- Joined
- Nov 4, 2005
- Messages
- 4,335
i dont know where to post this ,but i know my bro's can help.my 1986 pontiac grand prix 2+2 ,5.0 v8,has a computer monitored/controlled quadrajet carb.
i got a code 21 which is a tps code,went to test tps(its located IN the carb)and unplugged tps plug to test for reference ground (good)and positive(5.0v),has both and i went ahead and tested output lead(just curious)and has 4.7 v there too!?remember i unplugged the tps,should not be any voltage on that(output to computer) lead,right?same readings plugged up. i need to take a quick look at a wiring diagram to see if another sensor could be causing voltage to "feed back" through computer.tried another computer and same thing.car completely stock.any guesses?link to a diagram?
i got a code 21 which is a tps code,went to test tps(its located IN the carb)and unplugged tps plug to test for reference ground (good)and positive(5.0v),has both and i went ahead and tested output lead(just curious)and has 4.7 v there too!?remember i unplugged the tps,should not be any voltage on that(output to computer) lead,right?same readings plugged up. i need to take a quick look at a wiring diagram to see if another sensor could be causing voltage to "feed back" through computer.tried another computer and same thing.car completely stock.any guesses?link to a diagram?