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I have a 1990 GW w/a 360. The PO installed Elderbrock intake and Holley carb. Also installed Mallory ignition. I have an exhaust leak at the manifold. I am going to remove both exhaust manifolds to repair. In the process, I want to delete all the smog stuff. I'm looking for some "heads up's" on things to watch out for. Do I need the EGR?
Also, I have oil pooling on my intake, and also settling in the air cleaner. Possible causes?
Well, don't delete all of the smog stuff. There are a few things that are very effective and have zero impact on performance.
The PCV system. This draws air from the crankcase and burns it. Really does a fantastic job of reducing hydrocarbons. Also will keep your engine and jeep from smelling like fuel and gas. (This was the very first mandated emissions equipment and, again, it is probably THE most effective and does not impact performance)
The EGR. Exhaust Gas Recirculation. Replaces air with already a bit of exhaust. When properly connected it will not impact performance, it turns off under full throttle.
The charcoal canister. This captures fumes from the tank and the carb while the engine is stopped and will allow the engine to draw these in when you start the car. No performance impact from this system. Try to keep it. It will help avoid the 'gas smell' when the car is sitting, especially if it is in an enclosed space.
Don't ditch the catalytic converter, it is very effective at cleaning the exhaust. If yours is old, get a modern one. They flow much better and also do a better job of cleaning the exhaust.
The A.I.R. system. This is probably the biggest part of what you are referring to. This is the overly complicated system that includes the pump on the front of the engine, a few major hoses that cross back and forth across the engine a diverter valve and air port to the exhaust. If you remove all of this you will want to plug the holes left behind in the exhaust manifold. Lot's of write ups on how to do this. If I didn't have to have this for emissions (visual inspection), I would get rid of this system. It's complicated and mine doesn't work anyways. I pass emissions because I have my engine well tuned and a later model catalytic converter.
A lot of the other emissions systems on your jeep are an old school attempt at modifying the spark advanced based on engine temperature. It's all vacuum driven but it also integrated into the overall system. So make sure you know what you are disconnecting before you start.
There is also a system that diverts the air that flow into the air cleaner on startup so that it passes over the exhaust manifold first. This allows the engine to run a bit better on a cold start and also get to operating temperature faster. The sooner you are at operating temperature, the more efficient the fuel burn and the cleaner the exhaust (as a general rule).
Last edited by will e on Sun Sep 15, 2019 4:57 am, edited 1 time in total.