Joseph is now returned to rude health
Discussion
Well the saga is over, Joseph passed his MOT today!!!!!!!
Now the emissions are very interesting, on the first attempt they were 4.1%, maximum limit 3.5%. I had a good idea and removed the air filter for the second attempt which resulted in a reading of 5.04%. Then someone pointed out that the increased air flow would have resulted in an increase in fuelling. Damn not such a good idea.
Did a bit of research and found in 2009 Josephs emissions were 3.47% only just under the limit. I looked up Gerald’s emissions and for the last three years they were 1.68%, 0.737% and 0.762% so very markedly different to Joseph. So obviously there was a real problem. Had a think about it and called in Adrian Venn of Exactly TVR (adrian@ on here). He had a good look around and said what he thought the problem was, but doubled checked all the induction over. Cleaned all the electrical contacts, checked the plugs etc.
Then he checked the throttle pot BINGO his original diagnosis was correct. It was a replacement TP with gold contacts (originals had silver) and it had been fitted without the necessary wiring modification. Of the three contacts the two outside contacts are reversed on the gold compared to the silver He double checked by looking at Gerald’s connections and they had been reversed as a replacement TP had been fitted at some time.
To be doubly sure Adrian used the Star Tester and it threw up no error codes.
With the contacts reversed the TP was saying 'I think I'm on full throttle' at idle and vice versa, when just driving around 50% throttle it would drive fine. I guess the original excessive reading was due to the fact that the car hadn't being running much and we let it sit on tick over for about two hours prior to the MOT due to a completely kn
ed battery.
If anyone is interested either in the car or just wants more information just send me a PM.
Now the emissions are very interesting, on the first attempt they were 4.1%, maximum limit 3.5%. I had a good idea and removed the air filter for the second attempt which resulted in a reading of 5.04%. Then someone pointed out that the increased air flow would have resulted in an increase in fuelling. Damn not such a good idea.
Did a bit of research and found in 2009 Josephs emissions were 3.47% only just under the limit. I looked up Gerald’s emissions and for the last three years they were 1.68%, 0.737% and 0.762% so very markedly different to Joseph. So obviously there was a real problem. Had a think about it and called in Adrian Venn of Exactly TVR (adrian@ on here). He had a good look around and said what he thought the problem was, but doubled checked all the induction over. Cleaned all the electrical contacts, checked the plugs etc.
Then he checked the throttle pot BINGO his original diagnosis was correct. It was a replacement TP with gold contacts (originals had silver) and it had been fitted without the necessary wiring modification. Of the three contacts the two outside contacts are reversed on the gold compared to the silver He double checked by looking at Gerald’s connections and they had been reversed as a replacement TP had been fitted at some time.
To be doubly sure Adrian used the Star Tester and it threw up no error codes.
With the contacts reversed the TP was saying 'I think I'm on full throttle' at idle and vice versa, when just driving around 50% throttle it would drive fine. I guess the original excessive reading was due to the fact that the car hadn't being running much and we let it sit on tick over for about two hours prior to the MOT due to a completely kn
ed battery.If anyone is interested either in the car or just wants more information just send me a PM.
Edited by Gerald-TVR on Tuesday 19th April 21:59
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