Discussion
I guess the answer to this will probably be" Go and buy a new Throttle Pot" but thought I would ask anyway.
Started the S3 up this evening and it idled fine,drove about half a mile and it started to kangeroo a bit but stopped under acceleration and then started again when I took my foot off the throttle,when I stopped at traffic lights it died altogether but started again as soon as I turned the key.When I got it home and sat with my foot on the accelerator,holding it to about 1500 rpm it would rev up to between 2500 and then down to 500 without any movement by me on the peddle.Its now asleep in the garage but i would like to sort it at the weekend if its only going to be a trip to Uncle Henrys to buy a new Pot and gold connectors.
Started the S3 up this evening and it idled fine,drove about half a mile and it started to kangeroo a bit but stopped under acceleration and then started again when I took my foot off the throttle,when I stopped at traffic lights it died altogether but started again as soon as I turned the key.When I got it home and sat with my foot on the accelerator,holding it to about 1500 rpm it would rev up to between 2500 and then down to 500 without any movement by me on the peddle.Its now asleep in the garage but i would like to sort it at the weekend if its only going to be a trip to Uncle Henrys to buy a new Pot and gold connectors.
Sounds like The Throttle pot to me.
If u drop VODKAKID a mail he still might have a spare one i gave him a few months back, and as he was unfortunatly involved in a crash shortly afterwards he might still have it kicking about.could save you £40. His profile will probably be in the Griffith Forum somewhere.
All the Best
BB
If u drop VODKAKID a mail he still might have a spare one i gave him a few months back, and as he was unfortunatly involved in a crash shortly afterwards he might still have it kicking about.could save you £40. His profile will probably be in the Griffith Forum somewhere.
All the Best
BB
Cheers BB,
Thought thats what it probably was but needed confirmation.Being that Uncle Henry pays my wages (sucker) and that I need to get a new throttle cable after replacing my broken one with the spare I got when I bought the car.I will pop down to Ford at the weekend and get a new one along with the gold connectors,fortunatly I get a good discount so its not all bad news.
Dave
Thought thats what it probably was but needed confirmation.Being that Uncle Henry pays my wages (sucker) and that I need to get a new throttle cable after replacing my broken one with the spare I got when I bought the car.I will pop down to Ford at the weekend and get a new one along with the gold connectors,fortunatly I get a good discount so its not all bad news.
Dave
I had a very similar set of symptoms and after reading the bible it led me to change the throttle pot. The symptoms being that the car idled nicely but as soon as you tried to accelerate above 2500 RPM the engine almost died but just managed to stay ticking over.
After using Halfords best £19 diagnostic box, it told me that there was low voltage on both throttle pots and also the (new!!) throttle pot. Looking at the wiring diagram it showed that these three items share a common black/brown wire which goes to the ECU. On inspection the wires were all totally corroded throughout their length. I guessed at the time that it had to be a dodgy batch of wire as it would be too much of a coincidence for those specific wires to have corroded.
Ihave since spoken my local garage and he told me that due to the TVR being GRP the car's earthing points are all the more important. Basically if your earth straps (2 off I believe, one of them being the battery negative) are not absolutely sound then the earth return will use the cars wiring loom. It just so happens that the brown/black wire is the earth return and the cars loom is not man enough to take the current and hence causes severe wiring damage.
Anyway to cut a long story short, if the throttle pot is not at fault, check/clean your earth points then look to see if you have damaged any brown/black earth wires.
After using Halfords best £19 diagnostic box, it told me that there was low voltage on both throttle pots and also the (new!!) throttle pot. Looking at the wiring diagram it showed that these three items share a common black/brown wire which goes to the ECU. On inspection the wires were all totally corroded throughout their length. I guessed at the time that it had to be a dodgy batch of wire as it would be too much of a coincidence for those specific wires to have corroded.
Ihave since spoken my local garage and he told me that due to the TVR being GRP the car's earthing points are all the more important. Basically if your earth straps (2 off I believe, one of them being the battery negative) are not absolutely sound then the earth return will use the cars wiring loom. It just so happens that the brown/black wire is the earth return and the cars loom is not man enough to take the current and hence causes severe wiring damage.
Anyway to cut a long story short, if the throttle pot is not at fault, check/clean your earth points then look to see if you have damaged any brown/black earth wires.
Steve wondered when you'd get around to posting this, you forgot to mention the 2 air flow meters you changed as well 
.
Excellent tip for those that seem to have problems in the throttle pot area and change them on a regular basis. Check the main earth path first, it could be using the small earth returns through these three components to compensate for the lack of a decent main earth, sh*gging the wires all the way back to the ECU.
Harry
. Excellent tip for those that seem to have problems in the throttle pot area and change them on a regular basis. Check the main earth path first, it could be using the small earth returns through these three components to compensate for the lack of a decent main earth, sh*gging the wires all the way back to the ECU.
Harry
Cheers guys,thats another thing to check then,havent fitted new pot yet as I havent got round to getting one hopefully this week if I get time.The main reason I think mine failed is that I took the car for a swim on a very flooded road the day before it decided to go wrong.When I disconnect the Throttle pot it idles ok which is why it leads me to believe thats the problem.
Can you drive the car without the T/P connected.
Can you drive the car without the T/P connected.
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