Boost is unstable at peak when wastegate opens
 

Hey guys.

I have a 1992 miata with a FM2 kit on it.

Same old garret 2560r. Im running a megasquirt ms3 build by rev. Im also using a manual turbosmart boost controller.

My problem is, the car pulls and drives really well until you hit the wastegate pressure. Then the car bounces around almost like its hitting a fuel cut rev limiter.

I can see in the graphs that the boost is really unstable when the wastegate is opening.

This can happen at a variety of rpm's and if I dont hit peak boost to open the wastegate everything is smooth and fine. My boost controller is set to 12psi.

Any ideas? Ive attached a log in which this happens often and here are some photos of the issue aswell.

Thanks!
https://www.miataturbo.net/attachmen...ine=1447641091


https://www.miataturbo.net/attachmen...ine=1447641091


https://www.miataturbo.net/attachmen...ine=1447641091

Figured out it was spark blowout (was unfamiliar with this).

Needed to gap the plugs down a bit more.

Thanks for following up with the solution, I hate searching and pulling up old unresolved threads.

Sometimes new plugs will help if yours have been in there a while. If you keep having issues the Toyota COP thread is great for walking you through building a relatively inexpensive coil on plug conversion.

Ya, me too, thats why I came back and posted what I found.
Obligatory XKCD https://xkcd.com/979/

I got some nice new plugs and wires, gaped em down, and have no issues now.

COP's are on my list of things to eventually do to the car.

Thanks!