Deceleration Valve
10-07-04, 06:33 PM
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Deceleration Valve
I've heard there is meant to be a deceleration valve somewhere, hwoever my car is EFI, so I'm wondering if it does have one of these, and where I might be able to find it? =)
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10-08-04, 12:29 AM
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i have one on the carb...the guy i just bought it from said that it was the reason it had the small backfire...but i'm not too sure. so i guess i wanna know this answer too.
10-08-04, 02:22 AM
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I think
teh Decelleration Valve is at the top of the Intake manifold i believe.
its purpose is to cut fuel to the 2nd rotor when slowing down.
this reduces backfire and i think also increases the rev drop when you lift off the throttle
with it removed on my car i find that the motor reduces RPMS slower whrn i lift off the throttle than it did before.
I am not sure why thisis a good thing, i think its just to simplify the vacuum system
its purpose is to cut fuel to the 2nd rotor when slowing down.
this reduces backfire and i think also increases the rev drop when you lift off the throttle
with it removed on my car i find that the motor reduces RPMS slower whrn i lift off the throttle than it did before.
I am not sure why thisis a good thing, i think its just to simplify the vacuum system
10-08-04, 09:05 AM
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The decelleration dashpot on the Nikki carburetor is located on the top, right side of the carburetor when viewing it from the primary barrel side. Is consists of a piston plunger, a diaphragm, and oil, and works against a tongue on the linkage the same way a shock absorber does.
It's presence is solely to slow what would otherwise be an abrupt closing of the throttle shaft.
At high RPM, the engine is creating a vacuum that is great enough to suck fuel out of the idle circuit if the flow of incoming air is suddenly cut off. This will often cause a backfire.
Backfiring is not usually hazardous to the engine, but can destroy the inside of expensive catylitic converters in no time.
Since EFI is only fed fuel through injectors and does not always give the engine access to fuel based upon manifold vacuum, I doubt there needs to be a deceleration dashpot.
I am not certain, though.
It's presence is solely to slow what would otherwise be an abrupt closing of the throttle shaft.
At high RPM, the engine is creating a vacuum that is great enough to suck fuel out of the idle circuit if the flow of incoming air is suddenly cut off. This will often cause a backfire.
Backfiring is not usually hazardous to the engine, but can destroy the inside of expensive catylitic converters in no time.
Since EFI is only fed fuel through injectors and does not always give the engine access to fuel based upon manifold vacuum, I doubt there needs to be a deceleration dashpot.
I am not certain, though.
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