DEALER SAYS MILD SPARK KNOCK

[Badgertits]

no recirculated blow off valve on the turbos, Truck performs perfectly, Ultimately I may just have to deal with it but its more obvious in the cab of the truck and its just unnerving, not to mention embarrassing on a $73000 truck

If I start noticing this myself now I'm blaming YOU lol!

 

[jamanrr]

I do not know what the boost pressure of our trucks are, I do know what the sports cars I have owned have been. I had an Eclipse GST when it came out and it would chirp like that under wide open throttle. I would imagine 15-20 lbs of boost is going to make some sort of noise, and whether it is recirculated or not it will make some sort of noise.


The energy has to go somewhere, vacuum or back into the intake itself. I have not looked closely at it as I have not heard this noise on my truck. I do know that turbo damage can happen when the back pressure is allowed to build up when you let off the boost at full pressure. I would imagine Ford uses full ball bearing turbos for their center cartridges. I am not sure if they are twin scroll or not.

 

[RustyNutz]

I dont know know if it helps, but I noticed my 18' 17k mile make very similar, which I noticed greater after an MPT 93oc tune. I even submitted a support ticket, because at 4500+ rpm, esp in 2nd and 3rd gear, it has a very similar squeak/rattle noise. They looked over my logs and showed everything looks proper. Knock sensor is showing OK, and it seems milder than a knock. I have started to think its a sqeaky wastegate connecting rod, or like you guys say something to do with blowoff/recirc noise.

Now I want to test mine in 4a...You've got me thinking it might be something losing vacuum pressure (from being in boost/away from vacuum for so long)

 

[Anthony Palazzolo]

Makes sense about the wastegate rattle, could be! I forgot to tell Y'all that on the the 3rd and 4th pass at WOT its all good !!!!!! NO RATTLE!!! could that be because the wastegate linkage tolerances are a bit sloppy and with the intense heat produced by multiple passes could possibly tighten up those tolerances hence minimizing rattle? or is the truck adjusting timing? but if that was the case then it would repeat the rattle upon new start up like after an errand. Just Dunno

 

[FordTechOne]

I haven't messed with the IWE system on this truck, but I believe that when vacuum is removed from the system, it engages the hubs?
Vacuum drops off when you put a heavy load on the engine, so there may be something going on with the IWE system.

Correct. If vacuum is removed, the hubs will engage.

 

[RustyNutz]

[could that be because the wastegate linkage tolerances are a bit sloppy and with the intense heat produced by multiple passes could possibly tighten up those tolerances hence minimizing rattle? or is the truck adjusting timing? but if that was the case then it would repeat the rattle upon new start up like after an errand. Just Dunno

Mine does seem different though. The cold-startup wastegate linkage rattle is different from my WOT noise, IMO.

Mine has a pretty clearly defined buzzy rattle at cold startup for 1-2 minutes, then goes silent.

**EDIT - This video is informative, but not what this thread is about, my mistake**

 

[White raptor]

I used to get a funny sound that sounded like detonation at WOT at about the same rpm with my MPT 93 tune I tuned it back to 91 and never heard it again.

 

[isis]

Mine does seem different though. The cold-startup wastegate linkage rattle is different from my WOT noise, IMO.

Mine has a pretty clearly defined buzzy rattle at cold startup for 1-2 minutes, then goes silent

They’re not the same thing.

 

[RustyNutz]

It just sounds like a chirping sound from 5k to shift. My truck does it along with a few others I’ve found online. Only at that shift, no others. Same rpm range as well.

Nice video Antho. Have you tested in 4a?

Not to hijack, but on mine, I tested and confirmed last night my rattle/noise is ONLY present in 2wd, not 4a, and only after 3-5 seconds of WOT (so no vacuum for some time, mostly high RPM 2nd and 3rd). I found TSB 20-2189 which describes pretty perfectly what OP and I are both experiencing, and i have scheduled an appointment with my dealer.

That sucks the other dealers aren't in agreement OP. Look up that TSB workflow, and maybe have a trusted indi mechanic do the vacuum testing, to find out conclusively for yourself if it is IWE vac loss or not. IMO any spark knock is a no-no, and the PCM's datastream monitors and records spark knock sensor activity, so it should be simple to see if the sensor is actually detecting what you are hearing. BUT not happening in 4a makes me pretty confident that it is an IWE vac and not a knock situation.

 

[moonjim]

As far as the spark knock goes i had that and narrowed it down to spark blow out. ive tried different plugs but its there at high rpms/full throttle. So don't know how to fix.