Egr

[mike from Boston]

Hi Folks,

Looking for info on cleaning EGR for 94 accord, found a link but it was dead - anyone have any info to pass on?

Car failed emissions with high Nox.

Thanks,
mike

[mpumas]

High NOX can be caused by four things: the EGR valve and associated vaccum, the EGR ports are clogged, high carbon build up in the cylinders increasing the compression and therefore combustion temp. and a bad cataylic converter. The first thing is to check the EGR valve. Disconnect the vaccum hose and connect a vaccum pump with a guage to the valve. Start the engine, then draw 8"/Hg vaccum on the valve-the engine should stall and the vaccum should hold. If the engine doesn't stall and you are not getting a check engine light, the EGR ports may be clogged. (The ECU tells the EGR valve to open. The EGR valve sends a signal to the ECU that it opened. If it doesn't get this signal, a check engine light illuminates) On the intake manifold, there is a bolt on service cover that goes to all the intake runners on the intake manifold. and is parallel to the head and just to the rear of it. It is held on with 5 bolts. (The exhaust gas goes from the EGR valve to each of the intake runners through this service cover.) Remove this cover, and inspect and clean all the ports that go to each runner. If all ports are ok, the problem may be a bad converter. The only fix ithere is replacement. Keep us advised of your fix.