Idle Adjustment

[wllgmr]

How do I adjust the idle on my 02 s4? It is fuel injected. The bike idles around 1 and just under sometimes. Thats too low, right? I assume it is, because it stalls @ stop lights sometimes.

[Wanwo]

Is it only stalling when the engine is not up to temp?

[wllgmr]

It stalls after the engine is warm.

[Wanwo]

Do you have a non-standard exhaust? Air box modification? Any ECU changes? Lighter flywheel?

[wllgmr]

Full Termi, open airbox, Preformance ECU, Power Commander.......... I just got it back from the shop. Dyno, custom mapp. Everything is straight except the idle. Can it be adjusted without going back to the shop?

[Wanwo]

In that case take it back to the dyno shop. Their responsibility if you just got it back and it's not right. I know with my PCM3 it can adjusted by hooking it up to a laptop but I haven't had the need to learn how to do that yet.

On the other hand, might it be a matter of getting use to it? Maybe it was idling a little high before. My 8 idles about 1k when warm and I haven't stalled it in a long time.

[Speeddog]

Idle speed is controlled by the air bleed screws.

S4 won't be very happy with idle below 1k, as you've found.
Should be up around 1200 or so.

[wllgmr]

Where do I find these air bleed screws Speeddog? I like fixing whatever I can myself.

[Speeddog]

Where do I find these air bleed screws Speeddog? I like fixing whatever I can myself.

Rear throttle body:




Front throttle body:




Wind them out 1/4 turn each, see if that pulls the idle up.

If that's not enough, try another 1/4 turn each.

[wllgmr]

Damn right speeddog, thats great. Pics are much better than a written decription. I'll try it tomorrow. THANKS!

[DrNo08]

I hope this fix works for a 695 cuz I'm having the same problem.  I have to leave the choke on just a bit to keep it alive.

[DrNo08]

What would happen if only the front screw or only the back screw were adjusted?

[Speeddog]

What would happen if only the front screw or only the back screw were adjusted?

That would change the sync.

Whether it's better or not would depend on how well it was synced prior to turning the screw.

[Keith]

Actually that little screw to the right of the air bleed in the second picture should adjust your idle w/o any risk of sync issues.  That screw should limit the amount that the thottle cam can close.  It should push on a small tab behind where the throttle cable hooks in.  Try moving that screw in about 1/8 of a turn.

Good Luck,
Keith

[Speeddog]

The throttle stop screw will indeed effect idle with little chance of changing the sync.

BUT, it alters the mV reading of the TPS that the ECU gets, so it isn't the best method of adjusting idle speed.