Anyone here have a noticeable improvement in how their truck idles after doing an emissions delete?

 

The CA smog visual test tricks in that old thread are okay for a quick and dirty fix but might not all be really necessary....

Redline sells a smog legal kit for 1980 and earlier 20R, K8747, that comes with an adapter to mount the stock air cleaner on top of the Weber. You should just buy a smog legal Weber 32/36; it will make your life simpler. But you should be able to buy the adapter separately if you don't want to buy the whole kit.

The big hose that goes into the air cleaner base is actually the exhaust manifold air pump intake. The air pump needs filtered air to reduce wear on the pump just like an engine. The PCV valve connects to a port in the intake manifold. Putting a filter on the end of the PCV hose nullifies the PCV. I don't know how the smog check computer does it, but it does check the operation of the PCV. So you would probably fail the operating test not the visual. The other valve cover vent connects to the air cleaner lid.

I suppose a lot of people delete the egr valve to clean up the looks in the engine bay but if you're leaving the valve there for the visual inspection, you can just disable the valve by blocking the vacuum hose at the top of the valve. Just stick an appropriate sized bb in the hose and no one will know. BUT! I don't know how the smog check computer does it but they do check if the egr valve is working so you could/would fail the operating test, again. Also, as I understand it, there really is no reason to defeat EGR. EGR only occurs during steady-state cruising when you don't really need power. Under WOT, the EGR valve is closed.

The poster in the older thread might have passed smog check with his mods but I don't see how since even though his truck may have passed visual, it should have failed the operating test.

 

For your rough idle question, just increase your idle rpm a tiny bit by turning the idle speed screw?

 

I appreciate all the info! Thank you very much for taking the time. More for me to think about.

I wanted to also clariify that the truck idles smooth in Park or Neutral, but as soon as I shift into Drive it idles very very rough.

 

I'm no expert on automatic trans (Assuming this since you said "Drive" and not 1st/2nd gear) but might be worth checking vacuum lines, someone said this somewhere else so take it with a grain of salt, or two perhaps.

 

Could be some shot out mounts causing the bad vibrations.

 

Hoping someone here can help me out with carburetor choke info. Stock 20r Aisin carburetor with what I believe is called "automatic choke". It's the one that uses engine coolant to make a coiled spring tighten or loosen to adjust choke.

Anyway, I'm finally taking things into my own hands and taking shit apart to see what's what. When I've got the top half of the carburetor pulled off (is that whole thing called the choke?) am I correct in thinking that the coiled spring tension should be set so that the butterfly valve is fully closed?

When I reattach the choke to the carburetor, there is a little arm in the back that has to be hooked back in and secured with a clip. As soon as I attach that arm, my choke opens back up about 1/4 inch, cancelling out the adjustment I made to the spring tension. Is that supposed to be happening? Also, what specifically is the job of that little arm?

The reason I'm messing with this stuff is my truck doesn't want to start right up when I turn the key. Often takes 4 or 5 seconds and some gas pedal. I'd love to get it to start right up and I suspect the choke is the problem.

Aprreciate any help!