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Possible Vacuum Lines Missing???

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Old 10-17-2017, 07:41 PM
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Possible Vacuum Lines Missing???
My 89 RS 305 TBI Has a Random Hissing Sound When the Car is Running Pop the Hood and U Hear it Hissing Cant Tell Where its Coming from but as the Car Warms Up and Drives It Goes Away After its Running you still Hear it Just not as Much when the Car is Warm and Idle Drops to about 900Rpm (Normal) But can Anyone give me Info Where to Start Looking And what to Becareful Of Thanks
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Old 10-18-2017, 08:17 AM
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Re: Possible Vacuum Lines Missing???
aRE yOU rUNNING aN oPEN eLEMENT aIR-cLEANER iF sO tHE hISSING iS fROM tHE iac

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Old 10-18-2017, 08:38 AM
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Re: Possible Vacuum Lines Missing???
Actually no...i dont have a air cleaner ha ha took me by surprise
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Old 10-18-2017, 08:55 AM
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Car: 82 TA 87 IZ L98 88 IZ LB9 88 IZ L98
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Re: Possible Vacuum Lines Missing???
Iac passage and cold higher iac position.
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Old 10-18-2017, 08:58 AM
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Re: Possible Vacuum Lines Missing???
Originally Posted by Twin_Turbo
Iac passage and cold higher iac position.
Sorry but what does IAC Mean ?
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Old 10-18-2017, 09:07 AM
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Transmission: T5, 700R4, T5, 700R4
Axle/Gears: 3.08, 3.27, 3.45, 3.27
Re: Possible Vacuum Lines Missing???
Idle air control
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Old 10-18-2017, 09:16 AM
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Re: Possible Vacuum Lines Missing???
Originally Posted by Twin_Turbo
Idle air control
Thanks i will be sure to check that do u know where it is Located?
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Old 10-18-2017, 12:11 PM
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Re: Possible Vacuum Lines Missing???
Round thing protruding from the right hand side of the TBI unit. Has a square 4-wire connector on it. Note that the hissing is normal, with the stock air cleaner it can't be heard.

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Old 10-18-2017, 12:22 PM
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Re: Possible Vacuum Lines Missing???
Originally Posted by RBob
aRE yOU rUNNING aN oPEN eLEMENT aIR-cLEANER iF sO tHE hISSING iS fROM tHE iac

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Old 10-21-2017, 07:25 PM
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Re: Possible Vacuum Lines Missing???
I have the same hissing sound with my tbi since I've had an open element air cleaner. Sounds a little alarming, but it's ok, and it runs very well.
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