9TransAM4

hey guys well i just got the tranny rebuilt, and wouldnt you know its one thing after another. my ses light has been comming on and off, and i got it scanned. it says my egr valve is not functioning correctly. now i know this ising a huge deal, but i noticed that it is behind the engine, and very hard to get to. what kind of fix is this, and how in the hell do i get to it? its a 94 Trans am

Injuneer

What was the code? There is one for the valve (32) and one for the solenoid (27).

9TransAM4

its the valve

Injuneer

DTC 32 is fairly rare for the OBD-I cars.... many people completely remove the EGR valve and never get the code. I would remove the valve and clean it. While its off, put a vacuum on the vacuum connection to see if the pintle moves like it is supposed to.

It may look like its hard to get at, but there are just two studs in the back of the intake manifold, and two nuts that need to be removed to remove the valve. You can reach around and work "blind".

Unfortunately, in this photo the vacuum line has fallen off the fuel pressure regulator and is blocking the view of one of the nuts.

Back of intake

kevmor99

What does the valve do anyway? And also what are the two boxes and each side of the intake for? I think the passenger's is for the evap. canister, I don't have one so I just hooked the line that went to the canister to the intake, but I might take them all off.

Injuneer

When combustion chamber temperatures start to increase, the formation of oxides of nitrogen (NOx), a pollutant, will increase. By allowing a small amount of exhaust gas to enter the intake manifold, and then the cylinders, the combustion chamber temperatures are lowered. That reduces the polutant NOx, and also will help reduce the possibility of detonation when you are lugging the engine in the wrong gear, or pulling up a hill in a fully loaded car.

The "boxes" on either side of the intake manifold are "solenoids". The one on the drivers side pulses, to control the vacuum to the EGR valve. It is vacuum that opens the valve. You can delete the system, but it has no negative effect on performance - as long as the valve isn't leaking - since EGR never operates at WOT. In an OBD-I setup, you will probably not get a code/SES light for deleting EGR. In an OBD-II car (96/97) you are almost certain to get the code/SES light. It can be "programmed oput" of the PCM.

The solenoid on the passenger side is the EEC (evaportative emissions canister) purge solenoid. Under certain conditions the solenoids opens to allow the fuel vapor collected in the charcoal canister in the drivers rear fender to be pulled into the engine and burned. It doesn't affect performance, and helps keep the smell of fuel away from your tank and fill pipe.

Again, deleting EEC will set a code in OBD-I only if you disconnect the wire from the solenoid. But in OBD-II, there is a detector to make sure there is flow in the system when there is supposed to be, so = code/SES unless you have it programmed out.

White96Z

I had this problem with mine a few years ago, and it was indeed the valve itself. Turns out it was covered under a TSB by GM for 95-96 f-bodies. Unfortunately I had already fixed it out of pocket...no big deal though since a new valve is only 45-50 bucks. The valve is actually quite easy to get to. Just use an open ended wrench and a little hand mirror if you want. You shouldn't have any problems at all.