dashpot 87 4runner automatic needed?
01-29-2014, 08:22 AM
#1
dashpot 87 4runner automatic needed?
Hi
1987 4runner, 22RE, automatic, DLX
doing a engine switch and mechanic says I'm missing dashpot(?) a nutted, bolt thru a small plunger assembly which attaches on the throttle body linkage. I think some say this regulates deceleration during manual shifting gears (SR5 usually) I have automatic DLX model. Do I need to replace this?
think it fell out or maybe was never there. thanks , letted
1987 4runner, 22RE, automatic, DLX
doing a engine switch and mechanic says I'm missing dashpot(?) a nutted, bolt thru a small plunger assembly which attaches on the throttle body linkage. I think some say this regulates deceleration during manual shifting gears (SR5 usually) I have automatic DLX model. Do I need to replace this?
think it fell out or maybe was never there. thanks , letted
01-29-2014, 09:27 AM
#3
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Mine has one (but it's a 3VZE Automatic Pickup '94).
Just so you know, the purpose of a dashpot is to protect the exhaust system and reduce emissions. Particularly when cold, fuel clings momentarily to the intake manifold, before turning into vapor and entering the cylinders. At steady state this makes no difference; cold fuel is depositing and evaporating at the same rate. But if you jump off the throttle, the air flow suddenly drops to almost nothing, but the fuel is still evaporating inside the manifold. This suddenly enrichens the mixture, which will not ignite in the cylinder, but may ignite inside the hot exhaust system. Producing an exhaust back-fire, which doesn't do any good. Even without the back fire, you'll belch out a bunch of unburned fuel.
With the dashpot, the throttle takes about 1 second to close that last few degrees, and that's enough to burn up the fuel hanging around in the intake.
Just so you know, the purpose of a dashpot is to protect the exhaust system and reduce emissions. Particularly when cold, fuel clings momentarily to the intake manifold, before turning into vapor and entering the cylinders. At steady state this makes no difference; cold fuel is depositing and evaporating at the same rate. But if you jump off the throttle, the air flow suddenly drops to almost nothing, but the fuel is still evaporating inside the manifold. This suddenly enrichens the mixture, which will not ignite in the cylinder, but may ignite inside the hot exhaust system. Producing an exhaust back-fire, which doesn't do any good. Even without the back fire, you'll belch out a bunch of unburned fuel.
With the dashpot, the throttle takes about 1 second to close that last few degrees, and that's enough to burn up the fuel hanging around in the intake.
Last edited by scope103; 01-29-2014 at 09:44 AM.
01-29-2014, 05:23 PM
#4
appreciate info; if it isn't OEM on 22RE, 1987, then I guess forget about it, although the next reply is interesting as to what this gizmo does, dealer shows something but didn't differentiate between stick or auto T.....probably a deciding factor I guess...mechanic doing engine swap said it was missing...who knows...will go to junk yard and hope to find one, Ebay had a complete manifold with it for 87 22RE but got sold; will be open to options
thanks guys,
thanks guys,
01-29-2014, 08:55 PM
#6
Registered User
Don't really bother with this one. I've used up 2 of them (the springs and the cylinder fail). I've driven with it off, just with a manual it makes for a very jerky deceleration. If you have an A/T don't even bother then.
I think they are standard on the 3VZE's past 89, every single one I've seen in the yards had one.
I think they are standard on the 3VZE's past 89, every single one I've seen in the yards had one.
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