I decided to remove my EGR valve today, to see if it needed cleaning. While removing some accumulated carbon on the pintle, I started to wonder if the EGR valve was still operational. Since I do not have the luxury of a vacuum pump, I decided to press onto the under side of the valve diaphragm, thus raising the pintle into the EGR valve.

My question is, if I put my finger over the vacuum port/nipple, should the pintle hold it’s current position if I remove my other hand from underneath the valve diaphragm?

Mine does not hold it’s current position, the pintle moves back to it’s original position. Does this mean the EGR valve is bad?

I hope I made myself clear. Thanks in advance.

P.S. This is for an 88 Duke

No, you can't test it like that. The air simply expands. You can hook a hose to it and suck with your mouth and activate it. I did this on a V6 car the other day and the car died almost immeditely.

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You can test the 2.8L engine EGR using natures vacuum pump; if you suck on it or it doesn't hold vacuum then it is bad. HOWEVER, the 2.5L EGR cannot be tested using a vacuum pump - it works using a combination of vacuum and exhaust back pressure.

Thanks for the fast response

I already tried the mouth method to no avail.

I just realized that I could probably test the valve by reinstalling it. There is enough room under the diaphragm to feel for vertical movement. The air filter assembly would have to be removed for easy access. Before starting the motor I can reference the location of the diaphragm, this should be the closed position. The diaphragm should be in the same location with the motor started, while idling. Using the throttle cable, I can then rev the motor up just a tad and hold it constant. This should mimic a cruising condition although no real load is placed on the motor; hopefully the diaphragm will move, thus opening the valve. I can also blip the throttle for fraction of a second to mimic WOT and feel if the diaphragm moves, thus closing the valve.

I guess this should be done rather quickly, before the valve has a chance to heat up
Ouch!!!

Does this sound feasible? Regardless, I need to put the EGR valve back on anyway so I guess I can try it like so. Sorry about my rambling

[This message has been edited by Phantom Rage (edited 06-28-2002).]

The egr will not work until the engine is warm. It should move as you rapidly accelerate then return to its current position.

Phil

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GTDude
25 years GM experience