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Part Throttle Knock

stevnoof1

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1st and 2nd. All over the place tip in tip out randomly in rpm range. Usually just a quick blip around 0.5-2.0 sometimes increases or holds steady till I let off but I'm never really in the gear long enough. Never happens in other gears. Happens probably 25% of the time.

I have shared logs with my tuner when I have had knock under wot after a shift like during 1/4 mile runs. This happens every now and then and it did get worse when I had a xpipe that was installed poorly and leaking bad. When the wot knock happens it will go somewhere between 0.5-6.0 and hold steady until I let out. I was told that it is false knock. Never had any knock on a single gear pull. Last time at the track didn't have many of these occurrences, maybe one gear on one or two runs.

Never mentioned the part throttle 1st and 2nd gear knock to my tuner because I thought it might just be normal or also due to false knock. I did ask to have a few revisions done nothing really changed.
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ManBearPig

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The fact that yours is so random makes me question if maybe some of it is false. Have you ever tried some race gas or octane booster to see if that made it stop?
 

stevnoof1

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I have added some Sunoco gt plus once Only like 2gallons I had laying around. I have a flexfuel tune so I switch between e85 and 93. Haven't noticed a difference between any type of fuel.
 
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ManBearPig

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I flashed back to the stock tune to get some logs at lunds request. I was sure the knock would go away but I'm still seeing it in pretty much the exact same conditions. Now I'm wondering if it really may be false.
 

Tommy V

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At wot and the knock continues through the rpm band that is usually not false knock,that's a sign of detantion.Especially if the knock steps ups as your rpms increase.On the log if your seeing your knock Continue to step up as rpm goes up that is good sign of detonation,U need to be careful.
 

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dubster99

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Sounds like you need some better tires if you're spinning 3rd that hard n/a. Definitely dump in some octanium and see if it goes away. How much knock are you seeing on the stock tune?
 

BMill705

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Ive had knock issues on my datalogs for months. I was about at the point where I was going to sell everything, go back to stock and trade the car in. Well I recently was able to correct it. From my experience I can tell you the knock sensors on these cars are crazy sensitive. I suggest you start with your exhaust, even the slightest leak that couldn't be heard at idle was one of my causes. Next check under your hood and look for ANYTHING that looks loose or touching something ,it doesn't matter if its metal or plastic. For example I installed a UPR catch can and noticed an increase in knock again after fixing my exhaust leak. I found the return line valve tapping against the coolant reservoir which was causing knock at WOT and part throttle.
Couple more things I corrected that lowered the knock readings were my nitrous lines, so I wrapped them all in high temp wire coil. The large wire adapter near the pcm was leaving marks tapping against the pcm. Lastly poor quality gas showing around .80 to 1.00 and after adding octanium I now see no knock at WOT. Hopefully this helps you.
 

v8hgt

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Are you running an oil catch can? If so try removing it and remove the plastic engine cover for a bit. I’ve noticed my catch can could under extreme conditions vibrate in its mounting and I suspect that was the cause of my false knock.
 
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ManBearPig

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I do have an oil separator...the Ford racing plastic one. It seems to work well and is pretty solidly mounted.

I'm seeing similar activity on the stock tune as the Lund tune. Mostly blips of .5 or so as I roll into the throttle after a shift. Every now and then it will go over a degree, sometimes as much as 2. I'm still not sure if it's false or not.

I'm going to try some octanium. Obviously if it still knocks with octane booster on the conservative stock tune it's false.

The only exhaust related component I can think may cause an issue is the fact that my cat delete pipes are solid (no flex pipe) and therefore the whole exhaust is pretty rigid. Granted it's mounted in rubber hangers in the rear so it's not getting any vibes from the body, but the entire system is essentially solid with no flex. Could that possibly cause a problem with false knock.
 

BMill705

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I do have an oil separator...the Ford racing plastic one. It seems to work well and is pretty solidly mounted.

I'm seeing similar activity on the stock tune as the Lund tune. Mostly blips of .5 or so as I roll into the throttle after a shift. Every now and then it will go over a degree, sometimes as much as 2. I'm still not sure if it's false or not.

I'm going to try some octanium. Obviously if it still knocks with octane booster on the conservative stock tune it's false.

The only exhaust related component I can think may cause an issue is the fact that my cat delete pipes are solid (no flex pipe) and therefore the whole exhaust is pretty rigid. Granted it's mounted in rubber hangers in the rear so it's not getting any vibes from the body, but the entire system is essentially solid with no flex. Could that possibly cause a problem with false knock.
Removing the flex pipe wouldn't cause any knock but look it over and be sure it's not too close to anything. I had a shop make mine and while it looked ok, under load it was shifting enough to hit against the transmission Crossmember.
 

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ManBearPig

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Removing the flex pipe wouldn't cause any knock but look it over and be sure it's not too close to anything. I had a shop make mine and while it looked ok, under load it was shifting enough to hit against the transmission Crossmember.
I spent an hour under the car tapping everything with a rubber mallet a few days ago. The exhaust does resonate when I bang on it but no real rattles. It's not touching the body, crossmember, or anywhere front to back. The clamps are not hitting the body either. The only thing I notice is that when I bang on certain areas of the exhaust, something in the bellhousing rattles. I suspect it's just the flywheel, or maybe the springs in the clutch disk or something. It's pretty minor and I have to think it's normal. Aside from the exhaust being very rigid (as in the exhaust tips shake around when the car idles) it seems fine. No rattles or witness works from any contact anywhere.
 
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ManBearPig

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I guess the knock I'm seeing must be false. It still knocked on the stock tune, and it is knocking on the Lund tune with octane booster. I flashed my Lund tune back in at the gas station while I was pouring the octanium in. I guess I should've tried octane booster fuel on the stock tune also but I'll bet the results would be the same. I just don't know what else I can check on the car. I'm on stock headers, stock catback, everything seems to have plenty of clearance.
 

stevnoof1

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I wish I could test mine on the stock tune. It seems like we are experiencing a similar problem for sure. I might try to take off my catch cans I have the ford driver/passanger side ones. Who knows what will help at this point.
 
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ManBearPig

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I took off my catch can and engine cover. Nada. Found one of the motor mount bolts slightly loose and got excited thinking for sure I had found it. Tightened it up and still no difference. Banging around on the exhaust I do notice some resonance that sounds like it's coming from the mufflers. I've read that others have had problems with the MBRP mufflers coming part internally do I pulled the whole catback off and ran down the street on open headers with my off-road leads. Talk about loud. It only took me a mile to determine that was still no better so I went back home. I'm out of ideas.
 

stevnoof1

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Just wanted to say after the header install I have had almost no part throttle knock. Still having some random after hard shifts though. But part throttle knock seems almost under control. I only noticed it happen once around 3k in 1st gear when the power surged a bit. It went 0.5 then 1.0 before I shifted to 2nd. It also happen on one tip in 1st. Used to happen all the time. Not sure what you can do to check the stock headers but it might be worth investigating.
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