HELP PLEASE !!!! CAR BREAKING UP UNDER LOAD

[anthony10210]

So I have a 15 camaro ss 1LE, it has a GPI SS3 NA cam, comp cams trunnion upgrade kit, speed engineering headers, melling LS7 lifters, GPI 7.425 hardened pushrods, K&N black hawk intake, BTR .660 dual valve springs w/ titanium retainers, and a couple other things. It’s been tuned by another tuner who i shall not name as they completely screwed my car up with putting in BS tune which ended up being so lean i could’ve cracked a piston.

anyway, i’m getting it tuned by a different tuner and i’ve been having this problem since i’ve cammed the car where it breaks up in partial load and in WOT really bad. almost sounds like fuel cut, and it will happen randomly, it’s never consistent. my new tuner logged with me and told me it’s lots of spark knock, and it seems to be ghost knock caused by possibly the camshaft being a bit too loud for the knock sensors taste, or hitting a certain frequency the knock sensors read at random rpms and load levels.

the knock sensors are completely on and never have been desensitized, however my tuner and i have came to the conclusion we may have to desensitize the knock sensors till they don’t act up anymore and cut timing. the motor is healthy, verified by pulling plugs and the fact that i feel no loss in compression or hear anything odd in the valve train. can someone please help, have any of you gone through this ? and is it quite common on a cammed car to slightly desensitize knock sensors due to this issue ?

[larry_g]

What spark plugs are you using and have you tried replacing them? Not only will it eliminate a potential cause, but it will also give you the opportunity to see if the problem is limited to specific cylinders.

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[taz1727]

First off I dont know who you used before or if you're currently using him or if you're not, but @dsmlights is the man in south florida when it comes to tuning our cars... On the flip side if you did use him and he messed up your car, you might be the first LS I've heard him mess up.
I'm running a very similar setup to yours and hes been my tuner. Same cam as you, didn't know a cam could throw off knock sensors this bad? Changing your spark plugs would be a good starting point, could have faulty injectors but that's something that a tuner can see.

[anthony10210]

Originally Posted by larry_g

What spark plugs are you using and have you tried replacing them? Not only will it eliminate a potential cause, but it will also give you the opportunity to see if the problem is limited to specific cylinders.

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i changed the plugs on the dyno, to TR6 .038 and it was STILL doing it.
we desensitized the sensors a bit and it’s still having spark knock issues. i am at 14 degrees of timing right now :/ i always use good fuel too so idk what the hell is going on. i pulled the old plugs on the dyno and verified they were ALL normal, i’m gonna replace the knock sensor tomorrow and i asked a bunch of technicians who work with me to give my car a listen, using a technician stethoscope to listen to the valve train. everyone said the car is operating beautifully in the head

[anthony10210]

Originally Posted by taz1727

First off I dont know who you used before or if you're currently using him or if you're not, but @dsmlights is the man in south florida when it comes to tuning our cars... On the flip side if you did use him and he messed up your car, you might be the first LS I've heard him mess up.
I'm running a very similar setup to yours and hes been my tuner. Same cam as you, didn't know a cam could throw off knock sensors this bad? Changing your spark plugs would be a good starting point, could have faulty injectors but that's something that a tuner can see.

it wasn’t DSMlights, i’ve heard he’s good but im with another tuner

[bottletalk]

should be easy enough to find while trending your components and marking when this is occurring...at least zeroing in on what is exactly happening. sounds like ur tuner doesn’t want to put any time into this, go with another tuner.
No offense

[anthony10210]

Originally Posted by bottletalk

should be easy enough to find while trending your components and marking when this is occurring...at least zeroing in on what is exactly happening. sounds like ur tuner doesn’t want to put any time into this, go with another tuner.
No offense

he spent 12 hours straight on the car lol, the problem is there is no trend. it’s at different places and at different times, different RPM’s from light load to WOT. it sounds like something electronic

[bottletalk]

Originally Posted by anthony10210

he spent 12 hours straight on the car lol, the problem is there is no trend. it’s at different places and at different times, different RPM’s from light load to WOT. it sounds like something electronic

it’s something electronic? Lol, that’s what trending is....monitoring your i/o data, trend the devices individually at the same time and match the pid’s with the occurrence timeline and it will narrow it down. if your tuner is not doing this you should get a second opinion.

[Greenhornet2]

You likely already did this but make sure your exhaust isn't hitting anywhere and headers aren't too close to anything. Have to make sure you aren't getting a false knock from something else first. I would do a compression check if you haven't already. If all that has checked out and you're sure my next recommendation would be to go with Ted at Jannetty racing in CT, he can remote tune and is excellent. Shouldn't have to desensitize knock sensors.

[Warship2k15]

You most likely have a different issue.Exhaust hitting something,something loose etc.
I also had a GN that had a nail in a tire that set off the knock retard sensor.
Check everything!

[InFiD3ViL]

Originally Posted by bottletalk

it’s something electronic? Lol, that’s what trending is....monitoring your i/o data, trend the devices individually at the same time and match the pid’s with the occurrence timeline and it will narrow it down. if your tuner is not doing this you should get a second opinion.

Right. A data log would show injector and pump behavior, fuel pressure (random drop?), knock detect/timing (is it retarding right after the event?), voltages, etc. You should be able to see something on the datalog exactly preceeding or after the breaking up. Then it's just a matter of filtering out the stuff that is just a reaction and narrowing it down. Obviously this is a generalization, but I'm sure you get what I'm saying.