1984 EGR Valve Question

[Thomas F.]

I need a little help with a technical question concerning my 1984 Corvette. It is my understanding (correct me if I am wrong) that for this valve to function as GM intended, it requires a certain amount of exhaust back pressure. Assuming this is true did I make a mistake when I replaced my cat. and mufflers with more free flowing designs?

[Joe L.]

Re: 1984 EGR Valve Question

I need a little help with a technical question concerning my 1984 Corvette. It is my understanding (correct me if I am wrong) that for this valve to function as GM intended, it requires a certain amount of exhaust back pressure. Assuming this is true did I make a mistake when I replaced my cat. and mufflers with more free flowing designs?

Thomas------


I'm quite confident that a change in the exhaust won't affect EGR system operation.

However, a change in the exhaust configuration, especially if the catalytic converter was eliminated, will definitely cause other engine problems.

[Edward J.]

Re: 1984 EGR Valve Question

I need a little help with a technical question concerning my 1984 Corvette. It is my understanding (correct me if I am wrong) that for this valve to function as GM intended, it requires a certain amount of exhaust back pressure. Assuming this is true did I make a mistake when I replaced my cat. and mufflers with more free flowing designs?

Tom, Some EGR valves do work with some back pressure along with vacuum, I would think the GM service manual should help spell it out. I cannot recall if 84 did. I would not think a free flowing cat. would have any effect though.GM went through a lot of driveability issues with those dam valves so it helped some cars and not others with back pressure.

[Page C.]

Re: 1984 EGR Valve Question

Not sure about 1984's but as you move into the later 1980's early 1990's the EGR valves have a "N" (negative pressure) or a "P" (positive pressure) stamped in the the EGR valve cover after the part number. Like Ed said they can be a nightmare.