I have a 91 Crx HF with D15b6. I was wondering if it is normal for the engine not to stall if I apply vacuum to the EGR while the engine is running? I cleaned the EGR very thoroughly and reinstalled it. But it just doesn't seem to stall if I apply vacuum to it while the engine is running. No engine hestitation or cause the rpm to drop. Is this normal or do I have a clogged intake manifold? Yes the engine was fully warmed up before the test.

 

the engine should stall at idle when vacuum is applied to the diaphragm and the EGR opens. either the egr isn't opening (does it hold vacuum? have you tested it off the car and verified it's opening?) or the ports are plugged, either on the exhaust side or the intake side.

 

I have took it out of the vehicle and cleaned it. It wasn't as dirty as I had expected, but I cleaned it and tested it with a manual hand vacuum. It is holding vacuum with no leaks. How should I proceed with cleaning the Intake Manifold?

 

Could be possible that there's a leak between the manifold and head too (?), may be good to just pull it off and replace the gasket, clean up the IM with some carb cleaner and rags, then torque it all back down to spec.

I'm not really sure though what the best way to clean the IM is, it may depend on just how bad it is. I've seen some people go as far as using a blowtorch to blow all the carbon out of the runners/plenum.