Ill be switching to carb in a few weeks due to a new engine Ill be dropping in my 88 T/A. The threads that i've been reading state that because of the switch the lockup in my 700R4 can no longer be used. Is this correct and if so what is the reasoning behind it?

 

The computer depends in part on the input from the throttle position sensor to decide when to lock the TCC. Without a working computer system, you'll have to provide another means of controlling the TCC.

 

https://www.thirdgen.org/forums/carb...up-budget.html

 

https://www.thirdgen.org/forums/carb...c-control.html

 

So just because the throttle position sensor is gone that means the computer wont know to lockup? I thought as long as you keep the full harness inside the car it would still lockup when you put the tranny in O/D. I thought this was gonna be a easy swap from TBI to carb.

 

The ECM needs a lot more information than just what gear it's in to decide when to lock up. Input from the CTS, TPS, and MAP is used, as well as the 4th gear clutch switch.

Even still, it's not so much that the computer won't lock the TCC, it's that without all the sensors working, the computer won't try to carry out any of it's functions, including TCC control.

 

You just need to
1) test your trans switch according to the TCC article I linked above and see if you can rig a toggle without dropping the pan (see if you have the right solenoid switch in the tranny already), and if not, then

2) buy a lockup kit, drop the pan, and install - it's not difficult to do, it's time for a fluid/filter change anyway, and gives you an excuse to do a shift kit while in there.

Make sure you take care of the rest of the carb swap correctly as well - which is fuel pressure (a return-style regulator), geometry corrector for the linkage on your chosen carb for the TV cable, good sturdy throttle cable brackets, and vacuum advanced distributor.

Everyone wants to think swapping to carb is easy - it's not. Easy is the LSx and "tuner" world - aftermarket has plug 'n play everything, just plug it up, and upload a driver for it like your home pc, and off you go - but it also costs alot, and although they make impressive numbers, it's just not American Muscle! Us carb guys like 'mechanical' over 'technical' - we like to get our hands dirty, we like to turn wrenches, not plug into USB ports.

 

What Carb are you going to be using?
Buddy of mine went carbed on his 87 K10 P/U, and got a kit to install a TPS on his carb (Holley) and left all the sensors hooked up, sans o2, and runs on that. Locks up at 38mph in 3rd, and 4th.

 

test to see what switch you have. if you have the correct switch according to the tcc sticky then you dont have to drop the pan. put in a vacuum switch the way described and call it done.

 

There's been talk about that, but I don't remember anyone having done it on a thirdgen. I don't really see how it could work, but maybe it would.

 

Im going to be using a 650 edelbrock thunder series. And I was gonna use a msd pro-billet mechanical distributor, not a vacum, with a msd 6AL box. Thats fine to use the mechanical one right, i didnt think anything of it. And as far as the fuel pressure regulator I was gonna use just a inline one for the gas line and not worry about the return. Id rather find out about the potential problems now rather than when its in my car. So any help is appreciated.

 

You'll want a distributor with vacuum advance. A deadhead regulator will burn out a stock fuel pump, you'll need one with a return line.

 

Thanks for the heads up Apeiron. Why is it better to run a vacum dis. instead of the mechanical one i was gonna use though?

 

Vacuum advance gives you additional advance in addition to the centrifugal, so that you get better part-throttle performance and mileage, and less plug fouling.

 

Yea, I found this thread that explains everything about it. http://www.pro-touring.com/forum/showthread.php?t=29320 I went onto summit and changed my order to a vacum cause it will be a DD. Hopefully itll be a easy engine swap with few problems. One can only wish.

 

And also, back to my original topic, without the lockup until I install the kit from TCI, would the car be more prone to overheating without the drop in rpms?

 

Your transmission will be hotter, especially in O/D, but you most likely won't notice a difference in engine temperature.

 

a holley with the tps with everything else hooked up works on the 93 S10's with 4L60E's and isn't always necessary for anything older but I have a feeling that's a completely different computer to the third gens, worth a try though?

 

With a 4L60E the PCM already has a whole lot more work to do to control shifting. The ECM in a thirdgen is a more primitive animal.

 

just check the solenoid in the tranny to see if it is the correct one in my post above. if it is about 2 hours, some minor wiring, and a 20 dollar switch will control the tranny lock up. simple. or put in a toggle switch on the datalink connector and call it a day.

 

saving info