Everything You Wanted To Know About The IWE System....And Then Some!
#91
02-03-2019, 08:00 PM
Remember the 4WD engagement or lack there of is considering that you shift motor on the transfer case is working properly.
If you suspect that your system is malfuncting and you are not able to test it right away or want to drive and not damage anything, disconnect the line coming off the intake at the check valve and plug both ends of the line. This will not allow any vacuum to reach the system and leave your hubs locked in all the time. This is fine and wont cause any damage as long as the hubs lock correctly. The half shafts and front driveshaft with the front differential will turn but the 4WD will not be engaged. You might notice a drop in MPG, but it is now safe to drive.
I hope that my investigation into the system and explination helps alot of people understand the system and help troubleshoot it. Anybody feel free to add to this, but i think i covered it pretty deeply.
This is a rough layout of the IWE vacum line system. From what i can gather and understand from the vacuum system for IWEs, there are two check valves and when working correctly and without any leaks in the vacuum system they hold the vacuum to the IWEs at a constant vacuum even thoguh the vacuum will change at the intake with engine load and RPMs.
If you suspect that your system is malfuncting and you are not able to test it right away or want to drive and not damage anything, disconnect the line coming off the intake at the check valve and plug both ends of the line. This will not allow any vacuum to reach the system and leave your hubs locked in all the time. This is fine and wont cause any damage as long as the hubs lock correctly. The half shafts and front driveshaft with the front differential will turn but the 4WD will not be engaged. You might notice a drop in MPG, but it is now safe to drive.
I hope that my investigation into the system and explination helps alot of people understand the system and help troubleshoot it. Anybody feel free to add to this, but i think i covered it pretty deeply.
This is a rough layout of the IWE vacum line system. From what i can gather and understand from the vacuum system for IWEs, there are two check valves and when working correctly and without any leaks in the vacuum system they hold the vacuum to the IWEs at a constant vacuum even thoguh the vacuum will change at the intake with engine load and RPMs.
#93
06-06-2019, 10:43 AM
I've got a 2019 Raptor and through some testing, I found that I'm having this IWE trouble and hoping for some thoughts and answers to my message to follow. I joined a Raptor forum and posted this same message and the only answer I got was "why do you want to do this to a brand new truck?" Nobody has been any help there and it seems like people here actually care about an issue and want to help. Ok so here is the message I posted on the Raptor Forum......I just bought my Ruby Red 2019 Raptor a few months ago and love it!! I traded a 2018 Lariat for it that was having what sounded like a wheel bearing issue that nobody to could diagnose....which leads me to this post. Now, I understand it's a Raptor and it's got low gears and if you can afford one, why worry about gas mileage, right? So when trying to diagnose my Lariat problem, I asked the mechanic riding with me if it was possible for the front axles to be making the noise I was hearing and he said "that's impossible because the front axles don't turn while in 2WD". I'm always interested in seeing how things work, so I take the truck home, jack the front up, start the truck in 2WD and what do you know....the front axles are turning just like he said they wouldn't. So I do some reading to figure out how this IWE system works and find that the vacuum solenoid is not opening as it should and not unlocking the front hubs as it's suppose to. Now....fast forward to the Raptor since I traded the Lariat for it.......I rotated my own tires the other day and thought.....what's the chances the axles turn on this one in 2WD too. Sure enough, I fire up the Raptor, spin the front wheel and the axle is turning! I'm very puzzled. So here is what I did......I unhook the solenoid totally and just plug the vacuum hose directly from the check valve to the hose leading to the IWE's on both sides. Think I'm crazy but with the hubs actually unlocked and not spinning that extra drivetrain weight, I went from 16.3 mpg to 17.5 mpg going to work with the cruise set at 75 as always. What a huge gain! I don't quite understand how the solenoid system is suppose to engage but something seems out of place. I tested the plug and it's showing 12.56 volts to the solenoid....perfect! here's the issue though.....I turn the truck on (not starting), I go out and blow through the bottom vacuum port and the valve is open like it should be. If I start the truck, the solenoid valve is closed and not pulling vacuum on the IWE line at all. Can anyone please explain to me why starting the truck turns the solenoid off??? Maybe there's something else that takes place while driving that finally opens the solenoid again??? I'm not sure what series of actions has to take place in order for this to work properly. I'm convinced that the IWE solenoid is not pulling vacuum at all otherwise my mpg wouldn't have went up. I thought the ground was bad to the solenoid so I shave off enough wire coating and use a pair of alligator clips to ground the wire properly and all the sudden, while the truck is running, the axles are not turning and the solenoid is working again. All good until I get in the truck and and the dash has a notification about 4WD system failure! I unhook the ground I made and it goes away but then the solenoid closes again as well. So here's my fix option.....I'm going to use one of the auxiliary switches and run a positive connection to the solenoid and ground to the body at the closest firewall ground, order a pigtail so I don't cut up the factory plug and power the vacuum solenoid located on the drivers side firewall with an auxiliary switch. I leave the switch on to power the solenoid and unlock the hubs and when I need 4WD, turn of the switch and use the 4WD selector. Is this a good idea or bad? I know that if I go to the Ford garage and explain to a certified mechanic what is wrong and how it should work, I'm going to get laughed at and likely never get a resolution to an existing problem. I know Ford has had it's failures with the IWE issue and maybe I'm going out on a limb to say that the system is meant to fail so that the front always stays engaged so that the clicking noise never happens to current trucks? I mean c'mon.....you buy a new truck, who jacks it up to see the the hubs actually unlock? I only did because I was told it doesn't turn in 2WD and I had to see it for myself. Sorry for the long winded message but I'm aggravated over the issue and hoping someone else has seen all this too.
#94
11-02-2019, 12:45 AM
can anyone confirm that my IWEs are bad before i go through the work of replacing them?
05 FX4, 150k-ish miles on it.
last year one wheel started not engaging when it was below freezing. as soon as it got up to 35* or so and started to thaw out, the 4wd engaged and worked fine. this spring the 4wd started getting really hit or miss. now it wont engage at all and just makes the grinding noise. if i jack the truck up in the air everything seems to work normally (both wheels spin in 4wd, only 1 wheel spins in 2wd)
05 FX4, 150k-ish miles on it.
last year one wheel started not engaging when it was below freezing. as soon as it got up to 35* or so and started to thaw out, the 4wd engaged and worked fine. this spring the 4wd started getting really hit or miss. now it wont engage at all and just makes the grinding noise. if i jack the truck up in the air everything seems to work normally (both wheels spin in 4wd, only 1 wheel spins in 2wd)
#95
06-09-2020, 02:18 PM
Check valve
After my recent experiences with the complete IWE system i decided to write up a description of the system and troubleshooting. Hope this helps out some people!
Maybe this can become a sticky!
When the system is working correctly, vacuum is placed on the system unlocking the hubs while the truck is running. When shifting to 4WD vacuum is relaesed, locking in the hubs. A vacuum leak at any part of the system can cause failure.
When the engine is started and running, vacuum is exerted on the entire system, unlocking the IWE actuators. When the engine is turned off or 4WD is engaged (either by floor shifter of dial selector) vacuum is released by the IWE solenoid to the actuators at the wheels. So vacuum to the actuators at the wheel unlocks the hubs for 2WD and release of vacuum by the solenoid locks them for 4WD.
When the vacuum builds when the engine is started, the vacuum from the intake via a vacuum line exerts vacuum on the entire IWE system all the way to the actuators. The first check valve locks the vacuum at the highest vacuum that is exerted from the engine from that check valve down. The vacuum box now holds that highest vacuum exerted also. The second check valve located right before the IWE solenoid holds the highest vacuum to the actuators from what has been exerted from the engine.
As you start to understand the vacuum system and series of check valves, you will see that the vacuum box that is located between the two check valves does in fact act as a reserve. When you engage the 4WD, vacuum is released by the solenoid and locks the line from the solenoid back up, the release happens from the solenoid and to the actuators. This process allows the lines and vacuum box between the two check valves to hold the current highest vacuum even though the engine vacuum is constantly changing and the vacuum from the second check valve to the actuators have been lost. When 4WD is disengaged, the solenoid is opened back up, the high vacuum from the reserve from the vacuum box is then used to then exert vacuum on the lines to the actuators unlocking the actuators no matter what the vacuum from the engine is. When this little bit of vacuum is lost in the reserve it is then rebuilt from the engine when vacuum is increased from the intake.
After saying all of that and you think about what the manual says about turning the 4WD on and off, you notice that you are supposed to activate and deactivate the 4WD while under a certain speed and while not accelerating. This ensures two things, high speed engageing and disengaging of the gears in the hubs which can cause mechanical damage does not happen. It also allows a quick window of no load and low RPMs from the engine, hence high vacuum from the engine, that will quickly replenish the high vacuum to the entire system and "locks" that vacuum between the two check valves and reserve box for the reserve, as well as from the second check valve to the actuators.
This, when working correctly without any leaks always ensures a high enough vacuum to keep the acutuators unlocked when your in 2WD, or unlocking quickly when shifting from 4WD to 2WD. A leak in one of the lines,the reserve box, or an actuator, or a faulty check valve will allow a leak down in vacumm somewhere in the system that will allow the actuators to possible try to engage or close to it when not needed while driving, giving you the grinding or whinning noise of the gears of the actuators trying to mesh together at highway speeds.
Maybe this can become a sticky!
When the system is working correctly, vacuum is placed on the system unlocking the hubs while the truck is running. When shifting to 4WD vacuum is relaesed, locking in the hubs. A vacuum leak at any part of the system can cause failure.
When the engine is started and running, vacuum is exerted on the entire system, unlocking the IWE actuators. When the engine is turned off or 4WD is engaged (either by floor shifter of dial selector) vacuum is released by the IWE solenoid to the actuators at the wheels. So vacuum to the actuators at the wheel unlocks the hubs for 2WD and release of vacuum by the solenoid locks them for 4WD.
When the vacuum builds when the engine is started, the vacuum from the intake via a vacuum line exerts vacuum on the entire IWE system all the way to the actuators. The first check valve locks the vacuum at the highest vacuum that is exerted from the engine from that check valve down. The vacuum box now holds that highest vacuum exerted also. The second check valve located right before the IWE solenoid holds the highest vacuum to the actuators from what has been exerted from the engine.
As you start to understand the vacuum system and series of check valves, you will see that the vacuum box that is located between the two check valves does in fact act as a reserve. When you engage the 4WD, vacuum is released by the solenoid and locks the line from the solenoid back up, the release happens from the solenoid and to the actuators. This process allows the lines and vacuum box between the two check valves to hold the current highest vacuum even though the engine vacuum is constantly changing and the vacuum from the second check valve to the actuators have been lost. When 4WD is disengaged, the solenoid is opened back up, the high vacuum from the reserve from the vacuum box is then used to then exert vacuum on the lines to the actuators unlocking the actuators no matter what the vacuum from the engine is. When this little bit of vacuum is lost in the reserve it is then rebuilt from the engine when vacuum is increased from the intake.
After saying all of that and you think about what the manual says about turning the 4WD on and off, you notice that you are supposed to activate and deactivate the 4WD while under a certain speed and while not accelerating. This ensures two things, high speed engageing and disengaging of the gears in the hubs which can cause mechanical damage does not happen. It also allows a quick window of no load and low RPMs from the engine, hence high vacuum from the engine, that will quickly replenish the high vacuum to the entire system and "locks" that vacuum between the two check valves and reserve box for the reserve, as well as from the second check valve to the actuators.
This, when working correctly without any leaks always ensures a high enough vacuum to keep the acutuators unlocked when your in 2WD, or unlocking quickly when shifting from 4WD to 2WD. A leak in one of the lines,the reserve box, or an actuator, or a faulty check valve will allow a leak down in vacumm somewhere in the system that will allow the actuators to possible try to engage or close to it when not needed while driving, giving you the grinding or whinning noise of the gears of the actuators trying to mesh together at highway speeds.
Spoiler