09-F150

I just bought a 09 f150 xlt 5.4L 4x4 with 406k. The truck was maintained. It's got its obvious rockers and wheel arches to be fixed, but overall, the engine ran great and it drove great. It has thrown a code for the converter, but I'm alright with replacing that. The person mentioned an intermitent noise at a slow speed, by how he described it to me, it sounded like the iwe system. I couldn't get it to reproduce the sound as I looked it over and test drove the truck. Drove it an hour and a half home no problem. Shifted through every gear great. As I drove into the parking lot, I started coasting at a low speed and then I heard it. It's a clicking sound that starts off light and gets loud within a few seconds, then goes away. Today I start driving, no problems. Get to a Walmart parking lot, it starts to happen and I switch it into 4x4, noise went away, switch back to 2wd. Few seconds later noise comes back, and I switch back to 4x4 and it doesn't go away. This time it seemed to be a lot worse and it felt like the truck started to surge a bit, but went away and was back to normal. So I'm not sure if it was a coincidence it went away the first time. It doesn't happen any other time. I can come to a stop and drive off no problem at red lights, but if I coast for a moment the noise seems to start happening. I'm hoping it's not the transmission, but the guy mentioned he had the transmission serviced a year ago it was happening then as well, and he was told there was no issues with it at all. I know after the second time at walmart the truck threw a pending code for p0345. Would that have anything to do with this? The battery terminals do have some corrosion on them, don't know if this may also contribute to it as well, I plan on cleaning them tomorrow anyway. Any ideas on what it may be? How to test?

Spiky

Well, the most common problem in those engines is timing chain issues. And that code could easily be showing you have timing issues. So could the noise.

09-F150

And that would only show once I start to coast under 20km/hr for a moment?It doesn't happen any other time, however, it's only happened to me once the truck has been warmed up. If I pull up to a light and go its fine. Each morning I drove out of my parking lot coasting its been fine, just once I start coasting after driving for a bit, but still won't do it stopping or going from stop signs and lights. Seems to only be on a slow crawl. I can't exactly say if it's making some sort of noise when fully driving, as the all terrain tires make a decent amount of noise, plus the exhaust is loud from the tailpipe coming off.

Blue2016XL

Sounds like the check valve for the IWE (integrated wheel ends) is starting to fail. IWEs are vacuum actuated and in 2WD vacuum is applied to disengage and 4WD vacuum is released to engage. The check valve in 2WD keeps the vacuum at the needed level when the vacuum source drops. If it leaks you will get partial engagement when vacuum drops. They can work intermittently which is why you don't get it all the time.

09-F150

That's what I'm hoping for it to be is a part in the IWE system, would there be a way to test it with it only being an occasional thing? Or is it just worth it to change the check valve and see if it changes as I don't think they cost much at all.

Blue2016XL

It can be checked. You should only be able to blow through it in one direction. However, since it may work intermittently, it won't be a 100% proof of pass or fail. It is the cheapest of all the parts to replace and from your description that would be my first guess if I had already done a visual inspection of the vacuum lines and connections for cracks. Especially those connections where the rubber lines from the IWEs connect to the plastic lines on the frame.

The check valve should be on the drivers side on the firewall just below the solenoid that hangs off of the brake booster.

Blue2016XL

Also, if you have the ability to, you can do a vacuum test to see if the system hold vacuum. If it doesn't you can narrow down where the leak is coming from by isolating parts. This could also prove that the check valve is or isn't your culprit. If you do this, do not apply a lot of vacuum or you will definitely ruin one or both IWEs.

09-F150

I ended up pulling the check valve by the solinoid.it did blow both ways at first, then only one way. I noticed there is debris in the check valve. I bought a vacuum pump to test the lines. I am not sure if I was testing it correctly or not. I am know of the iwe system and have a general idea of how it works, but not 100% positive of which line is to have vacuum all the time and which ones don't. My valve, solinoid and vacuum reservoir are up by the rad on my truck. I did try to test the vacuum and it wouldn't hold, but like I said, I'm not 100% positive I was checking correctly. I did try turning the cv axel in 2wd and 4wd, both seemed like they were engaged in both settings. Not sure if the truck had to be off the ground to actually test that. I would assume that maybe the iwe actuators are done and have introduced dirt and debris into the lines causing the check valve to partially stick open. With the bladders on the actuators being done, this would also cause for my vacuum test to be correct, as I pump the handle, it rises, but then immediately drops?

09-F150

So the noise happened again, I guess not so much of a click anymore. Pretty sure the timing needs to be redone on the truck. I'll attach a video of the sound. This time I didn't stop until I shut the truck off.

09-F150

https://www.dropbox.com/s/djq7sckby9...43802.mov?dl=0

It wouldn't allow me to upload the video, so I put it in a drop box. I came up with the codes p0012 and p0022 fpr over retarded timing, pending codes from this drive. I also have p0430 fpr the converter that I already knew about. The part I don't get is if this is saying the timing is needing to be redone. Why would it only happen once warm, and only happen at low speed and low rpms. But if its stop and go traffic it's fine, only a crawl speed. I shift the truck down waited a bit and started it up and it was perfectly fine again, I started to hear it again once I got back into the parking lot at home though. It might be coincidence but if I seem to accelerate a bit it goes away.