The car was running like a dog today. I was messing with the TPS at the weekend to improve the cold start and idling, and I achieved that all right, it was idling at 1800 rpm when cold, but once warm the idle was all over the place and pick up was also poor. I had the car on a gas analyser and the emmsions were almost zero even with my cat in the garage (naughty, naughty) suggesting lean at idle. I got home balanced the TBs again and went to adjust the TPS. I must have moved it about 1/8mm and the idle immediately improved. I think I had the TPS set too low and the throttle too wide open on the throttle stop which gave a faster idle when cold but ran too lean when warm. When I went in tonight the warm idle was fine again and the TPS reading was 0.37 as it should be. I will see how well it runs tommorrow when cold. Any tips?
0.37 is right on the limit where the map goes from site 0 (no throttle) to site 1 - what's probably happening is the ECU is bouncing between the two.
and they are very sensitive - for instance, open the throttle then let it snap shut - take a reading - now open it again and let it go back onto the stop very gently - read it again - 99% of the time you'll get different values.
what you need to make sure it no matter how hard you let the throttle close, make sure it's always sufficiently below the site 0/1 threshold, so the ECU knows it's idling.
You have hit the nail on the head guys, I think the TPS was set up completely wrong. Previously the car would not idle at all when cold (I had to heel and toe for about 2 mins), and idled around 900 rpm when warm and the synchrometer readings were 3.5. There was also a very settled idle, but it was quite jerky on throttle. After some more mucking about it will now idle at 1500 rpm immediately from cold after a couple of blips of the throttle. The idle is now just under 1000rpm (should be 980 according to SBD) and the synchrometer is at 5.5 (as it should be). I think the throttle stop was set too shut previously which led to the sticking throttle noted by Rob, and poor cold idle due to no cylinder filling. I must have had the TPS set too high to compensate (it was around 0.39 previously) now it is 0.35 - o.37 as Rob suggested. The cold idle makes the car MUCH easier to drive, and I am now getting the rally car style popping and cracking on over run that I didn't get before. It is probably slightly more lumpy round town than it was, but in general it is much better. Thanks for the suggestions.