 de-acceleration valve, 914 2.0L |
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| hookrah |
 Jul 27 2011, 03:01 PM
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#1
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Newbie  Group: Members Posts: 2 Joined: 2-August 10 From: Wa. Member No.: 12,005 Region Association: None  |
Does the 73 2.0 L need the de-accelerator valve to operate correctly? What problems, if any, may occur without it?
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| Rand |
Jul 27 2011, 03:18 PM
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#2
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Cross Member Group: Members Posts: 7,409 Joined: 8-February 05 From: OR Member No.: 3,573 Region Association: None |
No. It allows extra air into the intake on deceleration as an emissions control function. The 70-71 cars didn't even have one.
I've never ran with one and never had any problems, or noticeable differences in running. It eliminates one more thing that can go wrong. Some may argue that it is easier on the MPS diaphragm with one. |
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| type47 |
Jul 27 2011, 08:12 PM
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#3
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
QUOTE(Rand @ Jul 27 2011, 01:18 PM)  Some may argue that it is easier on the MPS diaphragm with one. I heard/read that too. Interesting that an L-jet also has a decel (and no diaphragm). |
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| SirAndy |
Jul 27 2011, 08:54 PM
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#4
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Resident German Group: Admin Posts: 41,638 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
QUOTE(hookrah @ Jul 27 2011, 02:01 PM) Does the 73 2.0 L need the de-accelerator valve to operate correctly? No. I ran my 1.7L D-Jet without for years with no apparent ill effects. It does change the throttle response, the engine decelerates faster. RPMs drop quicker and there's less "coasting". That was in fact why i removed it as i wanted a more direct throttle response when letting off the gas. (IMG:style_emoticons/default/driving.gif) |
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| jcd914 |
Jul 27 2011, 08:58 PM
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#5
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
QUOTE(type47 @ Jul 27 2011, 07:12 PM) QUOTE(Rand @ Jul 27 2011, 01:18 PM) Some may argue that it is easier on the MPS diaphragm with one. I heard/read that too. Interesting that an L-jet also has a decel (and no diaphragm). That is because they put it on as an emissions device on both the 2.0 and 1.8. It is quite common device on many car, alot of cars. On deceleration the high engine vacuum causes a very rich fuel mixture. The decel valve opens when the vacuum gets real high (closed throttle while decelerating) helping to reduce the mixture and emissions. That it may help the life span of the MPS is just a fringe benefit. As Andy points out the lack of engine braking effect is noticeable and was always my biggest irritation with it. Jim |
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| 76-914 |
Jul 27 2011, 09:50 PM
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#6
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,502 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California 
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I pulled mine because it was leaking. No performance change however a small amount of a muted popping is noticeable when decelerating a cold engine. After 2-3 miles it goes away.
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