could my AFC be bad???

[nataku80]

ok for a while now i have been dealing with the bucking and hesitation that my car has been doing, because i didnt have enough money to get a TPS sensor. so last week i went to a junk yard and got like 9 TPS's. got home and none of them worked. some were worse than others. i could tell because on the AFC my throttle % would cycle up and down. if i held the throttle at 18% it would go to like 8% then cycle back up to 18% and then go to like 28%. it would always cycle up and down by like 10% sometimes it would go 15%. so i unhooked the TPS and went for a drive and it didnt buck or hesitate. but when i connected it back it came back. so i though "how n the hell could all these TPS be bad?

so today i went out and spent $109 for a new one, got home put it on and still the same thing. so whats up??

im thinking it could be my AFC? maybe its bad or something? i cant figure this problem out. help

 

[xioca]

Theres an adjustment on the TPS sensor. You can't just install it and go. As for your SAFC being bad try it on somebody elses car.

 

[nataku80]

i know theres and adjusment on the TPS. i looked it up on vfaq and did it that way but it still wont work. so i busted out my datalogger, and it wont read anything on it. i dont know i guess ill figure it out on my own. thanks

 

[blcknspo0ln]

Go back and plug one of your TPS' in. Now go into the monitor mode of your SAFC and look for throttle voltage. At closed throttle it should read 0.0v and at open throttle it should read ~4.5v. You can also tell my just monitor throttle position percentage.

If all of the TPS' are doing the same thing as you say, then it would only lead to the TPS wiring, the SAFC wiring, or the SAFC itself. Trace the TPS wires back and see if there is anything suspect there. Same with the ECU (and double check that it is connected to the correct PIN), and then check if the correct wires are run from the SAFC harness (I believe TPS is grey). Another thing to check for is the actual male pins in the SAFC harness, I bent the TPS prong by accident one time and it took me weeks to figure out it was just the stupid connector.

 

[nataku80]

thanks for the good info i will try that out tomarrow and get back with the results.

 

[nataku80]

ok i tried what was mentioned above but still nothing. i checked wiring and all. the AFC is good i tested it on my talon. ok so i noticed this, when the car is on and running is when this happends, if i shut the car off, but turn the key to turn everything, but not start the car and push the gas it reads regular. but if i start the car fully it will bounce around like that. so im thinking what can mess the signal like that?

 

[steve]

Is this problem with the 2G NT in your profile?

 

[nataku80]

yeah but i have a 4g64 spyder, so i dont have the ecu, the regular GS has. im actually running a 97 GSX ECU.

so now im thinking about getting back to the basics to try and find what is causing this problem. so to start what is everything that would cause it to hesitate and buck, at idle and while cruising? anytakers it will be like house, the tv show.....

 

[steve]

Just making sure. So this is really a 4G64T Spyder, correct.

The SAFC has a sensor check screen that shows you the voltages from the TPS and blue wire. Are they jumping around too? Are you getting s CEL?

 

[nataku80]

yeah its a 4g64t, its nice to have the torque on hand and my small 16g spools quick.

ok now with the car turned on but not started, the sensor check for throttle reads as follows

o.700 and cycles up to 0.705 and down to 0.690. and when its setup to monitor the thrttl reads 0.0%

and if you start the car things change

the sensor check mode will read 0.745 and cycle up and down to 1.025 and hit things inbetween. and the monitor setting it will jump to 10% and cycle down to 5.0% and 0.9%


it will stay at 0.0% for a lil bit

i cant figure this out at all