318is increasing idling rpm (cams)

[kevo]

how do all,
i've put some cams in my 318is rally car a while back and the idling duly suffered which is no real problem, i altered the screw on the afm to compensate slightly which gave the effect of raising the idle slightly and solved the problem. however i now have altered the exhaust system and the idle now seems to struggle again, it stalls when cold and if you're giving it beans when you drop off the revs it can sometimes stall again, i've tried to increase the idle speed again in the same manner but it doesn't seem t work, is there anything else i can do as during rallies the car will stall if i allow the rpm to drop too much which is no good. i did think about altering the spring in the afm a click one way or the other but would like to try and find out more first. any thoughts
Cheers
Kev

[DHFiS]

I thought the idle speed was controlled by the electronics that run the fuel injection. When the TPS tells the car's ECU the throttle is shut the electronics run the car at idle.

BrianMoooore will have the answer.

[oakey]

Have you had the car remapped for the cams?

[kevo]

the car has had a remap, however the cams were fitted at a later date, (an impulse buy). they run fine in the car and make an improvement. the cams have been in the car about 6 months and i altered the exhaust last week, so it's not as though they should stop the car idling properly although they certainly could be made to perform more efficiently if i had it mapped again, unfortunately my bank account laughs at the suggestion.
cheers
Kev

[bruvs1]

I take it theres no air leaks anywhere from the TB and ICV - you've probably checked. Could you use the throttle stop screw on the throttle body to get you by?

BTW, when i put the cams in my mates engine, etc, etc, i chucked the throttle heater plate, all those silly hoses, heat exchangers and the idle control valve in the bin, i then wound in the throttle stop screw to get it to idle and then took it for mapping.

[tim_s]

use the screw on the TB kevo!

[Brianmoooore]

First point is that the screw on the AFM is for setting idle CO level, and doesn't have anything to do with idle speed! If adjusting this manages to raise or lower the idle in any way, the effect would immediately be reversed by the ECU via the idle control valve.
The idle speed is controlled electronically and isn't adjustable, other than by software changes, although you can force the idle up by screwing in the throttle butterfly screw on the TB.
Although this will increase the idle speed, it will vary with engine load, as the ECU will no longer be able to control it, other than preventing it falling below a minimum level.
The throttle position switch would also need to adjusted to track the adjustment of the throttle stop, to ensure that the engine still idles on the ECU's idle map.
If you really need a slightly higher idle speed, then the best way to do it, (once you've managed to reset the other adjustments to where they should be!) is to fit a link to the small socket beside the ECU to fool the ECU into thinking that aircon is fitted and switched on.

[gareth]

If you really need a slightly higher idle speed, then the best way to do it, (once you've managed to reset the other adjustments to where they should be!) is to fit a link to the small socket beside the ECU to fool the ECU into thinking that aircon is fitted and switched on.

brian, don't suppose you can describe this socket can you? I'm trying to sort my idle (here: http://www.e30zone.net/modules.php?name ... 15#1431615 ) but with no real joy so far. I only ask this as my plug is likely to be in slightly different place as it's a M30 loom.