Discussion
Broken red wire on the tps was causing lumpy running at idle, fixed and setting the tps back up and it's reading 4.3v at idle going to 0v at full throttle, according to all the articles this is the wrong way around. Tried every possible position but the only way to get it to read 0.32v up to 4.3v would be to flip the tps or position it on the other side of the throttle body - not possible. What am I missing? I have run it and the lumpiness when not accelerating has gone but it has always fluctuated between 1000 and 1800 revs on idle which might mean the tps has been wrong for some time. Anybody experienced similar?
Yes indeed that does sound wrong.
How long have you had this car?
It might be that the previous owner obtained a pot and fiddled with the wiring.
Perhaps post up a photo including the pot and wires to the connector, so we can see the positions of the wires?
If they are the wrong way round, then it should be fairly simple to extract the pins/sockets from the connector housing and re-insert them the other way around.
Once it's going in the correct direction you can then set the voltage at idle to the correct value. Also the foot down enrichment should then work correctly.
How long have you had this car?
It might be that the previous owner obtained a pot and fiddled with the wiring.
Perhaps post up a photo including the pot and wires to the connector, so we can see the positions of the wires?
If they are the wrong way round, then it should be fairly simple to extract the pins/sockets from the connector housing and re-insert them the other way around.
Once it's going in the correct direction you can then set the voltage at idle to the correct value. Also the foot down enrichment should then work correctly.
Thanks Adam. Probably only had the car running for a couple of months last summer after full resto. You might remember the no spark bad ECU earth thread. It seemed to be running well apart from the fluctuating idle but never having driven one before it might have more potential. Photo attached. I've tried swapping wires red to yellow but made no difference. Apart from the solder I've just done, the pot seemed original and untouched Lucas. 
A TPS is a variable resistor, nothing more.
The PCM sends 5 volts to one end of the resistor, the other end goes to ground and the signal is taken from the middle and sent back to the PCM.
So say that pin 1 is the 5 volts, 3 is ground and 2 is the signal return. As the wiper is turned to the right the voltage on pin 2 will fall.
Connect pin 3 to the 5 volts and pin 1 to ground and turn the wiper the same way the voltage will now rise.
Put an ohmeter on the 2 outer wires on your TPS and operate the throttle. If the resistance stays the same you have identified the 5 volt and ground pins.
These are the wires you need to swap.
The PCM sends 5 volts to one end of the resistor, the other end goes to ground and the signal is taken from the middle and sent back to the PCM.
So say that pin 1 is the 5 volts, 3 is ground and 2 is the signal return. As the wiper is turned to the right the voltage on pin 2 will fall.
Connect pin 3 to the 5 volts and pin 1 to ground and turn the wiper the same way the voltage will now rise.
Put an ohmeter on the 2 outer wires on your TPS and operate the throttle. If the resistance stays the same you have identified the 5 volt and ground pins.
These are the wires you need to swap.
Gassing Station | Wedges | Top of Page | What's New | My Stuff