IWE Test.. Now at a Loss

[Millwoodva]

Rattle/grind when modulating on acceleration.
Tests preformed:
1. Noise stops in 4AWD
2. With vehicle running and both both wheels off the ground they spin freely at the hub.
3. 20" vac to solinoid.. both solinoid and tranfer case actuator "click" when switched to 4AWD.
4. By-passed solinoid with new hose from vacuum source directly to IWE actuators. Drove and noise still present.
5. Actuators hold 15" vac for 30 minutes.
6. Spun wheels with vacuum attached to IWE.. no pressure loss.

Any thoughts greatly appreciated.
Jeff

 

[sjwelds]

Somewhere in your system should be a check valve. Sounds like it's failing and is allowing a low vacuum condition to exist during acceleration. This is the reason bypassing the system won't fix it. Not enough vacuum during acceleration to hold the iwe's open....

 

[Millwoodva]

Ok.. so with the vacuum gauge in sight while driving should prove this theory correct?

 

[Millwoodva]

I have new hose connected directly to the IWE hub actuators and pulling 20" of vacuum from the EWI solinoid vacuum source. With the vacuum gauge spliced inline and in sight while driving. While in Park.. 20" on the gauge. When revving the engine.. vacuum goes to Zero.
Also while driving.. slight throttle pressure sends gauge to Zero.
(unable to attach video from my phone)
Oddly on this test drive, with the only difference in the by-pass arrangement was the vacuum gauge placed in line..
The rattle/grinding was much less noticeable..

Is the vacuum gauge going to Zero while accelerating what I need to chasing ???

 

[Kenerator]

https://www.blueovaltrucks.com/tech...d-to-know-about-the-iwe-system-and-then-some/ Maybe this will help with your troubleshooting. Also I recommend a smoke machine. Invaluable for finding vacuum leaks.
Good luck!

 

[riphip]

Check the vacuum hose assembly behind the battery. Motorcraft #YF32

 

[Hamfisted]

Sounds like you're missing a check valve in the main vacuum supply line from the intake manifold to the IWE solenoid.




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