vVind

Hey

The idle on miata is about 1000rpm but when i give it gas and on the down motion of the rpm needle, it likes to sink to 400rpm and sometimes even stalling on me. Anyone know what could this be? Tuning on the megasquirt? The throttle body?


Thanks

lordrigamus

iTrader: (14)

Is your closed loop idle control on. If it is, you may have to adjust the settings. You may also have to tweak the idle screw on the throttle body to get it to idle at the rpm you want.

Another trick is to slightly enrichen the cells in which your idle rebounds after a decel. This aids in the idle recovery. Post your msq.

Rushin

iTrader: (3)

yeah post you map. I had a horrible idle drop on my car. But i am pretty sure that was caused by a leaky headgasket.

vVind

Hey
I dont have access to a laptop that can get the map to you guys right now..
So do you guys think it is because my throttle body is bad?
I am going to get the throttle body replaced tomorow to see if it will fix the idle issues

Rushin

iTrader: (3)

i doubt its your throttle body. Why would you even think its your throttle body?

vVind

one of my mechanics was saying its the throttle body going bad..
do you think they are wrong?

leaky headgasket? how much would it cost to get this fixed
ill check it out with another mechanic tomorrow

ssmith

iTrader: (10)

Just tune it out with megasquirt, free is always good.

Braineack

iTrader: (62)

needs more enrichments.

Rushin

iTrader: (3)

Headgasket is expensive if you have someone else do it. U need to get the head machined. I have already done it twice and to me it's not too hard but if you are not very mechanicly inclined it is a lot of work. At the shop it will coat you probably somewhere around 500 bucks.

gospeed81

iTrader: (51)

Any monkey can change parts...a true mechanic makes a diagnosis.

I seriously doubt your throttle body is going bad...stop taking your car to those monkeys.

Another option is to do the BMW VTPS (variable throttle position sensor) mod...which allowed me to get rid of my idle droop (and dying).

https://www.miataturbo.net/forum/t12239/#post157397

I picked mine up cheaply...and was a cinch to install and calibrate.

Besides this there is just managing the enrichments of those cells.

Also, when you run datalogs MLV will change those values around on you, so write down a little table of the values you get to work so you can change them back.