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View Full Version : PCV plate/EGR valve help



Boone.Msi
02-07-2007, 02:32 PM
They're pretty much the same thing right? As most of you know, i have had an idle issue for months now, i replaced all needed gaskets, plugs, o2 sensors, maf sensor and the PCV plate

yet i still have a horrible idle, i have gone to get my emmisons tested twice now. They both failed horribly in the nox portion.

acording to this definition of an egr valve, it seems like the PCV plate is the culprit. So if i bought a new one, with a new gasket, why am i still having this problem...help.



The EGR valve is the main emissions control component in the exhaust gas recirculation system. The valve is located on the intake manifold, and opens a small passageway between the exhaust and intake manifold to allow a metered amount of exhaust to flow back into the engine. This reduces combustion temperatures and helps control the formation of oxides of nitrogen. The EGR valve is opened by the application of vacuum to its control diaphragm. Some also require a certain amount of exhaust back pressure before they'll open. On newer vehicles, the valve is electronic and uses one or more solenoids or a small stepper motor. The valve should remain closed while the engine is cold and at idle. It should only open once the engine has warmed up and is running at part-throttle. If the valve sticks shut (or is disconnected), NOX emissions will soar and detonation will often result (See Detonation and Spark Knock). If it sticks in the open position or fails to close all the way, it acts like a vacuum leak resulting in a rough idle, hesitation and possible stalling.

There are 3 nipples in my pcv plate, 2 of them are connected to brand new vaccum tubes and the 3rd one is capped off with a shitty cracked cap(exactly the way it was) would this cracked cap be the reason for this?

winfred
02-07-2007, 11:07 PM
the pcv plate is nothing like a egr valve, that engine does not have egr the closest thing to it that it does have is air injection, a electric pump blows air into the exhaust manifolds during cold start and it's managed by a solenoid and diaphragm, all the pcv plate does is manage pressure in the crank case (and it doesn't do a great job of that)

BillionPa
02-08-2007, 01:13 AM
did you replace... the charcoal canister?

632 Regal
02-08-2007, 11:00 AM
Nikasil? *shrugs*

Does it seem to have a miss at idle in gear? Replace the nipple plug, doubt that has much to do with it tho.

While idling check that it has vacume at the crank case by removing the oil cap or dipstick, you should notice a change at idle.

If you do have a miss at idle, replace the plug boots, if that dont do it you might have a few weak coils.

did you check the intake tube for cracks? all clamps tight? ICV clean and move freely?

winfred
02-08-2007, 12:19 PM
after a cold start spray around and under the intake with carb cleaner, if the idle changes you have a leak