Mike1alike
Established member
Fiat Punto mk2 1.2 8 V, I'm experiencing some idling issues. I've identified the cause being faulty throttle positioning sensor and I'm making this post about it because I've not seen many posts providing a solution in this case, but I have seen this problem described multiple times. This is one case.
Current issue is engine is revving by itself, especially when it should idle, but also while driving and in gear. The TPS gives erratic data, value moves by itself without touching the throttle pedal.
So, with MES connected, throttle positioning is bogus and not stable value. Pedal untouched, reading is 5⁰, 8⁰, 9⁰ - just dancing around those numbers. When pressing down the pedal the value changes but again, it does not reflect the real position. I think it went up to max 19⁰ although the pedal was to the floor.
What bugged me in this case was that even with the TPS unplugged there was still a bogus reading. Lower than with it connected but still bogus, was dancing around 2.x⁰.
I've also put some wires in the plug to measure the voltage and had the feed 5 V and the signal voltage 1.20 V on closed throttle to 1.40 V when opening. Normal values should be ~0.5 V closed to ~4.5 V opened.
I ordered a new TPS.
Found the code is 71738921, although Fiat gives no code for this one, nor for the Idle Air Control Valve.
(The IACV code is MEAT & DORIA 84055, FISPA 87046, HOFFER 7514055, MAGNETI MARELLI IB0100, SIDAT 87046)
I ordered the Magneti Marelli TPS. Unfortunately, I didn't find to order here the Ricambi Originali one, would have preferred that as I see it's a set including new screws and new TB gasket.
Never replaced the TPS. From pictures I see it has a holding mechanism resembling to the IACV's, that one I've replaced. It's some sort of starry spring.
Current issue is engine is revving by itself, especially when it should idle, but also while driving and in gear. The TPS gives erratic data, value moves by itself without touching the throttle pedal.
So, with MES connected, throttle positioning is bogus and not stable value. Pedal untouched, reading is 5⁰, 8⁰, 9⁰ - just dancing around those numbers. When pressing down the pedal the value changes but again, it does not reflect the real position. I think it went up to max 19⁰ although the pedal was to the floor.
What bugged me in this case was that even with the TPS unplugged there was still a bogus reading. Lower than with it connected but still bogus, was dancing around 2.x⁰.
I've also put some wires in the plug to measure the voltage and had the feed 5 V and the signal voltage 1.20 V on closed throttle to 1.40 V when opening. Normal values should be ~0.5 V closed to ~4.5 V opened.
I ordered a new TPS.
Found the code is 71738921, although Fiat gives no code for this one, nor for the Idle Air Control Valve.
(The IACV code is MEAT & DORIA 84055, FISPA 87046, HOFFER 7514055, MAGNETI MARELLI IB0100, SIDAT 87046)
I ordered the Magneti Marelli TPS. Unfortunately, I didn't find to order here the Ricambi Originali one, would have preferred that as I see it's a set including new screws and new TB gasket.
Never replaced the TPS. From pictures I see it has a holding mechanism resembling to the IACV's, that one I've replaced. It's some sort of starry spring.
