82 F150 351 7200VV

The throttle position sensor is reading a little high. About 2 volts at throttle close....about 6 1/2 volts throttle wide open. What effect does this have on carburation? I'm thinking the EEC III would richen the mixture but then would the O2 sensor read that and send a signal to lean the mixture back? Creating a fluctuation that would cause rough idle? LOL You can tell I'm not an engine expert! I sure would appreciate the answer though! Thanks.

Mark

 

I'm not an expert either, but I'll share what I've learned about EEC-III. I don't know of any voltage specs for the TPS on EEC-III vehicles. The only information I've found so far is measured in ohm's resistance.

See how these ohm's readings compare with your voltage measurement:

Throttle Position (TP) Sensor
Closed Throttle.... Org/Wht-Blk/Wht.... 3000-5000
Closed Throttle.... Dk Grn/Lt Grn-Blk/Wht.... 550-1100
Wide Open Throttle.... Dk Grn/Lt Grn-Blk/Wht.... More than 2100

From what little information is available about EEC-III, I've gathered that at WOT there is no thermactor air injection and the carburetor goes to the richest mode. (The carburetor feedback control motor (FBCA) operates a plunger with a needle valve on the end of it. The needle valve controls the pressure in the vacuum chamber of the carburetor. More vacuum = Lean, less vacuum = Rich.) I think WOT shuts off EGR as well.

Scott