RTH: EGR Vacuum Modulator Testing (1 Viewer)

[SupraTuRD]

Hi guys. I'm currently in the middle of testing my EGR Vacuum Modulator to see if it is good or bad.

Per the FSM, when air pressure is applied to port Q while ports R and P are covered, air should escape through the filter.

Mine does allow air to pass through the filter, but air also escapes out of the larger port on the bottom of the modulator.

Is the modulator faulty or is this normal behavior?

Thanks in advance!

 

[SupraTuRD]

Anyone?

 

[98 SNAKE EATER]

First off, DO NOT blow compressed air through it as too much pressure can damage the diaphragm

Here's my modulator thread with photos of what it looks like when cracked open

https://forum.ih8mud.com/threads/yet-another-dreaded-401-thread-few-diag-questions.185001/page-4

Apart from the FSM testing procedure, an easy way to tell if the diaphragm is still good is to block the PRQ ports with your fingers and gently suck/blow into the bottom port.

If it leaks or doesn't hold vacuum, the diaphragm is shot

 

[SupraTuRD]

Thanks a lot 98! I'll do the check you suggested first thing in the morning. After reading through the pages, I may have a ruptured diaphragm, as indicated by flow out the bottom port, as well as lots of carbon debris at the filter.

 

[SupraTuRD]

Well, it appears that the diaphragm is ruptured as it does not hold vacuum through the bottom port while the smaller ports on top are blocked. Is a new OEM modulator still available? If not, what is a good aftermarket substitute?