High Idle with M45 and MS2 - Help Needed
 

Yesterday, I got my car, a 1.6 with Megasquirt PNP 2 and an M45 kit running and driving. I'm still tuning it and getting things dialed, but I am having issues getting the idle down to a reasonable level. I am unable to get below 1300 RPMs at idle, even warm. This is with the idle adjust screw all the way in and trying what I can on MS. Some luck was had greatly retarding timing in the low RPMs, but not sure that is the best idea and I was still not able to get below 1300.

I know a good idle can be had with Megasquirt and I am not interested in doing dual throttle bodies (which I know is not really pushed here, but I asked the same question at Miata.net and that seems to come up a lot), but I am hoping someone can help me figure out how to to this.

FWIW, I am running RX8 420cc injectors and deleted the AFM as well. Non-intercooled (for now).

Idle was set using PWM warmup, we adjusted the idle screw and the idle valve duty until the lowest RPM was achieved. Oddly lower DC than 30 resulted in a higher rpm, and same with DC higher than 30. We did set the trigger angle with a timing gun and verified that timing is correct,

diypnp?
mspnp2?
custom built v3.0 pcb w/ms2 daughterboard and custom pnp harness?

what you do have?

Sorry, left out the most important part, I suppose. It's an MSPNP 2. Hardware is 1.2 if that matters. I updated the OP as well.

fix your vacuum leak then.

Alright, that is what I was leaning towards and I am now thinking the tee fitting to my MAP sensor may be the issue. Hoping that sorts it out.

Problem mostly solved I think. I checked all the hose clamps with no luck, but I ended up capping the idle balance line. It was routed to the L shaped fitting towards the firewall and basically just dumping air behind the TB. I see on a stock JRSC set up, that should be routed from pre-AFM to behing the TB, giving it some resistance. Since I deleted that going Megasquirt and have full control of the IAC valve now, no need for it. So, I capped it and went from 1500 RPM idle to 1000 RPMs. Some final tweaking and I think I can get it down to 8-900 like it should be (laptop battery died before I could really fiddle with it)

https://www.miataturbo.net/attachmen...ine=1429723315