I have a 86 iroc with the 700r4, what controls the shift points for the car. Does the ecm or is it all mechanical. It seems to me that the ecm would control the shift points in the car but I could be wrong. If its not the ecm then how does the car adjust the shift points at different throttle angles. I mean the car is going to shift quicker if you only have say about 30% throttle angle than if you have 80% throttle angle.

I see that there is a governor pressure sensor, what does it do and where does its sensor data go to?

 

The Throttle Valve Cable (TV Cable) controls shift points - there is a tech article on adjusting it. There is no computer control on a 700R4.

 

So whats the governor pressure sensor? and what does it do?

 

Where did you see that the 700r4 has a governor pressure sensor? The 700r4 is all mechanical other than the convertor clutch. Shift points are adjusted using spring pressure, governor pressure, and throttle valve pressure.

 

You can also use a "Shift Point Kit", which has weights and springs that are used to tune the shift points. B&M has one, probably others also available.
Bill

 

The TV does NOT control the shift points. Nor should it be used to do so. The TV adjust the LINE PRESSURE according to the throttle position. The governor controls the shift pionts mechanically. But is does it in conjunction with the throttle imput/ line pressure. The governor works on mechenical/inerta and is affected by road speed. The weights and springs are the determining factor. If a higher shift speed is needed, then use a lighter spring on the governor. B&M kit works well, but alot of trial and error is needed to get it where you want it. There are 2 weights and 2 springs on the gov. You can mix and match them to adjust. With your stock spring pair and the 4-5 sets tha kit comes with, you have alot of possibilities. Always try the springs 1st B4 moving on to the weights. If you have alot of time, you can grind off material from the weights to acheive a lighter weight and a different shift point. This would be last resort. Getting another couple of governors off junk cars is a good start too. That way you have a backup..your stock one can be saved. There is not 'handbook' on what works in whar RPM/MPH range. It all depends on vehicle weight, stall, gearing, etc. Also, the governor is accessable from the outside, making an easier task. The round cover is like the one on the TH350s. The TH350s have an additional clip as protection for it to stay in place. The 700R4s did not come with a clip but you can see a hole for it on the bottom base where it would go. IDK why they ommited it for the 700R4. But get one from a TH350 and it will fit. I reccomend getting one if you intend on trial and error Governor tuning. Its just a safety measure since you will be slipping the cover on and off so many times. The B&M kit comes with a new o-ring. But you might want to get another one. Take it with you and match it up. The springs and weights arre the same on a TH350 and 700R4 BTW

 

Do all 700R4s have the hole(s) for the retainer clip, or is it just the early models? (I suppose I could look under my car...)
Bill

 

all do. I have a 86 but it has a 88 tranny. Both had it

 

That is very good to know.