NC: Dipping/Fluctuating Idle

NC_Hammer · Postby **NC_Hammer** » Thu Sep 29, 2011 7:04 pm

Recently i've been experiencing a dipping or fluctuating idle on my NC (6sp manual, 06).

Mainly on cold start, sometimes after a bit of a drive whilst warm; after acceleration and a pull up to a stop will cause the idle to dip to the verge of stalling then return to normal after 2-4 dips/fluctuations/hunts (dipping not revving).

Does anyone here have an idea of what may be the cause?

I'm thinking along the lines of Purge Valve, Throttle Sensor maybe? My NC has done 80k, with the normal maintenance as required and only run on BP Ultimate/Redline fluids.

Appreciate your input guys.

marty085 · Postby **marty085** » Thu Sep 29, 2011 8:11 pm

MX5 Idle Dip: "Since 1989" :shock:

NC_Hammer · Postby **NC_Hammer** » Thu Sep 29, 2011 9:32 pm

yes i know, one thing it seems has never changed, confused wether or not it's a good thing or not :lol:

Postby **NitroDann** » Thu Sep 29, 2011 9:37 pm

Fit some massive bump sticks, then you wont notice the dip among the lope :mrgreen:

Dann

Sailor · Postby **Sailor** » Thu Sep 29, 2011 10:10 pm

Mines just started doing somethin similar now and then.
Sometimes goes rich and rough idle at startup which clears as it warms.
Also wants to stall first time I stop after startup then OK Thinking idle air stepper but will look further next week.

Hjt · Postby **Hjt** » Thu Sep 29, 2011 10:53 pm

I get it when i engage the clutch after a decent drive, and when the engines cold. both of my mx5s have had the issue. It is worse on my nb turbo, i feel worse for "badbong" as he gets it when in reverse and often stalls. It's hilarious, but annoying.

NC_Hammer · Postby **NC_Hammer** » Thu Sep 29, 2011 11:58 pm

Sailor wrote:Mines just started doing somethin similar now and then.
Sometimes goes rich and rough idle at startup which clears as it warms.
Also wants to stall first time I stop after startup then OK Thinking idle air stepper but will look further next week.

Pretty much my situation as well Sailor. It mainly happens in the first 5 minutes of the drive then it normal once full 'hot' and run in. I've heard of people in the US changing the Purge Valve - could be vacuum/emissions related?

Hmmmm.