When boost control solenoids go bad...

[turbojimmy]

....what do they usually do?

I can't control the boost on my GN. I thought maybe it was the WG rod, so I wound it out so that it's out about as far as it will go and still hold the WG shut. Went out and the boost is still through the roof. Thank god for the knock gauge 'cause suddenly I have no dash lights (I'm losing ground with this thing quickly). Couldn't see the boost gauge. As soon as the knock gauge blinked I got off it.

If I unhook the WG and plug the line, I get 12-15 PSI. So what's the likely cause? Solenoid? How do you check 'em? How can I test the control circuit?

Jim

 

[Russ Merritt]

Hook everything back up, (wastegate hoses) and un plug the wires from the boost solenoid valve. If the boost is still high it's leaking somewhere, lines or the valve. Find out which. Good luck!

 

[turbojimmy]

Sounds simple enough - I'll try it.

The dash lights were a pinched wire in my A-pillar gauge pod. My punishment for fixing my FP gauge over the weekend, I suppose. All better now.

Jim

 

[turbojimmy]

Well it turns out I had the wrong "y" in the plumbing. I hooked everything back up with the right "y" and unplugged the solenoid. Boost builds slowly and peaks at 15-17 PSI if I stay in it long enough. Just like with the line plugged.

I haven't tried plugging the solenoid in yet, but I think the wrong "y" was venting boost too fast. The port leading to the solenoid was pretty big - big enough that the right hose was too big for the port on the solenoid.

Thanks,
Jim