tii throttle body differences

[BillWilliams]

The pictures show the slight differences in the late and early sytle tii throttle bodies. The change was to make the CO adjustment more precise. Notice the bottom boss is different and appears to have provisions for an O-ring. I have not had that part apart, so I am guessing.

[TobyB]

Great pics- thanks!

So really, in induction terms,

this adjustment is the sync between

the fuel metering system (the pump

with it's cone, warmup, etc)

and the air metering system (the butterfly)?

Cool.

t

[BillWilliams]

However, the adjustment made by turing the small screw only changes the air part of the equation. So, effectively, it does change the air/fuel ratio.

Fuel changes to the on throttle ratio can be made in two ways, inside the pump or by the length of the linkages.

[jgerry2002]

More precise or just "less sensitive" to adjustments? It appears to be sensitivity thing, perhaps this can also mean precise.

Spent a couple hours attempting to dial things in with an old style TB (its the cleanest one I have) and a CO meter. The motor has a slight issue with idle hunting that I could not dial out.

[BillWilliams]

I think we are saying the same when we say less sensitive and more precise.

I dare not offer you assistance with the hunting problem. You know more about these tiis than most.

[SHEN]

My car was searching when it was warmed up. From what I remember I turned the small screw in till it searched more and then brought it back 1/2 turn adjusted the idle back down and it hasn't searched since. From what I remember turning the screw in leans it and turning the screw out rich ens it. Hope this helps at all. Solved the problem with my car.

[jgerry2002]

Well in my case, I found that another linkage end needs to be replaced (the one that I did not replace because the long rod has two right handed threads so I ended up one short when I ordered three left and three right). Basically the sloppyness caused the linkage to bind slightly which caused the idle to hang and in turn the CO would end up all over the place.

2nd issue, is that I need to swap for a late style TB so I can get more precision in the adjustment. I revisited my parts stash and one later TB I thought was bad was just badly gummed up. A few minutes in the cleaning tank, a good soaking with B12 chemtool, and some fine steel wool inside should render it very useable.

3rd problem is my thermostat is a 71C, too cold for this weather. My 75C did not arrive while I am upstate this week.

Probably won't get to retune the car until spring time though. I am happy enough the car starts ok at 40F and runs without any leaks.