After reading everything about the egr passage getting clogged and causing hell with the Old's 307's, I pulled my carb. To my amazement the passage was clean. The bottom of the carb however was very dirty. I wish I would have took a before pic of the carb, but I got a little gun hoe on the crud. :blast: Take a look at the pic's below. Wich is the actual egr passage on the carb. The area in the blue circle is what was really dirty with crud. Would just that be causing my pinging problem. I know my next step is a basic tune up and to put a timing light on it. But from what I've heard, I was just sure that was my problem. Thank's for any input. Cal egr valve passage
If your having problems with pinging in that engine its probably a bad egr valve. I had an 87 Safari wagon that I had to use premium in to keep it from pinging, and the gas milage sucked. I enden up replacing the egr valve and all was well! I went back to using Sunoco's 86 octane with no problems, and my mileage picked up about 2mpg. EGR is a good thing! Mark
The picture labeled "egr tube" is correct. Make sure they are clean. The picture labeled "egr passage" is correct. It goes from under the egr valve to under the manifold. It doesn't need to be "clean", but it shouldn't be blocked. I'd say if it appears to be more than about 25% plugged you might want to remove the manifold and open it up. The picture labeled "egr valve " is also correct. Check to make sure it works. Put your finger underneath until you locate the diaphram. Make sure it works up and down. Then start motor. With motor idling, push the diaphram with your finger, closing the valve and forcing the exhaust through the passage and into the intake. The engine should run a lot rougher and maybe stall. If there is not a significant change, then the egr valve is bad, or the passage/tubes are blocked. The picture labeled "circle" doesn't have anything to do with the egr system. There is a guy named "Chris" who has some good info on his website about the CCC system and electronic QJets used on 307s. Here is his webpage: http://performanceolds307.tripod.com/backup/index.html There also is some good info on 307 emissions and driveability issues in the Haynes manual for full-sized Buick Olds and Pontiac (1970-1990), the Haynes Rochester Carburetor Manual, and Doug Roe's book on Rochester Carburetors. Rod
