I have a tbi and converted to a carb. I have a torque converter lockup by b&m that replaced the stock lock up from the computer and a transmission cooler. The transmission is a 700R4 and was rebuilt less than 10,000 miles ago. The car after running 15 min or so will not shift into 2nd until 4,500 rpm. I have adjusted the TV cable and I don't know whats going on. Also, 4th will not always shift until I reach 70 or so. I guess my question is, whats going on and how much slack should be on the TV cable because I have a good 1/4 inch.

 

There isn't an actual proper slack, its different for different cars. Just use the setting instructions in your manual.

 

You probably don't have the cable geometry correct. The radius of the throttle arm mount, distance from bracket to throttle arm, and the angle at idle all have to be right before you can expect the transmission to behave properly.

 

What kind of bracket did you use? I used a holley bracket and it work perfectly.

 

There are numerous other threads in this forum that all address this same issue, and again I will relay to you the correct TV (throttle valve) cable adjustment:

To follow are the symptoms of a misadjusted throttle valve (TV) cable, along with the correct adjustment procedure for 700-R4 & 200-C trannys, that I originally gave to someone else in this forum.

The purpose of the TV cable (to the trans) is to tell the tranny how far the accelerator has been depressed, to assist it in knowing when to upshift (or downshift).

If the TV cable is not pulled far enough (out of the cable housing) during acceleration, shifts will occur too late. (The tranny "thinks" the accelerator pedal is not depressed as much as it actually is.)

If the TV cable it is pulled out too far during acceleration, shifts will occur too early. (The tranny "thinks" the accelerator pedal is depressed more than it actually is.)

The TV cable housing is supposed to terminate at a bracket at the carb (or throttle body, if so equipped): the end of the cable itself is connected to the throttle valve lever on the carb or throttle body.

To adjust proper TV cable tension:

1) Depress the spring-loaded tab (mine is goldish-colored) located on the housing bracket. (See attached photo) When this "button" is depressed, pull the cable housing back (towards the firewall) as far as it will go - (you will hear "clicks" as the housing pulls back through the lockdown mechanism). This will pull the cable to maximum extension/tension/travel (which fully opens the throttle valve in the trans).
2) Then, simply get in the car and slowly press the gas pedal (engine off) all the way to the floor. This will allow the cable/housing to "self-adjust" to the correct position. The idea is to have the cable pulled just to the end of its travel at WOT.

Don't stomp the gas pedal - just press slowly. Stomping the pedal may result in the housing being pulled back (towards the carb/throttle body) too much, resulting in late shifts again...

This entire procedure doesn't cost anything and it only takes 5 minutes - and that's only if you screw around for three!

Hope this helps...

(The tip of the pencil in the attached photo indicates the spring-loaded tab you press in to allow you to pull the TV cable housing back to fully extend the cable)

 

Also:

I totally forgot to mention my response that if you have "1/4 inch of slack" in your TV cable, it is obviously too loosely adjusted: i.e. - the cable is not being pulled out of the housing enough at any time to properly "inform" the trans. how far you've got the gas pedal pressed at any point during acceleration..

Once again, the object is to have the cable pulled out to the end of its travel at WOT. All shifts at any other speed will then occur at the pre-designed points for that valve body set-up.

This fully accounts for your "late shift" problems...