Rough idling.

[Grumps]

Mine idles better now i've ditched the Induction kit (K&N type) and gone back to the original air box with a new air filter

It has got a K&N on it so maybe that's the cause.

 

[Paul Rice]

Don't recognise a drop in performance, kept up on Sunday?

 

[smiffy]

My earlier post it transpires was slightly misleading. Having not spent much time under the bonnet since buying the Zed, I thought I'd better practice what I'd just preached. So, this afternoon I thought I'd tackle my very own random misfire on idle and I needed to test my newly aquired diagnostic software!

So, bonnet up, check P codes, clear the "Crankshaft Sensor" error. Software works!

Next, clean the throttle body. WTF! TWO throttle bodies in line? This where my earlier post was misleading, you have to remove the first throttle body (called the secondary) to get to the one that needs cleaning.

So, your order of dismantling is;
1. disconnect MAF and remove air filter box, 1 x hose clip & 2 x 10mm bolts
2. remove inlet duct, 2 x hose clips
3. remove secondary throttle body, 2 x 5mm allen bolts
4. clean primary throttle and butterfly
5. reassemble.

Now all i need to do is figure out the purpose of the secondary throttle body, anyone know?

 

[madleemark]

I thought one of the TBS had something to do with the traction control, please correct me if I am wrong

 

[smiffy]

@madleemark you are dead right, thanks for the pointer. I'd always assumed that traction control was done by changing engine management parameters such as ignition timing and fueling, or through the ABS applying an amount of braking to slow the spinning wheel, not by "choking" the poor old engine into submission!

Traction control on later fly-by-wire throttle engines, just have the one throttle body which closes if the traction control detects wheel spin.

 

[Dino D]

I had a spark plug coming loose that caused this.
Cheap enough to swap them all out of you use regular NGK ones rather than the expensive Iridium stuff (had both can't tell the difference!)