dimitri

Does anyone know the travel distance of the plunger rod (for lack of a better term)of the dashpot used in the 1995 4runner with the 3VZ engine?

On mine, the dustboot is cooked solid and it can't move very much. I'll break it off to restore movement but Id like to know how much it's supposed to extend/retract.
Thanks,
D

HappyCamper

if it's in too much, then your idle will be high because it's not letting it go all the way down. if it's in too little, then you'll backfire when you let completely off the gas at high rpm.

scope103

The dashpot "throw" is adjusted base on engine rpm, not distance.
http://personal.utulsa.edu/~nathan-b...93throttle.pdf

dimitri

I looked at the diagram you linked to and what is being referred to as the dashpot (DP) (the "thing' with the removable filter and NO vacum line is what I am talking about.) Not sure how it "knows" RPM of any kind, but on mine, the plonger doesn't extend freely unless you help it with a screwdriver to pull out.

scope103

Then it's broken.

When you open the throttle, the dashpot should slowly (~1 second) extend (about 5mm). If you let go of the throttle, the arm lands on the dashpot, which holds the throttle open for about 1 second as it retracts.

Shady Cadence

The plunger should move in and out slowly. If it doesn't move, take it off, and the plastic cap on the back can be pulled off. You'll find a round filter element that just sits loose inside, take that out and you can see the vent holes for the air valves inside. If there's dirt or crud in those holes, try to clean them out with a computer duster. If they're clean, but the plunger still won't move, the shaft is probably rusted.

I'm not sure if it can be disassembled further, but it's currently a junk part, so you really have nothing to lose by trying.