 76 2.0L Decel valve, How do you set this valve |
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| Ron914 |
 Dec 9 2025, 02:36 PM
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Member  Group: Members Posts: 454 Joined: 19-April 22 From: Huntington Beach,Ca Member No.: 26,487 Region Association: Southern California 
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In preparation for my smog test I hope to get this week I need to install the Decel valve as it is original equipment and required . I am trying to understand how the decel valve works and where it should be set .
My understanding (and correct me if I am wrong ) is when the vacuum in the plenum goes high the valve opens and creates a path between the plenum and the air cleaner , this is controlled by the decel valve but at what value . If I lift on the accelerator the vacuum in the plenum goes high thus creating a connection between the plenum and the air intake or cleaner . I would assume you set it high vacuum ( maybe 18-22inHg)I checked the tech notes section for an explanation but could not find what I am looking for . I am actually thinking about screwing in the adjustment screen so that the decel never opens , however it will still appear connected . I doubt they will be checking the actual operation of it .   |
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| emerygt350 |
Dec 9 2025, 02:46 PM
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Advanced Member Group: Members Posts: 3,415 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Mine was set around 23 psi. I think many around here set them to 18 but my engine pulls pretty high vacuum at idle and I don't want that opening up.
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| rjames |
Dec 9 2025, 03:09 PM
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I'm made of metal Group: Members Posts: 4,414 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest
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As emeryGT said, stock setting is ~18 inHg. Keeping it functional may prolong the life of the diaphragm in your MPS.
Detailed info on it can be found here: https://members.rennlist.com/pbanders/DJetParts.htm |
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| Ron914 |
Dec 9 2025, 03:48 PM
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#4
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Member Group: Members Posts: 454 Joined: 19-April 22 From: Huntington Beach,Ca Member No.: 26,487 Region Association: Southern California
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Thanks Robert and Dan ,
When I first got the motor back into the car and running I fought vacuum leaks for a long time and this valve was one of the major offenders . I think I will set somewhere between 18-22 inHg |
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