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Old 03-20-2019, 08:18 PM   #1
diveplane
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tell tale signs

ok guys need some expert help, my trucks started to make a whistling noise
sometimes not all the time and then dies down when i slightly rev the motor
this a injector going bad? or vac leak on tbi gasket? as it sounds like its coming from tbi..

truck seems to be still running ok ..
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Old 03-21-2019, 08:35 AM   #2
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Re: tell tale signs

Try to find a way to recreate the noise, then use a stethoscope to pin point the noise.

For vac leaks, you can spray down the area with carb cleaner and listen for a change in RPM.
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Old 05-03-2019, 05:31 PM   #3
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Re: tell tale signs

probably the TBI gasket. Mine did the same thing.
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Old 05-09-2019, 04:41 PM   #4
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Re: tell tale signs

ok any videos on gasket replacement? never done this before easy job guys ?
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Old 05-10-2019, 06:19 AM   #5
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Re: tell tale signs

Verify that's where the leak is first. If it is, make sure the bolts holding the TB down are torqued to spec. If that doesn't work, it should be just pulling off the TB, pull put the gasket, clean up the surfaces, put it back together. Don't let anything fall down the intake.
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Old 05-10-2019, 09:34 AM   #6
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Re: tell tale signs

Using carb cleaner safe while engine is cold? Makes me nervy
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Old 05-10-2019, 10:18 AM   #7
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Re: tell tale signs

The test for a vacuum leak is to spray carb cleaner around the gasket area while the engine is running to listen for a change in RPM. No issues with ignition, even on a hot engine.
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Old 05-19-2019, 12:38 PM   #8
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Re: tell tale signs

engine rpm increase or die down if carb cleaner hits leak?
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Old 05-20-2019, 07:10 AM   #9
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Re: tell tale signs

increase
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Old 05-24-2019, 11:57 PM   #10
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Re: tell tale signs

got the tbi off wow it is indeed the gasket its toast, crumbled right off like nothing, got nice new one to install, also need to renew the idle air valve connector as that broke right off , plastic was so bad on it.
also renew fuel line o rings.
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Old 06-11-2019, 01:54 PM   #11
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Re: tell tale signs

truck runs like a champ now sounds better as well.. brilliant thx to all who helped us.
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Old 06-11-2019, 02:14 PM   #12
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Re: tell tale signs

Glad to hear you got it working!
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