Tickover variation help please

[Toby Tram]

This one is beyond my current understanding!

I've just been for a fairly spirited hoon. On the way back I went through a built up area at 30 for about 1.5 miles. Then I had to stop for a level crossing. The tickover was sitting just above 1500rpm which is a lot higher than normal. I let it sit at that for about 1 minute then turned on the fan via the auxiliary switch and the tickover dropped back down to a normal level. Not that I know what that normal level is because the rev counter doesn't register at lower revs!!

Any idea why it would drop like that. I turned the fan off soon after and the revs stayed at the normal level.

I have often found in the past that the revs will be a bit high if I come to a stop but they will drop back to normal after a few seconds.

Adi

[jmorgan]

Whatcha got, flapper or Hotwire? I am on a hot wire and sometimes it gets a little finicky, the stepper (Hotwire) is often cited as a culprit but when I check mine it is clean. Though started to use ptfe to seal it an think there may be an improvement.

I do check the throttle pot voltage and the throttle returns to rest correctly.

Edit. Oops. Not reading your description proper.

Edited by jmorgan on Saturday 3rd May 08:56

Edited by jmorgan on Saturday 3rd May 09:11

[mrzigazaga]

Does sound like something is sticking mate..Do you have two throttle return springs on the throttle housing?..Idle control valve could be gummed up..Just make sure that if you do take it off then it has to be sealed properly...1500rpm sounds a bit high...Ziga

[simonwedge]

Adi

Mine used to do exactly the same. Try disconnecting the vacuum advance pipe on the distributor and see whether that makes any difference. In the end I ran mine with the pipe disconnected all the time (also helped with the pops and bangs on the overrun :-) )

[Toby Tram]

Thanks Guys

It does have the flapper system......apparently! Having only had it for a year I can't say I'm particularly familiar with it because I haven't been able to find much time to mess about!

Didn't get the impression is was the return springs as usually you can blip the throttle and it will settle down.

Pops and bangs on overrun are just about right at the moment. Although I did leave at 7am this morning for my hoon and my neighbour said that he didn't hear me!!!! Damn!!!!!!!

A.