EGR Blockoff and CEL?
 

Will using a EGR blockoff plate cause a CEL?

can someone link me or explain what the ECM looks for from the EGR system?
edit, 2003
thanks.

at least on the NA's (96) it will cause a CEL. The ECU looks for a change in manifold pressure when the valve is open vs closed. This is why when I go to pass emissions I just vent the EGR to atmosphere on the intake side and leave the exhaust side plugged

does your EGR system no longer exist and is no longer connected to the exhaust manifold?

keep it. run it. it's not bad.

new turbo manifod does not have EGR bung. i can get the fitting from begi and have someone weld it on but was trying to avoid it. im chasing a couple of faults at the moment. EGR not ready, EVAP not ready and Secondary O2 heater circuit not ready. NO cel, but need to pass OBD2 emissions...

"Not Ready" does not mean "fault". Evap monitors are notorious for taking forever to run, and only under very specific and usually annoying conditions. Just drive the car. A lot.

If you removed EGR, expect the EGR monitor to fail. Then you will have a CEL.

I'm not sure if Mazda does this but I know some cars will open EGR and look for a change in o2 signal and MAP at the same time, so any little change to the system might trigger the light.

yeah, i know all that.... it has not reset in almost two years... im trying to avoid throwing parts at it.

I know some cars do that, but I need to know what the Miata does and what I have searched does not explain it. i have read that it has passages in the IM that it looks at and all kinds of other goofy stuff...

EGR needs to be ready before other readiness tests will clear. I made that mistake a few years back. I vented my EGR to atmosphere and all my ready tests cleared within a few miles.