Boost Gauge is always under Amer

[Juris]

Please help..for no reason, under or idle cruising, the gauge now is in the amber..and hardly ever in the economy. When the Amber light is lit, the vacuum plummets fro 16 - 18 inches to 10 -8 inches and so does the mileage.

Is this a vacuum problem, carb problem?

I have an '82 Sport Coupe, QJet carb.

 

[b4black]

The amber light is set to come on about 2 psi. The red comes on about 5 psi.

They are both simple pressure switches (combined in one unit). At the correct pressure, they ground a wire completing the circuit for the light bulb.

The boost light switch is near the cruise control unit. It's round, with a hose on top and wiring to the bottom. Try disconnetin the hose, plug it off and see if the vacuum improves. Try disconnecting the electrical connector and grounding each wire with a paper to verify the lights work correctly.

Drive around with the electrical disconnected from the switch and see if it light ups (indicating a short inthe wiring).

 

[Juris]

The amber light is set to come on about 2 psi. The red comes on about 5 psi.

They are both simple pressure switches (combined in one unit). At the correct pressure, they ground a wire completing the circuit for the light bulb.

The boost light switch is near the cruise control unit. It's round, with a hose on top and wiring to the bottom. Try disconnetin the hose, plug it off and see if the vacuum improves. Try disconnecting the electrical connector and grounding each wire with a paper to verify the lights work correctly.

Drive around with the electrical disconnected from the switch and see if it light ups (indicating a short inthe wiring).

 

[Juris]

Thank you so much for your reply...I took the hose off...actually it came off when I touched it...corrosion...then of the hose was corroded. Yes...the vacuum is back where it should be. I'm going to try and clean the orifice by soaking it in white vinegar. That should dissolve the corrosion. I assume that part isn't available for purchase...can you tell me the name?

There are two sensors on the carb one in front and on on the top right hand, can you tell me the function of each?

 

[b4black]

I believe it's just called a boost switch. The same part was used on 84/87 fuel injected Turbo Regal when they had the digital dash option. GM part # 25503871 (You probably have a green switch, replacements are often black.) You came also substitute it with a pair of "Hobbs switches".


The three wire white connector on the carb is for the Throttle Position Sensor (TPS). The other two wire connector (black or blue) is for the mixture control (MC) solenoid.

This is one of the very first computer control engines. I suggest getting a factory shop manual and also getting a scan tool like OTC Monitor. Both shuold be cheap on ebay.

Learn how the computer controls work - don't make the mistake of ripped all the emissions stuff off. Some can be removed, others are worth keeping. Timing and air/fuel ratio is controlled by the computer. And it has a knock sensor on the very back of the block.

 

[b4black]

This will be helpful!

http://www.turbobuick.com/forums/threads/1982-turbo-regal-vacuum-and-wiring.395992/