Unsolvable Knock Issues

Wissam Hatim

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Hey everyone.

Friend has encountered a very weird problem recently. I will try post as much information as possible and list all steps from A-Z. To begin with the car is a 2014 Mustang GT. The owner, my friend, baught a Paxton 2200 kit, with ID1000's, kooks long tube headers, the air intake upgrade, rxt clutch and BAP all at the same time, and proceeded to install them on a bone stock 2014 GT. After installing the mods, he began the remote tuning session with a tuner that is well trusted by the coyote crowd and that is known to do good work. After completing the remote tuning, all was great. The car made approximately 650whp on pump 93 and no hickup whatsoever.

Now came the fun part, my friend took his car out for a drive. Went WOT in second gear, car pulled hard, and as soon as he shifted into third gear and got back on the throttle the car felt gutless. He quickly pulled out his laptop. Repeated the pull and found the ECU pulling alot of timing as soon as he shifted into the next gear, you will find logs attached to the thread. He repeated the process, this time after shifting into third and as the ECU pulled timing, he would let of the throttle and go WOT again in third, the car would run perfectly again through third gear.

He began inspecting everything he could. Couldn't find the source of what seemed to be fake knock. He returned his car to 100% stock, and on a stock tune, he found the car not adding as much timing as it should. On the stock tune, we expect the knock sensor to read -6 degrees, meaning no knock is detected and the ECU is adding its maximum amount of timing. However this was not the case even with high octane fuel. It would not add more than 3 degrees of timing (so read -3).

At this point we went on to perform a leak down test. All cylinders showed approximately 8% leak, which we believe to be a normal number. Except cylinders 5,6 and 1, which all showed 0% leak, even after cranking the engine a few turns and trying again.

I have attached logs to this thread, and hope a few could chime in with suggestions. The car is tuned on SCT. I appreciate any help with trying to resolve this issue, its been a couple of months with no luck.
 

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5lho

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I feel your pain. I went through this with my 2012 Vortech car. Something is creating it. It's pulling a shit load of timing here. Now, it seems to be gradually adding it in so, it might actually be real. Try some higher octane fuel with real octane booster like Torco or Lucas, or race fuel like C16 (A few gallons of leaded race fuel won't ruin anything and will determine for sure if it's fake or real) or retune for E85, if you have it. If that fixes it, it was real KR.

When I finally got my 2012 running decently, I wrecked it so, when I replaced it with a 2014, I sold on the blower and went with a nice, simple nitrous setup and I've been totally happy with it. If I ever go blower again, it'll be PD, for sure, with the biggest goddamned HE I can get.
 

basspro302

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Did you preform a crank relarn after the clutch? If not try that.

I would relearn the crank sensor, clear the kam memory (disconnect the battery on both ends hold the 2 teminal ends together for a couple minutes. Then flash the pcm back to stock file the reload the custom tune.
Also after you reconnect the battery and load the cutom tune let the car idle with all loads off to let the car relearn the throttle body.


Also check all pipes, exhaust clamps for signs of rubbing or hitting which can cause false knock.
 

Wissam Hatim

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Did you preform a crank relarn after the clutch? If not try that.

I would relearn the crank sensor, clear the kam memory (disconnect the battery on both ends hold the 2 teminal ends together for a couple minutes. Then flash the pcm back to stock file the reload the custom tune.
Also after you reconnect the battery and load the cutom tune let the car idle with all loads off to let the car relearn the throttle body.


Also check all pipes, exhaust clamps for signs of rubbing or hitting which can cause false knock.

We have tried the relearn, reflashed to stock and double and tripple checked in the install in detail. We are quite unsure now. Going to try a tune with a different tuner but doubt it will solve anything.

Thanks for the advice.
 

clinton2003

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I was getting some false knock, I looked at my knock sensors, and my passenger side was a bit loose. Tightened both down, and my knock returned to normal.

something you can check. also check for anything that may be hitting, header, exhaust, mufflers, etc. if anything can vibrate metal on metal, those sensors could be picking it up.
 

Vlamison Araujo

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Its been a while but might be able to help you/your friend or someone else. I have paxton setup with kooks long tubes headers. Kooks includes some clips that goes between long tubes and x/h pipe bolt to help bolt from backing out. Well the shop who installed my headers installed those clips. When i went to log, my car was catching positive 3 knock. After 1 week tracking it down i went under car and those clips rattle on exhaust, because they stay loose. I removed them and logged again, no more knock. So if you havent solved your issue, try removing those clips if you havent so. Also check if the maf pipe isnt touching the thermostat clamp, which was another issue i ran 2 yrs ago. Good luck.
 

Adam Krigbaum

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Ive seen this mainly with procharged stangs. But it happens to alot with aftermarket intakes aswell. Whenever I did a pull and shift my knock sensors would go to +6 and stay there until the pull was over. Check your Intake because most of the time its hitting on the fan cover or some plastic stuff. This also happened with Alex Flores white vortech s550. This should fix your issue. Lmk if it does
 

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