Can't figure out why my idle is so dang high! (new S/C)

[deathtrapmiata]

1994 mazda miata. 99 engine, header/custom exhaust, NO MAF, Just added a Jackson racing M45 small boost charger (6psi)
MS PNP (Gen 1), Highflow FP, 425cc injectors.

My idle is like 1700rpms, and i cant get it to go down. also when i crank up my engine. it revs furiously to 4k rpms! then twiddles back down...

I Had an almost perfect idle before i put the s/c on, with these settings, but just slightly tweaked

[Matt Cramer]

Can you also post a data log?

[deathtrapmiata]

Can you also post a data log?

Yes here is one short one i did earlier to see my max boost, (3.5 psi), which is another issue I am dealing with at the moment.
The consensus is that my supercharger belt is not tightened enough, there are no intake leaks, as a matter of a fact i am about to go check right now again for tension

[nathanhardy]

hey not sure if this would have anything to do with it but your map decell is always on. youre running ms1 right? im not sure about this thought but could the sc be forcing the throttle plate open at idle. id try adjusting only after you double check things but id also think something like idle would for sure need be adjusted after a sc install, maybe even timing

[deathtrapmiata]

hey not sure if this would have anything to do with it but your map decell is always on. youre running ms1 right? im not sure about this thought but could the sc be forcing the throttle plate open at idle. id try adjusting only after you double check things but id also think something like idle would for sure need be adjusted after a sc install, maybe even timing

Can you explain a little more? Im not seeing a setting for MAP decell.
were is that in Tunerstudio?
also yes i am running ms1

[nathanhardy]

so when I view your log in mlv it shows on the far right bottom a indicator call mapdecel and its always lit up. at 4060.359 on your log you're also getting a tps decell trigger but from your msq you shouldn't have any deccel fuel cut at all.. im much more use to ms2 since I upgraded have you ever thought to upgrade it was pretty easy to do and I didn't have to change anything on the main harness it was all done in the case. my car runs much better and the 16x16 would give you an edge now with the sc. but back to basics my thoughts are much like yours why would a sc change the idle.. have you double checked vac lines and any thing else that can let air into the motor?

[Matt Cramer]

The MAP DE indicator doesn't work for MS1 based systems, only MS2 and later.

I would try less timing at 1200 RPM and adjusting the idle speed set screw.