Builds Boost to 5-6 PSI ONLY

AntMan

Member
Joined
Jul 26, 2012
After changing the valve cover gaskets (which were original) on my 87 BGN W/134k my boost only goes up to 5-6 PSI (between 10-20 mph) thereafter the engines sputters and hesitates until speed reaches 45-50 mph then smooths out at light throttle only.

Also the boost gauge jumps to 10-15 psi as the sputtering occurs.

Any ideas?
 
I would double-check and make sure you put the spark plug wires back on in the correct order.
 
run a brand new hose from the turbo's compressor housing straight to the wastegate and see if it still does it.
 
Spark Plug wires are in proper firing order, engine runs smooth, replaced the vacuum hose going directly between Waste-gate and Compressor symptoms seemed a tad bit better but still present.

Had a second thought, problem occurred 15 miles after filing up w/87 octane fuel.......I'm running a 93 Octane Chip could this be an issue maybe the computer is retarding timing or some other operation to prevent knocking?

Note: This is a new car to me and I seem to recall the previous owner told me he used 93 octane.
 
You should put the best octane you can in the car. Were you hard on it with the 87 oct in it?

Is this your first turbo buick?
 
Even with low octane gas you should still have full boost. You'll just blow the engine up, but you should still have full boost.....


I guess it's time to check coolant level, oil level, and pull the plugs and see if one or more looks steam cleaned.
 
Had a second thought, problem occurred 15 miles after filing up w/87 octane fuel.......I'm running a 93 Octane Chip could this be an issue maybe the computer is retarding timing or some other operation to prevent knocking?

Note: This is a new car to me......

This will be an old car to you if you keep doing that. Don't take this as an insult, but rather some advice, but putting 87 octane in and boosting is pretty foolish. I would put that in the same list as driving your car in the rain, parking it at a mall, giving it to your kid as their first car, trusting your stock boost gauge and using your upper door pull straps to close your door :)
 
always willing to listen, it was just my 1st fill up, went cheap (effing gas is expensive these days as we all are aware) lesson learned, but I did not ride her hard. Still tinkering around with the problem at this point I'm convinced it's not any thing serious like catastrophic engine failure (no leaks, no smoke no loss of oil or antifreeze). I'll keep plugging away.
 
If you think 93 octane is expensive this might not be the car for you.. No offense

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Had a second thought, problem occurred 15 miles after filing up w/87 octane fuel.......I'm running a 93 Octane Chip could this be an issue maybe the computer is retarding timing or some other operation to prevent knocking?

Yes, the ECM can pull spark advance and reduce boost. This would be due to knocking (detonation) from the 87 octane fuel. Siphon out as much fuel as you can then fill it up with some 93 octane. See if it helps.

Even at $4.25 a gallon, Sunoco Ultra 93 is the only fuel I put into the tank.

RemoveBeforeFlight
 
Judging by the original post - he pulled the valve covers.
So, it might be a safe bet to assume the Boost modulating valve or associated turbo wastegate boost lines were not reconnected properly.
I'd look there first.

Also states the "boost gauge" (probably means the Boost LED array) "spikes"
A sign usually that there is a vacuum line off - you see a little blip, then it blows out the open end.

Look near the heater control valve on passenger side - where the line to he MAP sensor is connected to the vacuum block hard line..
Or at the heater control valve vacuum connection
Probably a split boot, or lines not properly reconnected - or 25 year old rotten lines, no tie wraps etc
Check em all.
There aren't that many
Replace any that are old.
 
always willing to listen, it was just my 1st fill up, went cheap (effing gas is expensive these days as we all are aware) lesson learned, but I did not ride her hard. Still tinkering around with the problem at this point I'm convinced it's not any thing serious like catastrophic engine failure (no leaks, no smoke no loss of oil or antifreeze). I'll keep plugging away.

LOL - gas is as cheap as it's been in years.
Approaching 3 bucks.
Not what I call the deal of the century - but much better than what it was.
You can't operate these cars on a budget - I mean - a small budget.
 
It's all relative, would you believe in July 2001 gas was .79 cents per gallon in April of 2009 $1.49 per gallon after almost 8 years now gas has exceeded $3 per gallon for almost 3 years running so if a 100% increase in price is cheap then might I suggest it's Normalcy Bias which has you believing gas to be cheap!!!
 
Yes ineed, parts & labor have risen along with everything else as a energy (fuel) component is attached to it's price........
 
It's all relative, would you believe in July 2001 gas was .79 cents per gallon in April of 2009 $1.49 per gallon after almost 8 years now gas has exceeded $3 per gallon for almost 3 years running so if a 100% increase in price is cheap then might I suggest it's Normalcy Bias which has you believing gas to be cheap!!!

LOL @ Normalcy bias.
Yeah - I'm a mindless sheeple gladly taking whatever government or corporate America wants to put in my dog food bowl.

It is what it is.

My solution to it is to simply do better at making and taking other peoples money. Legally.
Cuz it ain't never going to go down.
Unless the entire world economy collapses - again.

Besides - I look at it as recycling.
I pay more for gas, but I also make more money selling my wares to the Oil & Gas industry, who have had some of their best years in a long time.
Sorta a wash.

You know - they say statistics are like prisoners.
They will say anything you want if you torture them long enough.

You conveniently cited April of 2009, smack dab in the worst economic collapse in a century.
The lowest point on the attached chart. Good choice of a data point to try to make an argument.
But if you look at the attached graph, you'll see that was a complete outlier - and an anomaly after the crash in all prices.

The price run began in the late 90's when the rest of the world began to really soak up the capacity.
We had it really good - for a long time. Now that was "normalcy bias".
 

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Yep, totally agree......the game is rigged and designed for us to never get ahead, however, one must find a way (many exist) glad you found yours!
 
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