lumpy idle on em1

[turbo convert]

hi guys,

just wondering, i got a em1 and i just completed intake and exhaust and now i have noticed the car gets a lumpy idle(its a slight up and down) this only happens once car is warmed up! However the revs stay between 740rpm-75xrpm or there abouts in other words its not dropping a cylinder due to bad leads as would be effecting idle........... any ideas what prob could be i will change plugs when i do a 60,000km service with in the month but whilst it still runs very well iam happy:D
Any ideas appreciated?
thankyou

[EuroDude]

Since you have modded the intake and exhaust, you should reset the ECU so the engine can learn how to idle properly.


If that doesn't work, then..

Jumpy idle when the car is warmed usually indicates a dirty IACV. Give that a clean and see how that goes. Give the throttle body a clean as well since it can cause various idle problems.

If you have ever turned the idle screw, re-adjust the screw so the engine idles at its stock RPM

[turbo convert]

I have reset the ecu when i installed my RSM
throttle body is spotless, unbelievbly clean i was looking the other day
screw new turned, but there is no problem with the idle as i said it holds the 750rpm mark spot on just the sound it makes is a small up and down noise but is only notacable now after exhaust


Since you have modded the intake and exhaust, you should reset the ECU so the engine can learn how to idle properly.


If that doesn't work, then..

Jumpy idle when the car is warmed usually indicates a dirty IACV. Give that a clean and see how that goes. Give the throttle body a clean as well since it can cause various idle problems.

If you have ever turned the idle screw, re-adjust the screw so the engine idles at its stock RPM

[EuroDude]

I see, I thought u meant the revs were jumping from 740 to 750.

Its probably just the cooling fan kicking in and out. When the fan kicks in, it takes a bit of battery power and slightly affects the idle for a moment.

How often does the sound happen?

[turbo convert]

Nah, I checked - the fan wasn't running when the sound occurred - that was my original thought as well.

[EuroDude]

I cant think of anything else that could cause a noise like that while the RPM stays the same. The A/C maybe?

I would re-adjust the idle screw (follow the proper procedure) and see how that goes. Fiddling with the idle screw can cause strange things sometimes.

[Waggy]

I had this happening with my EM1 - changed the spark plugs (to iridiums) and it fixed the problem.

[turbo convert]

well i will be doing that soon i think

[BlitZ]

you didnt get Xforece ehaders did you? hehe

[turbo convert]

no the fluctuation isnt a problem 10rpm is great its the sound it makes sounds lumpy.... only sound iam going on thats what intregues me, revs are a-ok
no i got rsr headers not xforce

[EuroDude]

When was the last time the tappets were adjusted?

[turbo convert]

Dont know i only purchased the car 5 months ago
but there not that noisy!
i changed the spark plugs last night i will see what happens