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hAVE A 87 GN WITH A MAX BOOST OF 7LBS. ANY IDEAS OF THINGS TO CHECK FOR THIS PROBLEM WOULD BE APPRECIATED usa
 

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Check the headers for any major cracks. Check to see if you have a plugged cat. Check the boost seloniod on the passenger valve cover. For a quick test you could pull the vac line off the compressor housing of the turbo. But be cautious because boost can hit 30psi so just step into it slowly to see if if boosts more and do not floor it. One more thing, you do have a proper boost gauge and not the led one, right?
 

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i used to only get 8-9 psi when i first bought the car.turned out the Y was backwards.check the Y and see if it is correct.i think the little "orifice" should be facing towards the turbo
 

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Make sure you are not taking your boost readings from the stock LED gauge in the dash, it's seldom accurate. If you don't have one already, a mechanical boost gauge like a VDO is a must on these cars... powersix
 

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forzfed:
Check the headers for any major cracks. Check to see if you have a plugged cat. Check the boost seloniod on the passenger valve cover. For a quick test you could pull the vac line off the compressor housing of the turbo. But be cautious because boost can hit 30psi so just step into it slowly to see if if boosts more and do not floor it. One more thing, you do have a proper boost gauge and not the led one, right?
I'm having the same problem as Spooly....If removing the vac line from the housing enables you to get more boost, then it's a solenoid problem, huh? Is this solenoid an easy to get part from Napa, or will I be ordering this from freakin' Beijing?
help powersix
 

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I bought a couple from Kirban, I don't know how available they would be if at all at the dealership. I don't think you'd be able to get them at an after parts store.

I know my higher milage car was running low boost when I first bought it. I thought it was the seloniod so I borrowed the one from my other car and sure enough that was it. So that is another thing you could do if you know someone else with a turbo buick, you could borrow theres an see if that is the problem.
 

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A dirty or malfunctioning boost solenoid can also allow overboost as well. Mine seems to be dead, and I was having bad spikes and overboost. I removed the line from the solenoid, and plugged it tight. Then running off the wastegate only, it was perfect. Boost shot up to wherever it was set and stayed there. No spike whatsoever. However, my WG rod is all the way in, and is maxed out at 15 psi at the moment. Also runs it solid through all gears, which can be bad at higher boost, since it doesnt allow the ECM to take some out in high gear to avoid detonation.
 
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