hi there chaps,

after a question that i put on omega24v6's thread the other day i was advised that tweaking the idle screws would help with the idling rev, and should hopefully bring them down slightly,

i've had the car out just now and turned the screws fully clockwise! and it hardly changed the revs at all! i have turned the throttle adjustment cable so it doesn't even touch the throttle linkage. and the car is still turning over at 1200rpm! and the AFR is still 12:1 i have reduced the req fuel from 18.0 & 9.0 to 15 & 7.5 and tried to reduce the figures on the ve table when the car was up to temperature. my warm up wizard values seem to work well and the car starts up straight away but i cant get the idle to go down. MAP value is 60kpa, whether that helps or not im not sure, car is currently set up on alpha n

surely if the idle screws are fully clockwise and the throttle cable adjust is not touching the car should surely stall? im at my wits end!

please help

[Edited on 1/12/08 by omega0684]

Are you able to carry out a carb balance, maybe the first butterfly is shut and not the rest.
Mine was hunting around and triggering the accel adjustments(they were set very fine) a quick balance and I had to readjust the idle and it's rock steady now.

ATB Dan.

i have carb tune 4 pro, so i can do carb balancing, i checked them before and they were pretty much the same or within the % difference recommended by the carbtune manual.

also, how do you make sure that all the butterflies are fully closed at idle? how do you adjust them so that they are?


[Edited on 1/12/08 by omega0684]

Are you using MAP for your VE table?

Edit: sorry just re-read... ALPHA-N

Air leak after the TB's?

[Edited on 1/12/08 by GregSL75]

Ive had all the TB's off and cannot any air leaks anywhere. ive put new jubalee clips on to make sure they were ok,

How about your manifold gasket?

Worth a look because unless your TB's are knackered your getting air in somewhere.

Do your T. bodies have a extra air valve for cold start high idle? may be that is stuck open.
Steve.

[Edited on 1/12/08 by stevec]

Air is definately getting in somewhere - it's not a megasquirt problem. You can't get air down a wire, so it must be a mechanical problem. Probably one of the linkages or a gasket. Try spraying easy start around the manifold - when the idle shoots up a few hundred rpm that's where the air is getting in.

Good luck!

As already said check for leaks BUT also check that the balance is ok. Mines was out on one butterfly and even after balancing i could only acheive 2500rpm idle. However i recckon I had a bent butterfly and after a bit of tweeking it came down to 850rpm. If you've had the bodies off and apart for respacing then perhaps the butterflys are disturbed and not central in the bodies themselves. This would create a physical stop (butterfly to body) but allow too much air past hence the fast idle speed.