False knock between shifts?

w1tchblad3 said:

Yes mine will show knock when parked and I stab the throttle or while I’m driving and stab the throttle. I do not have stock drive shaft. I have a solid one piece.

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What's your exhaust setup?

One other thing I've noticed with mine is it won't KR when the engine is cold. It starts to happen around 165-175 degrees. I'm not sure if the knock sensors are not active below that temp, or if this a potential clue?

Have you ever put a scan tool on it to see which knock sensor is reading the knock? Last time I did this it was the passenger side sensor reading all the knock.

yeah mine will not knock when cold either . I have kooks headers off road x pipe and stainless works cat back exhaust. I have not checked to see which sensor is active.

Looked at the logs you definitely have alot of knock. Can you do a log with spark advance?
If you have one knock sensor on the scan tool showing knock it’s probably only on that bank not noise from a loose bolt pr something.

Your lambda looks ok but i would try swaping the afr sensors side to side and look at it on the scan tool see if the knock switches to the other bank.

Then try and swap all 4 injectors bank to bank may be a faulty flowing injector. They are hard to pick out in fuel trims and afr sensors they can mask themselves and make it hard to diag.

I would also swap the plugs around check the gaps

It also could be interference from another component such as a coil or injector putting noise in the circuit. Only way to see that tho is with a lab scope.

w1tchblad3 said:

yeah mine will not knock when cold either . I have kooks headers off road x pipe and stainless works cat back exhaust. I have not checked to see which sensor is active.

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The KR when hot only is very interesting, and may well be the sensor is just not active until a certain temp, who knows. This is a question i've asked many times, no one knows the answer.

I have stock exhaust with the exception of a lethal off road H pipe for comparison.

basspro302 said:

Looked at the logs you definitely have alot of knock. Can you do a log with spark advance?
If you have one knock sensor on the scan tool showing knock it’s probably only on that bank not noise from a loose bolt pr something.

Your lambda looks ok but i would try swaping the afr sensors side to side and look at it on the scan tool see if the knock switches to the other bank.

Then try and swap all 4 injectors bank to bank may be a faulty flowing injector. They are hard to pick out in fuel trims and afr sensors they can mask themselves and make it hard to diag.

I would also swap the plugs around check the gaps

It also could be interference from another component such as a coil or injector putting noise in the circuit. Only way to see that tho is with a lab scope.

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Hey thanks for taking a look.

Swapping the 02 sensors - That would mean the KR is happening because of what the 02 sensors are telling the ecu? I always thought the knock sensors ONLY responded to a "noise or vibration".

Fuel injectors - They were bought and installed brand new as of last year. Yes there could be a low flowing one. But would that explain why the KR only reads when throttle is stabbed? If i ease into the throttle all is well.. Happy to try this is we think it's a worth while time investment?

Plugs - I installed a brand new set, no change.

Interference - Interesting thought. No clue how i could isolate this.

Log Spark Advance - Not sure how to do this. I have the lund ngauge and use there log option. Anyone know if i can add that on?

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At this point i'm really certain it's NOT SOMETHING RUBBING / TAPPING. As i have 1 thousand zip ties holding every damn thing that could make any sound in place. I've screwed with the exhaust more times then i can count. I've disconnected the belts, blower, etc.

We are going to put the scan tool on it tonight again. Before we just revved it to see which knock sensor was showing knock. Tonight we plan to take it out for some test hits to see what it's showing us. I'll let you all know what we find.

On the electrical interference - If i unscrewed that one knock sensor, and left it connected to the wiring harness, but kept it from touching anything, i suppose that would test the electrical interference possibility? Meaning if it still shows knock while not connected to the block / touching anything while revving, gotta be an interference?

Update - Scan tool showed KR readings on both sensors pretty evenly.

While on the lift, we noticed the rear wheels have some play in them when gripping at 12 and 6, or 3 and 9 and wiggling. I've noticed a squeak at lower speeds from the driver rear wheel as well, and a bit of a clunk over bumps.

We were banging on the exhaust again and something is definitely loose in one of the stock mufflers ( i have a set up bassinis as well, switched to stockers to confirm the KR is not from bassinis). Also noticed a slight exhaust leak where the H pipe joins with the over axle pipe on one side. With the clamps cranked down as much as it would go, still seems a little loose.

I was going to buy lethal over axle pipes anyways, so i just went ahead and ordered them.

I'll continue to update as i have more information. Hoping to solve this soon!

Kman11 said:

Update - Scan tool showed KR readings on both sensors pretty evenly.

While on the lift, we noticed the rear wheels have some play in them when gripping at 12 and 6, or 3 and 9 and wiggling. I've noticed a squeak at lower speeds from the driver rear wheel as well, and a bit of a clunk over bumps.

We were banging on the exhaust again and something is definitely loose in one of the stock mufflers ( i have a set up bassinis as well, switched to stockers to confirm the KR is not from bassinis). Also noticed a slight exhaust leak where the H pipe joins with the over axle pipe on one side. With the clamps cranked down as much as it would go, still seems a little loose.

I was going to buy lethal over axle pipes anyways, so i just went ahead and ordered them.

I'll continue to update as i have more information. Hoping to solve this soon!

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Had multiple issues with the lethal h pipe, clamps and exhaust leaks because of it. Just weld it man. Much cheaper than the OTAs and you will probably still have the same issue.


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Kman11 said:

Update - Scan tool showed KR readings on both sensors pretty evenly.

While on the lift, we noticed the rear wheels have some play in them when gripping at 12 and 6, or 3 and 9 and wiggling. I've noticed a squeak at lower speeds from the driver rear wheel as well, and a bit of a clunk over bumps.

We were banging on the exhaust again and something is definitely loose in one of the stock mufflers ( i have a set up bassinis as well, switched to stockers to confirm the KR is not from bassinis). Also noticed a slight exhaust leak where the H pipe joins with the over axle pipe on one side. With the clamps cranked down as much as it would go, still seems a little loose.

I was going to buy lethal over axle pipes anyways, so i just went ahead and ordered them.

I'll continue to update as i have more information. Hoping to solve this soon!

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Anymore updates to this?

w1tchblad3 said:

Anymore updates to this?

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I put the lethal OTA's on, no change in Knock retard. Sounds better though!

After doing some more testing here are some new facts -
* Can't get it to KR in 1st gear, hard to get it to KR in 2nd gear.
* 3rd and 4th gear pretty easy to see KR, even with a slight throttle tap
* Can't get it to KR in 5th gear either.

KR always starts after the car is warmed up / driven for a bit. When i first pull away from the house there won't be any issue.

So it seems the KR is speed dependent - Faster i'm going the more likely to see KR, except for in 5th which is odd, unless it's because 5th doesn't rock the car as much as 3rd/4th.

We're pretty certain the rear wheel bearings are toast. There's a bit of play, along with some clanging sounds. Thinking this may be the culprit. We're going to tear into it this week hopefully and see what happens.

Sorry been busy at work/life. Just a thought if it was my car i would pull they entire exhausy off just run open headers and make a hit to 100% rule out exhaust. Just this past weekend i was doing a bunch of pulls back to back and the rear mufflers are expanding from the heat and started rubbing on the frame it would go away whem the exhaust cooled down.

What mods are on the car?

I have the same issue. Pretty frustrating at this point as I've been under the car about 5 times this weekend trying to trace down any metal to metal contacts with no success. Car seems to like to add timing on the initial gear but like OP it knocks when going into the next gear. Can Do WOT pulls in 2nd and let off gas and it won't knock but if I go 2-3 it will spike and kill power for the next gear. Lund sent me a revision capping the KR to 2 since I added some octane booster with no change so it's a little less robbing but would still like to find the cause.

Car is a procharged 2014 P1X with full exhaust.

I just bought V8 K-Member Brace with Engine Torque Limiters Part # CHE7L for 2005-2014 Mustang to eliminate the chance that the motor is torquing over and hitting but I can't see where it is from underneath.

Canadian5.0 said:

I have the same issue. Pretty frustrating at this point as I've been under the car about 5 times this weekend trying to trace down any metal to metal contacts with no success. Car seems to like to add timing on the initial gear but like OP it knocks when going into the next gear. Can Do WOT pulls in 2nd and let off gas and it won't knock but if I go 2-3 it will spike and kill power for the next gear. Lund sent me a revision capping the KR to 2 since I added some octane booster with no change so it's a little less robbing but would still like to find the cause.

Car is a procharged 2014 P1X with full exhaust.

I just bought V8 K-Member Brace with Engine Torque Limiters Part # CHE7L for 2005-2014 Mustang to eliminate the chance that the motor is torquing over and hitting but I can't see where it is from underneath.

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I saw your post on my facebook thread about this same topic. The engine brace is an interesting idea.. For me, i have the stock exhaust manifolds, so how can anything be banging? I've looked 100 times and don't see any possibility of it, but who knows.

Someone did respond to my facebook post and said he has the same knock issues and it ended up being a bad tensioner pulley.

I'm going to give it another month of trying things, at that point i'm throwing in the towel and putting back to stock / selling.

Lund never offered me a tune with limited knock like that, what the hell!! LOL.

basspro302 said:

Sorry been busy at work/life. Just a thought if it was my car i would pull they entire exhausy off just run open headers and make a hit to 100% rule out exhaust. Just this past weekend i was doing a bunch of pulls back to back and the rear mufflers are expanding from the heat and started rubbing on the frame it would go away whem the exhaust cooled down.

What mods are on the car?

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Yes i agree that's a good idea i will try it.

It's a d1 procharged with 3.9 pulley, wastegate at 10psi, stock headers, stock intake mani, meth 50/50, offroad h, lethal ota, AB's, full after market suspension ( BMR, viking, strange).

Recheck your crank pulley for the procharger also if its not installed correctly it can rattle around. Take it off and reinstall it per procharger install manual.

basspro302 said:

Recheck your crank pulley for the procharger also if its not installed correctly it can rattle around. Take it off and reinstall it per procharger install manual.

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That's been on my mind as well. That was an issue when I first installed the kit (we were dumb and didn't tighten it down enough). But we did end up getting it on there and all has been well, car made good power on the dyno. I guess I would need a new crank bolt if I did that as well?

basspro302 said:

Recheck your crank pulley for the procharger also if its not installed correctly it can rattle around. Take it off and reinstall it per procharger install manual.

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I have an ati balancer so it's a simple pulley bolt on.

Do you have the pcv the way procharger recommends it? I have it the way they recommend it and I recently noticed my discharge pipe leaking oil from blow by and the pcv. I know oil can reduce the octane rating of fuel. I plan on switching it or a catch can.

basspro302 said:

Do you have the pcv the way procharger recommends it? I have it the way they recommend it and I recently noticed my discharge pipe leaking oil from blow by and the pcv. I know oil can reduce the octane rating of fuel. I plan on switching it or a catch can.

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I have a catch can on it.

I put the new OTA's on, no change. Also changed the tensioner on engine to rule that out.

My rear wheel bearings are shot. Going to fix that this week see if it's related.

Hoping for the best.

Were you able to fix it? I have the same problems. I have a 2012 mustang 5.0 p1sc1 procharger stage 2. Get the same reading as described. Big headache. Been going with it with Lund also and can’t seem to find the problem. I posted on Facebook a while ago about it. Someone said it can be my throwout bearing? What’s the chances on that? Any updates?