Stop in for a cup of coffee
The vent in the middle of the main diaphram is normally open to atmosphere. So nothing moves even if there is vacuum from a constant pump in the upper chamber.
When there is exhaust pressure, the lower diaphram closes the vent. Maybe that double guarentees no EGR at idle. Seems redundent so must be another reason to have spent the extra money making it that way.
Next time I'll try putting a hose over the nose and then pressurizing it with shop air that way.
Another tip from earlier book was phisically push the egr diaphrams open while idling. if rpms go down, at least we know its blocking the EGR at idle like it should. I did this once when I first got the jeep. That was easier than trying to watch for movement.
Found it. Here's how it works.
The vent in the middle of the main diaphram is normally open to atmosphere. So nothing moves even if there is vacuum from a constant pump in the upper chamber.
When there is exhaust pressure, the lower diaphram closes the vent. Maybe that double guarentees no EGR at idle. Seems redundent so must be another reason to have spent the extra money making it that way.
Next time I'll try putting a hose over the nose and then pressurizing it with shop air that way.
Another tip from earlier book was phisically push the egr diaphrams open while idling. if rpms go down, at least we know its blocking the EGR at idle like it should. I did this once when I first got the jeep. That was easier than trying to watch for movement.