supercharged idle problems

[ady_GTi]

Running a JRSC on a 1.6, having problems with the car almost stalling when the revs drop from a significant rpm.

It seems to only affect it when its warm and ive noticed today that its worse with all the electrics on.

Checked the alternator and its putting out 14V with nothing turned on and 12.5V with everything turned up.

Is there anything i can do or check? Or is this just a typical "supercharger idle droop" Im running powercard fueling at the moment but will be getting a megasquirt shortly and if its mechanical i would like to sort it before i start mapping!

Cheers all!

[CaptainSlow]

Does it happen when the car pulls up at a stop? If so could be just an adjustment to the manual idle control.

[MX-5 Lazza]

That does sound like SC idle droop but it needn't be that bad if you don't have an intercooler.
As CS says, adjust the base idle and it will probably be 90% sorted

[ady_GTi]

Not intercooled at the moment. i have messed with the idle screw, if anything its higher than the ecu idle. ive almost run out of adjustment to get it down to where it should be!

[anonymous-user]

I don't know how supercharged engines differ but would resetting the base idle help?

http://www.miata.net/garage/ignition.html#timing

Edited by anonymous-user on Tuesday 2nd November 20:15

[MrFlibbles]

I had this problem when i fitted big injectors to my turbo set up. I adjusted the throttle cable so the throttle stayed ever so slightly open at idle. It hasn't stalled since. (But does idle around 1200)

[MX-5 Lazza]

ady_GTi said:

Not intercooled at the moment. i have messed with the idle screw, if anything its higher than the ecu idle. ive almost run out of adjustment to get it down to where it should be!

Something is wrong then. Idle adjustment should be no different from stock. Have you checked for a vacuum leak?

[ady_GTi]

Not checked very thoroughly to be honest. Im thinking the ICV hose is the most likey culprit? Had the throttle apart recently perhaps it needs sealing up better.

Will give things a spray over with carb cleaner and see if it effects the idle.

[NeoVR]

Does the JRSC have the second throttle-plate before the 'charger?

[MX-5 Lazza]

NeoVR said:

Does the JRSC have the second throttle-plate before the 'charger?

There is always a throttle before the supercharger. The 2nd throttle in the stock position is optional

[ady_GTi]

Yeah im running the STD set up ie TB before the supercharger. As said running two is optional.

Had a spray around some of the joints and didnt notice any idle changes, dont think its a leak :-(

Thanks for the ideas and tips so far.

[MX-5 Lazza]

Have you checked base idle using TEN & Gnd in the diagnostics box?

[ady_GTi]

Well, kind of an update.. I rerouted the idle control pipe thing that runs from the original throttle body location to the supercharger, now its not sat right behind the radiator, made sure it was all tight as well. Has stopped the problem but im not sure if its just the lower ambient temps (was always worse when hot) Seems promising though! yay!

I have messed with the base idle loads by the way, first thing i tried!