I lost the bottom end of my 87 GN back in October. Got everything rebuilt and ended up losing the main bearing(long story) But also when I got it back it was no longer sticking at 15 pounds boost. Secound rebuild(runs great now)and still overboost. The actuator is fine I'm pretty sure, but I don't know about the solenoid. Can someone help me out by telling me what I'd be looking at and looking for??? (New GN owner) I'm going to end up taking it to Lou's Automotive in Lake Forest, CA ,but I wanted a little head start on what could be wrong.
Thanks,
Mark
Check the vacuum lines at the turbo/wastegate/solenoid. If they are leaking, then you will get overboost. If they aren't, then unplug the hose from the solenoid, and plug the hose. This should stop the overboost if the solenoid is gone and leaking. Good Luck.
Brian
Thanks Brian. I plugged up the hose and now it runs perfect. So what's the point of having a solenoid then anyway? Just Curious.
The solenoid is supposed to bleed off a little boost, from the wastegate, thereby increasing your boost. It is supposed to do this a little, and also open and close, controlled by the computer. I'm not sure, but I believe the computer can control just how much it bleeds off. I think the computer slams it shut when you get knock, limiting the boost but again, I'm not sure. However, if it is bad, it will just bleed it off all the time, giving you really really high boost. That's bad. I've seen alot of people with it eliminated. If you do keep it disconnected from the wastegate, you still have to keep it plugged in electrically, or you will get the SES light. I'm sure someone else out there can explain it better/knows better.
Brian