mack123

iTrader: (4)

hey all,

In wondering why the egr solenoid on the turbo{n/a also?} is always normally closed,and yet with the ignition on, a normal reading at the computer shows youve got 12v opening the solenoid, { pin 2n} thusly opening the egr valve solenoid, and the vac actuated valve

why would you want to have egr at idle or every time you have even the slightest vac going on ?

I thought it only worked at highway speed

maybe its something I need to get rid of,anyone agree?

hugues

http://www.geocities.com/huguesdc1/egr.html

12 V means that the solenoid is NOT energized (ECU pins get grounded to activate a solenoid) ...

at idle, you really don't want EGR to be open !!! so, yes, you're right about when the EGR should be open.

Some inspection stations do a visual on the EGR and some even do the 'apply vacuum at idle and see if engine stalls' ... depends on your state and the station.

Hugues -

mack123

iTrader: (4)

thanks hugues, I checked out the link and it was helpful.
Yet I think its backwards...
The fsm explains that the egr solenoid is normally open, meaning when you remove it and blow thru the ports,it will take air from the vac source to the egr component

and it explains when you appy 12v, the valve closes and air,vac exits out that little air filter in back.

I guess the turbo solenoid acts the same, and the other 3 solenoids work the opposite, meaning they are always closed at rest.

I removed mine recently and did all these tests, and they matched the fsm.

so Im wondering why if theres NOT a ground at idle or ignition, {meaning the valve is open from component to vac source}

or would the 12v at pin 2n be grounded, the fsm says its an output 12v. This 12v would activate the egr and keep it closed, meaning no egr.

The reason i say all this is my idle really sucks and Im thinking the egr is to blame.

I guaess if I disconected the 12 conector the egrwould be always shut

mack123

iTrader: (4)

typo error, i meant the other 3 solenoids, pressure,switching and relief are always open at rest, accepting vac from supply to component until `12v shuts it this is on the turbo

hugues

FSM is correct ... you should have 12V at idle on the egr solenoid.

To check ECU Signal and proper operation of egr solenoid at idle:
- there should be no vacuum coming from the line that goes to the EGR

To check EGR valve itself at idle:
- apply vacuum with a mityvac pump to the EGR valve
- the egr valve should maintain the vacuum and the engine should stall or runs very rough (because egr valve is then open)

If nothing happens when you do the test, the diaphragm is busted but the EGR is probably stuck closed ... it could be stuck partially open though (I don't think you can tell unless you take it out).

Hugues -