I changed my injectors this week to Bosch III, 22lb injectors for my 91 B4C 350 TPI... I did the coolant bypass mod at that point. I just used a length of heater hose, non molded. I even changed teh upper radiator hose. The car does run better, but it wants to get hot pretty quick. I drove it up the grade near my home, and it got really hot and went into limp mode. As soon as it cooled down, and I got to level ground, she cooled down. I bought a 160 degree thermostat, but havent installed it and probably wont after reading a few posts on the subject...think I'll take it back and get a 180. Could that bypass hose be sucking together and causing my overheating issues? Ive overheated on that hill before, but thought it was because my injectors were causing it to run hotter (this according to Jon at FIC). My fan is running on a switch, so its on as soon as I run the car for 5 minutes, or when I start the car if it hasnt completely cooled...but its a single fan, not a double.
HELP

 

did you bleed your cooling system after doing the bypass? you may have water trapped in your system if not.

 

My guess is you have air in you system and the incline forced it to the coolant sensor. I don't think the throttle body bypass sees that much coolant to overheat even if totally plugged. Are you talking about your b4c or about the TB car? The b4c should have 2 fans and the TB car shouldn't have coolant to the TB.

 

My B4C is the car Im talking about. And it only has one fan. The dual fan setup was busted up and not working, so I swapped out fans with the TB car. I havent swapped them back in at this point...had to JB weld the fan brackets...want to just get a new dual fan setup from summit, but $$ constraints havent let me yet.

 

This is an obvious answer, but did you check your coolant level after you did the bypass? Jack the front of the car up or park on a hill so that the coolant goes to the back of the engine. Then, when the car is cool, take off the cap and check the level. Start the car and let it warm a little. When the coolant level looks like it is about to overflow, have someone hold the gas pedal down. This will suck more coolant out of the radiator. As the gas pedal is held down, add more fluid in and cap the radiator. This should "pack" the coolant system and burp out any air caught. Do this multiple times after driving around. If your overheating is caused by air in the system, this might help.