EGR - what would happen if it was blocked?

You might be able to block off the EGR, but If you remove the EGR value, it will trigger a CEL because there is a feedback circuit in it.

I have a theory that EGR is greatly increased during lean-burn. Exhaust contains very little free O2 and free O2 after combustion is the cause of NOX formation. The unusual location of the EGR injection points also leads me to guess that EGR may also be the cause of stratification in the combustion chambers. I.E. An easy to ignite stoich mixture next to the spark plug and a lean mixture elsewhere.

So, if you have a 5spd, when you go into lean burn and the extra EGR isn't there, the ECM may not like the O2 sensor readings and may toss another CEL.

Oh, one more thing. People recommend that I remove and block off the EGR on my toy (a 93 RX7) not for more HP, but because they often fail and leak.

Blocking it would be very simple. Just cut a thin piece of metal the same shape as the gasket just without the holes. Then reinstall.

If you Block off the EGR you could blow the engine due tp excessive pressure or is that the PCV valve. Either way I would just leave it alone. damn im tired and cant think straight

Your thinking about the PCV valve. Positive Crankcase ventaltion valve

The EGR valve simply take the dirty hot exhaust gas and places in into the cool clean intake air... Good for emission. Good for MPG. Poor design on almost any engine that causes the intake to become clogged with carbon/sut



I plan on blocking the EGR once I get my OBDII software. Just to see what happens :?

Oh, one more thing. People recommend that I remove and block off the EGR on my toy (a 93 RX7) not for more HP, but because they often fail and leak.

Click to expand...

Here's the thing about that: they don't know what they're talking about. A leaking EGR on a rotary will be no different then a functioning EGR. In fact, all the 89+ engines completely eliminated the EGR since Mazda decided it was not necessary due to the "natural" EGR ability of the rotary. If they added one in '93, then this is news to me. But then I don't work on 3rd gens as a rule.

I blocked off the EGR valve using a piece off of a coke can. Blocked it off real nice. I took a 5 mile trip down the road turned around and about 2 more miles the check engine light came on. Not sure if it was realted or if it was because the car warmed up but the surging was still present.

CEL was for insuffecent (sp) flow on the EGR