EGR ??'s

[Fakeyankee]

My engine seems to be running kind of rough at idle and I was looking for a vac leak since some of the hoses look old and need replaced......anyway, I unplugged the vac line to the EGR and there was vacume in the line but the EGR valve appears to be stuck. Could this cause a rough idle ?? All else appears to be normal. Thanks !!
Darrell.

 

[gofstbuick]

How much vacuum and on which line. The source vacuum to the solenoid is manifold vacuum, there is a vent (on the solenoid with a cover over a filter covering the vent port) and the other port is the port that applies vacuum to the EGR valve. There should be manifold vacuum to one port of the solenoid and no vacuum to the line leading up to the EGR valve. If the filter gets plugged, it could cause the egr line to see vacuum.
What do you mean by the EGR is stuck? Have you tried pushing on the EGR pintle and the EGR does not move? If so, is it stuck open or closed? If open, it will cause rough idle and if closed, it will idle normally. You can blow propane at the EGR valve and watch the block learn number, or O2 numbers to see if it looks rich. That can also tell you if the EGR valve is leaking past the pintle.

 

[Fakeyankee]

Thanks for the reply gofstbuick.
The EGR valve is stuck in the " up " position. You say there should be no vacum in the line to the EGR ?? Can I clean this filter on the solenoid ?? What should I do next to fix this problem ? Thanks again !!
Darrell.

 

[gofstbuick]

The EGR filter is still available from GM and so is the EGR (if it is frozen solid in the up position). If you need a new EGR valve, I would strongly suggest using a factory unit. Especially if your vehicle is subjected to dyno type emissions test. The aftermarkets do not flow to the spec of a factory unit (especially the type that uses washers to set flow requirements and the ones with an auxillary back-pressure transducer).