Viggen Overboost

[Fast_Ed]

Been having an issue with the boost on my Viggen surging way into the red... To the point where it hit fuel cutoff.

This is obviously bad news for the engine, turbo, tires, etc...

Testing yesterday also yielded a situation where it have no boost. Then to much boost again.

I went to unplug the boost control solenoid today to eliminate it from the loop, and it fell completely apart!!

Naturally, I have a spare and swapped it in. It now appears to boost normally!

So the question is: will my turbo now suffer a horrific fate due to it's abuse? I think the compressor seized for some time yesterday..... I guess time will tell.

Also, first drivetrain content is turbo related!

[Adam]

Turbo probably won't fail (unless it has). Overboost is more of a danger to your engine rather than the turbo since they fuel system may not be able to supply enough fuel at really high boost levels. The turbo may run the risk of exceeding its rated shaft RPM, but I think the fuel (spark?) cut off would come in before that was even close to a possibility to keep the engine in a non-exploded state.

The no boost situation may have been caused by the waste gate being stuck open? Electronic control should limit it to base boost in case of component failure, but if the boost control solenoid (or rust) was holding the waste gate open, no boost would develop? If only I knew how turbos worked...

[Fast_Ed]

Magic and gasoline goes in.... Horsepower and lag come out. There's some science in there for flavor.

Yeah, on this car, there is no electrical way to order zero boost.

I want to believe the wastegate physically stuck open.. That actuator has a heck of a spring tho. Guess I'll just keep clean oil in it and avoid letting it sit again.

Now to solve the massive oil leak, which will aid the 'keeping good oil in it' part...