I was messing around under the hood today and noticed something funny.
On my EGR solenoid ( tpi ) there are 2 vac lines running from the EGR, but there are no vac lines running off the other side of the solenoid.
Does someone know how this is suppose to be hooked up?
No wonder the car won't idle right.
Thanks.

 

I can only make reference to my EGR but the way it works on mine is that I have a vac line from the throttle body to the solenoid then from the solenoid to the egr. I'll take a quick look tomorrow and try to get some pics too if you need.

The only thing is, the EGR is NOT supposed to be called when the engine is at idle. Basically there shouldn't be enough vacuum at idle to activate the EGR. At high rpm the egr is also not commanded as the solenoid will only function up to a certain RPM range then when vacuum is too high it also does not command the egr function as it isn't necessary. So basically the rpm's its commanded at ranges from 1500 to 2500 rpm.

Check to see that the egr is closed at idle basically, unplug the egr's tubing and that should keep it closed. If you have vacuum from the tubes then the egr is being commanded open and you will not have a proper idle since you are having exhaust gas recirculate when its unnecessary.

 

On my EGR valve, there are 2 vac lines. I'm guessing, 1 from below the diaphram and 1 from above for bleeding vacuum or the other way around. ( like I said I'm guessing ) But if this is the case, there needs to be a vac line on the solenoid to feed the EGR, right?
If this is correct, my EGR has never worked since I've had the car, cause there has never been a vac line to the solenoid.
BTW, you're right. Guess I'll keep looking for that rough idle solution.
Thanks.

 

From what I know of the egr its a pretty simple design.

A vacuum line from the solenoid opens the diaphragm which allows exhaust gas to recirculate back into the intake manifold. Under idle there is no EGR function, takes a good amount of vacuum to open it. At high rpm, the ecm commands the solenoid shut so no egr function there either.

Even if the EGR doesn't get a vacuum, it can still be seized in the open position allowing exhaust gasses back in making for a rough idle. Try blocking off the EGR and see if the idle stabilizes. The diaphragm should be in the lowered closed position. If the springs are broken or its jammed, it may stick open. Make sure the diaphragm moves freely simply by pushing on it from the underside.

Things that can force an EGR open:
high exhaust backpressure (clogged cat will do it)
weak spring mechanism in the diaphragm
vacuum to the egr when not commanded

It's quick drawing time...

 

Thanks Slade, I'll check it out.
The EGR valve is less then 3 months old, so if there's a problem with the valve itself, it may be warrantied still.
Either way, I need to find out what happened to the vac line that goes to the solenoid. If the valve is closed, there is no way it can open without vacuum.
I keep you posted.
Thanks again.