I am building a pickup with an '85 2.3 turbo fuel injected SVO engine. It is running but pops and bucks when I push down the accelerator pedal much at all. It can be revved without too much popping when under no load. I have been told the timing should be advanced for a turbo beyond factory 10 degrees.
I am in the process of changing the Throttle Position Sensor since the test voltages did not come out as directed. When testing the voltages I got just 3 volts across the red wire and the ground. When I moved the + probe to the middle terminal that goes to the ECU, no voltage ever shows. ( Tutorial said 5 Volts across red to ground and then .9 Volts at the middle terminal at closed throttle.)
Now that I have replaced the TPS I get basically the same. I traced the wiring to the MAP sensor and I have 5 Volts there on the middle terminal which comes from the ECU but I get nothing coming out of the MAP sensor to the TPS. I bypassed the MAP sensor and got the 5 volts at the TPS but again, no reading at all from the middle terminal.
No matter what, if I place a digital OHM meter across the two outside terminals, or one outside and the middle terminal, I get no reading of resistance at all. And that is with the old TPS and the new one. Knowing OHM's Law, you can not have a voltage drop across any device unless there is a resistance. Does anyone know how these variable resistors are made and why there are no resistance readings from them?
I can not imagine that more than one new or old TPS are bad and will not read resistance. I read where the TPS is a variable resistor or potentiometer. I am assuming the MAP is also a potentiometer that is varied by atmospheric pressure changes.
I am using a rebuilt ECU from an 85 2.3 turbo FI. I also have an ECU from an 87 Turbo coupe but all the voltages are the same. So I don't think it is the ECU.
I feel that I must get this TPS matter understood and fixed before I will get the vehicle operating as a 2/3 turbo should. Any help will be taken seriously.
I am in the process of changing the Throttle Position Sensor since the test voltages did not come out as directed. When testing the voltages I got just 3 volts across the red wire and the ground. When I moved the + probe to the middle terminal that goes to the ECU, no voltage ever shows. ( Tutorial said 5 Volts across red to ground and then .9 Volts at the middle terminal at closed throttle.)
Now that I have replaced the TPS I get basically the same. I traced the wiring to the MAP sensor and I have 5 Volts there on the middle terminal which comes from the ECU but I get nothing coming out of the MAP sensor to the TPS. I bypassed the MAP sensor and got the 5 volts at the TPS but again, no reading at all from the middle terminal.
No matter what, if I place a digital OHM meter across the two outside terminals, or one outside and the middle terminal, I get no reading of resistance at all. And that is with the old TPS and the new one. Knowing OHM's Law, you can not have a voltage drop across any device unless there is a resistance. Does anyone know how these variable resistors are made and why there are no resistance readings from them?
I can not imagine that more than one new or old TPS are bad and will not read resistance. I read where the TPS is a variable resistor or potentiometer. I am assuming the MAP is also a potentiometer that is varied by atmospheric pressure changes.
I am using a rebuilt ECU from an 85 2.3 turbo FI. I also have an ECU from an 87 Turbo coupe but all the voltages are the same. So I don't think it is the ECU.
I feel that I must get this TPS matter understood and fixed before I will get the vehicle operating as a 2/3 turbo should. Any help will be taken seriously.