Dorman IWE's fail after 10k miles?
12-21-2015, 05:57 PM
#21
okay, I just got back home from school and had the chance to really dig into this problem. So the first thing I did was get out a vacuum tester. I hooked it up to the hose that gives the 4x4 vacuum, and I was getting 20lbs of vacuum at that point. So i removed the double hose going to the solenoid and the IWE hose and just attached the IWE hose straight to the point I had just tested. I then went to each side and attached the gauge to the hose going directly into the IWE. I am getting a full 20 lbs on both sides. So I shut the hood and took it for a drive. NO MORE CLICKING!! But.... when moving if I go over 2200 rpms you can hear one of the IWE's really grind, regardless of speed just over 2200 rpm. So I brought the truck back to the shop and hooked the gauge back up to either side and had someone rev up the engine starting at idle slowly all the way up to 4-5k. Not only was there never a drop in pressure the pressure actually went UP. The only conclusion I can come to is that one of the IWE's must have a leak that is unidentifiable until the vacuum goes above 20lbs and at that point maybe a crack opens up just wide enough to lose vacuum. Any thoughts?
See my thread here: https://www.f150forum.com/f72/how-di...m-esof-186872/
12-21-2015, 06:02 PM
#22
Senior Member
okay, I just got back home from school and had the chance to really dig into this problem. So the first thing I did was get out a vacuum tester. I hooked it up to the hose that gives the 4x4 vacuum, and I was getting 20lbs of vacuum at that point. So i removed the double hose going to the solenoid and the IWE hose and just attached the IWE hose straight to the point I had just tested. I then went to each side and attached the gauge to the hose going directly into the IWE. I am getting a full 20 lbs on both sides. So I shut the hood and took it for a drive. NO MORE CLICKING!! But.... when moving if I go over 2200 rpms you can hear one of the IWE's really grind, regardless of speed just over 2200 rpm. So I brought the truck back to the shop and hooked the gauge back up to either side and had someone rev up the engine starting at idle slowly all the way up to 4-5k. Not only was there never a drop in pressure the pressure actually went UP. The only conclusion I can come to is that one of the IWE's must have a leak that is unidentifiable until the vacuum goes above 20lbs and at that point maybe a crack opens up just wide enough to lose vacuum. Any thoughts?
12-21-2015, 06:18 PM
#23
Perhaps the solenoid itself is going bad. I just had a problem with mine. It failed completely so the system would not hold a vacuum. I could get a vacuum from the intake manifold and the IWE's worked fine if I hooked the two lines together - isolating the solenoid. New solenoid from O'Reilly's fixed er up.
12-21-2015, 06:36 PM
#24
There are check valves and a vacuum reservoir in the system that hold vacuum under conditions that would normally result in low engine vacuum. Driving at 2000 RPM, depending on the torque demand, is going to result in much different vacuum than revving the engine to 2000 RPM in neutral.
See my thread here: https://www.f150forum.com/f72/how-di...m-esof-186872/
See my thread here: https://www.f150forum.com/f72/how-di...m-esof-186872/
12-22-2015, 09:41 AM
#25
Senior Member
okay, I just got back home from school and had the chance to really dig into this problem. So the first thing I did was get out a vacuum tester. I hooked it up to the hose that gives the 4x4 vacuum, and I was getting 20lbs of vacuum at that point. So i removed the double hose going to the solenoid and the IWE hose and just attached the IWE hose straight to the point I had just tested. I then went to each side and attached the gauge to the hose going directly into the IWE. I am getting a full 20 lbs on both sides. So I shut the hood and took it for a drive. NO MORE CLICKING!! But.... when moving if I go over 2200 rpms you can hear one of the IWE's really grind, regardless of speed just over 2200 rpm. So I brought the truck back to the shop and hooked the gauge back up to either side and had someone rev up the engine starting at idle slowly all the way up to 4-5k. Not only was there never a drop in pressure the pressure actually went UP. The only conclusion I can come to is that one of the IWE's must have a leak that is unidentifiable until the vacuum goes above 20lbs and at that point maybe a crack opens up just wide enough to lose vacuum. Any thoughts?
01-09-2016, 05:06 PM
#26
Drivers side IWE vacuum leak down tested at 2inHg per minute
Passenger side IWE vacuum leak down tested at 4inHg per minute
Service manaual calls for 1inHg per minute or less
https://dl.dropboxusercontent.com/u/.../308-07A-E.pdf
I also tested vacuum on the vacuum supply hoses at the IWE with engine running in 2wd which should result in 20inHg of vacuum, and I get 0inHg at the drivers side, and only 5inHg on the passenger side.
I connected a vacuum pump to the vacuum supply line just after the IWE solenoid, and could not pull a vacuum at all.
So yep, I have a pretty good vacuum leak after all.
However, both dorman IWE's are also not holding vacuum like they should, after only 10k miles.
Passenger side IWE vacuum leak down tested at 4inHg per minute
Service manaual calls for 1inHg per minute or less
https://dl.dropboxusercontent.com/u/.../308-07A-E.pdf
I also tested vacuum on the vacuum supply hoses at the IWE with engine running in 2wd which should result in 20inHg of vacuum, and I get 0inHg at the drivers side, and only 5inHg on the passenger side.
I connected a vacuum pump to the vacuum supply line just after the IWE solenoid, and could not pull a vacuum at all.
So yep, I have a pretty good vacuum leak after all.
However, both dorman IWE's are also not holding vacuum like they should, after only 10k miles.
01-25-2016, 11:00 PM
#27
Replaced vacuum lines, and no more issues. no more clicking in 2wd. when it warms up I'll do some more vacuum tests and see if these IWE's are holding vacuum better now that they are getting some proper exercise.