Should EGR Vacuum Modulator hold steady vacuum applied to the bottom (exhaust) port? (2 Viewers)

[jatree]

I have a new one from Toyota. I am applying vacuum to the bottom port and it doesn't hold - it will slowwwly go down from ~15mmHg to 0 over about 30 seconds. The FSM tests are useless (blow into Q while blocking P/R and determine how freely air flows).

Can anyone confirm whether this is indeed faulty behavior? I don't know where the vacuum test came from since it is not in the FSM.

Thank you

 

[paulzak]

I found testing these things to be inconclusive. If you install it and it works, you're done and thankfully it's a 30 second fix.

 

[jatree]

Thanks for the response. Installing is a piece of cake but I've had two melt on me in the last 12 months so as I go through the whole system - EVAP, EGR, Exhaust - I just want to make sure any new ($$) parts I put in won't fail on me again. I agree that testing is inconclusive unfortunately.

 

[jatree]

Well now that the TB is mostly off I'm gonna clean it and replace small vacuum hoses, change VSV, button it all up and do some tests with the new Vacuum Modulator and see what happens.

I'm still interested to know whether holding vacuum is a conclusive test so if anyone has experience that would be great.