Noob overboost problem

[Ricekiller]

Hey guys I'm a newbie here, my 87 gn has an overboost problem and is throwing a code (31 I believe it was). Someone told me my wastegate may be sticking, how could I check this and tell for sure if thats the problem. Any help would be aprreciated, thanks...RK

 

[Buicksx3]

I don't have my "cheat sheet" list of trouble codes handy right at the moment, but I'm pretty sure Code 31 is for a wastegate solenoid (that's the item attached to the PS valve cover with the little wire harness attached to it) not operating. There's a 10A fuse in the upper right-hand corner of the fusebox marked "ECM SOL"; check that first to see if its blown. If the solenoid isn't operating it can't bleed off boost, which will create the overboost condition you're experiencing.

Morgan
'87 GN with chrome bumpers and, um, "a few" go faster parts under the hood

 

[onebadv6]

through down some of that hard earned dough and get you a nice boost controller or a adj. waste gate

but do check to make sure the solenoid did not come unpluged and check the vac/boost lines for damage

have you added a bigger turbo?
you may be out running the solenoid it cant relive the boost fast enough

 

[scottyb]

If the solenoid is closed, the car will not overboost, assuming the rest of the WG plumbing is correct. It will max at the WG spring pressure which is ~10 lbs on the stock WG actuator.

If the solenoid is stuck open, then you could have a problem. It will bleed off too much and the WG actuator won't get the required 10lbs of pressure to open the WG.

First, do you have an aftermarket boost gauge? The stocker is crap.

I don't know the fail safe on the solenoid. I'd expect it to be closed, but I wouldn't gamble my engine on it. Until you get the code fixed AND get a gauge, I'd suggest that you run a single vac line straight from the boost nipple to the WG actuator.