Testing a Vacuum EGR System

[sattech]

How to check a vacuum operated EGR system
On a '91-'94(non Ca) Saturn uses a vac operated EGR valve.
To check the valve you will need a vacum pump.
test1
With the engine off apply vacuum to the valve. The valve should move to the open position and hold vac. Release vacuum. The valve should slowly drop back to the closed position.
Test 2.
Apply vacuum and hold. Start engine. The valve should vent the vacuum and drop vack to the normally closed position when the engine starts.

Test 3
With the engine running. reach under the valve and pull up on diafragm-CAUTION VERY HOT-.
engine should stumble, possibly stall.

If test 1or 2 fails the EGR valve is bad. If test 3 fails, the EGR passage is plugged.

A code 32 can only be set by an EGR valve that doesn't move( no vacuum or hole in diafragm) or a plugged passage.

If you have a code 32 and all the above tests pass, then the most likely cause is a bad solenoid or loss of vacuum.

[savage]

i thought that you had to test it w/ a scan tool to make shure that the electrical part of the sys was working

[freakerz]

i changed my solenoid.. didnt fix code 32.. guess its the valve.. and i carb cleaned it.. whats the price of a valve??

[GmG]

Originally posted by savage
i thought that you had to test it w/ a scan tool to make shure that the electrical part of the sys was working

Are you sure you aren't thinking of the electrically operated EGR valve? From what I understand, the PCM doesn't have any way of knowing how far the valve is open on the vacuum operated valve. The valve itself doesn't have an electrical connection, just the solenoid.

Originally posted by freakerz
god damn, changed my solenoid.. didnt fix code 32.. guess its the valve.. and i carb cleaned it.. whats the price of a valve??

I just paid about US$65 plus shipping from saturnparts.com for mine. Don't forget to buy a gasket! :grnjump:

George

[David 93 SL2m]

Originally posted by GmG
I just paid about US$65 plus shipping from saturnparts.com for mine. Don't forget to buy a gasket!When I bought a new Saturn OEM EGR valve for my 1993 SL2 a while back, it came with a new gasket. I need to look for the receipt to see the part number and the price I paid.

[gdelgrego]

In addition to the tests in the original post, there is one additional to check for a plugged vacuum bleed:

- With car running, apply vacuum from a hand pump to the EGR valve. If the EGR holds vacuum and opens (causing the car to want to stall), the vacuum bleed in the EGR is probably plugged.

A valve can pass all the FSM tests but still cause low speed surging if the vacuum bleed isn't clear.