the solenoid.
I had a couple of spare solenoids and test them in the same way using compressed air. These solenoids continued to open ad closed up to 35psi, and then stopped clicking.
So problem only raised its head when the boost reached 11-12 psi, this pressure was enough to hold the valve open (weak solenoid valve), thus applying pressure to the actuator keeping the wastegate open.
So if you think you solenoid is OK, testing it as above will wil confirm for sure.
Simply applying 12v to open and close it does not mean it is working correctly.
Hope this helps someone in the future.
Last edited by K447; 05-17-2013 at 10:08 PM. Reason: Added Weber to title
05-17-2013, 02:59 PM #2
Nice research! That is very useful information. I've always wondered how these solenoids "fail".
Which type of solenoid do you have that failed? Is it the original, older style that mounted to the side of the turbo... or the newer upgraded style with the bracket off the valve cover?
I have a situation on one with the older style solenoid. The dealer diagnosed it as bad... which I'm betting was based on trouble codes in the ECU... which I can't read. I bench tested it with just a battery like you mentioned and it clicked and changed ports as expected. I put it on the ski and took it for a spin and first try at goosing the throttle I get overboost, check engine indicator, blinking red light, and RPMs limited to 4900 . So we ordered a new solenoid upgrade kit from Randy and I'll be putting it on and testing it out later today.
Thanks for sharing!
05-17-2013, 04:05 PM #3
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