TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

whistlin` tbi

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Old 10-17-2005, 09:55 PM
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Car: 1988 camaro "SS"/ 1991 305/T5
Engine: 383 LT1 in progress/LT1TBI 355 soon
Transmission: Probuilt 700R4 3600 stall/ T5
Axle/Gears: Moser axles, 3.42 Eaton Posi
whistlin` tbi

hey guys a quick one for ya.since i `ve owned my car i have had a bit of a miss in it(2 years) now i have tried many routes on what could be causing this problem.(tps connector,iac,bla bla bla)but recently i have noticed a whistling sound coming from my throttle body.i have heard it only once before but it was very brief but now if i BARELY push on the throttle i hear this high pitch whistling. i`ve checked all of my vacuum lines and gaskets that would be associated with vacuum and nothing.the loudest place to hear it is from the passenger side.does any body think that it could be my throttle shaft bushings by the tps?while driving the only time there is much of a problem is when i barely hold the throttle the car surges and when i let off while coasting the idle jumps up and down as well.any thoughts?
Old 10-18-2005, 02:31 PM
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Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
It could be a small vacuum leak. Trace all vacuum lines as well as the base of the TBI unit.
Old 10-18-2005, 04:01 PM
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Car: 1988 camaro "SS"/ 1991 305/T5
Engine: 383 LT1 in progress/LT1TBI 355 soon
Transmission: Probuilt 700R4 3600 stall/ T5
Axle/Gears: Moser axles, 3.42 Eaton Posi
did that.i`ve checked everywhere that i could think of.
Old 10-18-2005, 06:18 PM
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Car: 91 V8 Firebird
Engine: LO3 305 TBI V8
Transmission: 700r4
Just a suggestion, But I've heard whistling noises can be produced by a small exhaust leak where the exhaust manifold or header meets the head. I can't remember exactly how to test for this, maybe spraying soapy water around the exhaust manifold gasket area (on a cold engine) and watching for bubbles. Maybe someone else knows a better test.
Old 10-18-2005, 07:36 PM
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Car: 1999 Yamaha Banshee
Engine: 379cc twin cyl 2-stroke stroker
Transmission: 6 spd manual
Axle/Gears: 14/41 tooth
You should know if it was an exhaust leak. I'd go over all your vacuum lines one more time. If you think that bushing is leaking, then spray some carb cleaner or starting fluid in the area (on it) and see if the RPMs raise slightly...

How does the car run?
Old 10-18-2005, 10:14 PM
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Car: 1981 Buick Century Wagon
Engine: 87 GN engine
Transmission: 2004R
Axle/Gears: 3.73
I've had cars and trucks come into my shop with a high pich whistle, when I couldn't trace the lines or other obviose things, I found the intake gasket bad. I personally had this happen to my bbc chevy in my el camino.
Old 10-19-2005, 03:57 PM
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Car: 71
Engine: 406
Transmission: Auto
Axle/Gears: 3.42 8.5" 10b
Aren't there some vacuum lines that go to the heater box for controls, etc.? Perhaps the Other end of the vacuum line is off, but still on at the TB.

Also, take a look at your PCV valve.

Other suggestions:
AIR pump connections, AIR pump exhaust check valves ( the things the AIR lines hook to on the exhaust manifolds)

Will it do it in the driveway? How bout if you brake torque it a little. .....If so, block the wheels and have someone else operate the car while you're under the hood.
Old 10-19-2005, 05:27 PM
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Car: 1988 camaro "SS"/ 1991 305/T5
Engine: 383 LT1 in progress/LT1TBI 355 soon
Transmission: Probuilt 700R4 3600 stall/ T5
Axle/Gears: Moser axles, 3.42 Eaton Posi
all my air stuff is gone.yeah it does make the sound sitting still.i have checked all the bolts lines and gaskets.i know i have a small intake leak because alittle oil leaks from the gasket on the front of the block.at this point and time i am still not sure whether that could be the cause of the sound.i`ll post some pics of it when i get my camera back.
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