Anyone had knock retard issues with a JLT intake?

[95R131]

I am currently working with Lund Racing on an email tune and have been having issues with +5-6 KR at 4800rpm and then slowly tapering down to +4 at 6800rpm. The car is on 93oct with a full can of VP Octanium in the tank which should bring it up to around 99-100oct.

I verified that there is no oil getting into the intake and have been going over everything that could be loose and causing false knock. The only thing that I have found that is loose is the JLT airbox. Everything is tightened down as much as it can but it still wiggles back and forth with very little effort. I ended up shoving a rag between the intake tube and the airbox to hold it more firm and the KR greatly improved. The same 3rd gear pull started at .2 KR and pulled down to -2 at 6800rpm. A 1st, 2nd, and 3rd gear WOT pull showed +0 KR in gears 1 and 2, then 3rd gear jumped to +.7 KR at 5100rpm and tapered down -.7 at the end of the pull.

Has anyone else experienced this with the JLT setup? I can't pin point any other areas that could be a issue. Is there anything else that I should look for that could be causing it? The car has 3,000 miles on it, never had the exhaust off and has a JLT 123mm intake, passenger side oil separator, VMP 67mm throttle body, 2.4 pulley with 90mm idler, and a BPR throttle body elbow.

I do have to say, Lund Racing has been a pleasure to work with thus far. During business hours, they review the logs and get back to me very fast. Just trying to get this resolved so they can finish their magic! Thanks guys.

 

[02GTKB]

A good way to eliminate if its octane related is go put 5 gallons of vp c12 or higher. You never know if that pump 93 is good until you replace it with a better fuel. I would start there, and if no change then certainly look elsewhere for false knock.

 

[95R131]

A good way to eliminate if its octane related is go put 5 gallons of vp c12 or higher. You never know if that pump 93 is good until you replace it with a better fuel. I would start there, and if no change then certainly look elsewhere for false knock.

It has since had a fresh tank of 93oct with a 32oz can of VP Octanium blended in as requested by the tuner. They feel it is not the fuel quality at this point and is most likely false knock.

 

[MastaAce03]

It has since had a fresh tank of 93oct with a 32oz can of VP Octanium blended in as requested by the tuner. They feel it is not the fuel quality at this point and is most likely false knock.

Definitely not the fuel with that 32oz can of Octanium in there. That’s good stuff. Sounds like you found the problem. Is Lund able to look at individual cylinder knock instead of global knock?


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[95R131]

Definitely not the fuel with that 32oz can of Octanium in there. That’s good stuff. Sounds like you found the problem. Is Lund able to look at individual cylinder knock instead of global knock?


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Thanks. I'm not sure if they can see individual cylinder knock or not. I sent them the updated logs this evening. I personally was just looking at the global knock in SCT Livelink.

 

[MastaAce03]

They definitely should be able to. Just ask them to switch it so you’re logging individual cylinder knock and see if it still pulls timing. I bet you it won’t.


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[2011 gtcs]

I guess worst case you can always swap your stock intake on and have Lund adjust the MAF and see if the knock goes away. But I don't think the intake has anything to do with false knock issue. What plugs are you running?

 

[95R131]

I guess worst case you can always swap your stock intake on and have Lund adjust the MAF and see if the knock goes away. But I don't think the intake has anything to do with false knock issue. What plugs are you running?

NGK BR7EF gapped at .28

 

[2011 gtcs]

NGK BR7EF gapped at .28

Same plugs I run, it can't hurt to swap the stock intake back on, Lund should be able to adjust it pretty easily.

 

[biminiLX]

NGK BR7EF gapped at .28

Should be good there. Do you have headers?
Some foam padding and adjustments with the filter bucket should get you sealed to the hood and isolated from the false knock.
Don’t you have good E85 over there? We’ve got good stuff on this side of the state.
My knock sensors are turned way down on E85.
-J

 

[95R131]

Should be good there. Do you have headers?
Some foam padding and adjustments with the filter bucket should get you sealed to the hood and isolated from the false knock.
Don’t you have good E85 over there? We’ve got good stuff on this side of the state.
My knock sensors are turned way down on E85.
-J

100% factory exhaust. Exhaust has never been off the car. E85 is around but not available enough to be a viable option to me. Most stations are 20+ miles away. I will be running 93 and Boostane daily. 8oz of Boostane Professional and 93 should bring it up to 99ish.

 

[96gt02]

Other then filter bucket being loose and able to move, do any of your hose clamps touch the valve cover? Its is somewhat common that the CAI hose clamp hammering on the valve cover with give you some false knock.

 

[Robot_trainer]

Wow, I'm amazed that something located on the inner fender can activate the knock sensors sitting in between a large chunk of cast aluminium. I've heard of headers sometimes causing this.

 

[95R131]

Other then filter bucket being loose and able to move, do any of your hose clamps touch the valve cover? Its is somewhat common that the CAI hose clamp hammering on the valve cover with give you some false knock.

I went over the entire engine, zip tied away anything that I thought may be contacting the motor. Nothing seemed to help until I shoved that rag in there. I'm going to try and secure it better with the rubber grommets from the bottom of the factory box and some vacuum line around the hole in the airbox.

 

[95R131]

Well, I went through and added some padding to tighten down the intake. It is very firm now and barely wiggles at all. Unfortunately I am still seeing random +2.5-4.5 KR. Usually starting right around 5000rpm. This is driving me nuts. There is absolutely nothing that I can find that would be tapping on the motor. I got under the car and the exhaust is completely tight, no bolts or pipes are any where near in contact with anything. What else could possibly be causing this?

 

[me32]

Have you tried going back to a stock intake?

 

[95R131]

Have you tried going back to a stock intake?

No, not yet. Lund would have to write a new tune for that unless I took everything off and went back to stock.

 

[CobraBob]

Sucks when an engine with various mods starts to produce an issue like this. Diagnosing/finding the culprit and resolving it can be time consuming and frustrating. And then, as in your case, to go back to the factory intake to rule out the JLT intake means you have to get a new tune. I feel your pain bro!

 

[JPs2013GT500]

I think I had knock issues with my JLT carbon fiber 127mm intake:
https://www.svtperformance.com/threads/finally-made-some-headway-on-my-knock-issue.1153824/

I say think because the tune was obviously adjusted at the same time I switched to the PMAS intake and the knock was reduced. Months later I can say the knock comes back from time to time with the PMAS & its tune as well. I've checked everything I can get to, multiple times. Had mechanics look it over, etc.. Everything looks good.

However it still occasionally pulls some timing. At this point I figure it simply must be variations in the fuel quality I'm getting.

 

[95R131]

I think I had knock issues with my JLT carbon fiber 127mm intake:
https://www.svtperformance.com/threads/finally-made-some-headway-on-my-knock-issue.1153824/

I say think because the tune was obviously adjusted at the same time I switched to the PMAS intake and the knock was reduced. Months later I can say the knock comes back from time to time with the PMAS & its tune as well. I've checked everything I can get to, multiple times. Had mechanics look it over, etc.. Everything looks good.

However it still occasionally pulls some timing. At this point I figure it simply must be variations in the fuel quality I'm getting.

Thanks for the info. It definitely is frustrating. My knock did improve after tightening the air box but still isn't perfect. It seems a lot of people have these troubles with these cars looking at past posts. Every post I go to most of the people never resolved it. I wonder if more people are actually having similar issues and just aren't looking at their logs? My fingers are crossed that it is just winter gas and it will improve come summer. I don't have my hopes up though. I dumped another 8oz of Boostane into the tank and still get the same KR. Is it possible that I need to reset something in the computer to get it to adjust?