LSX Tuners, need help determining detonation with HP Tuners scan files.

[Rybar]

Hey guys,

My car has been making an extremely annoying rattling noise. I'm at my wits end trying to figure what it is. Weve pretty much checked everything without tearing into the motor. The tranny and clutch are brand new, motor and trans mount brand new. We've checked headers, exhaust and pulled the whole dash apart with no luck.

So I'm trying to figure if it's detonation. What baffles me is the car and tune were fine for quite a while, and then one day this noise just appeared and then went away only to come back.

I just did a couple scans with HP Tuners yesterday and recorded some crappy phone videos and and trying to figure out if the noise is detonation or not.

If you have HP Tuners, please view these files and tell me what you see.

Here are some other threads with more info, and the Scan and DTC files that you can download.

http://www.ls1tech.com/forums/general-maintenance-repairs/1123475-rattling-noise-when-accelerating-higher-rpm-h-c-ls1-69-camaro.html

http://www.ls1tech.com/forums/pcm-diagnostics-tuning/1351896-can-someone-please-check-my-hp-tuners-scan-file.html

http://www.lateral-g.net/forums/showthread.php4?t=29331

http://www.hptuners.com/forum/showthread.php?p=237375#post237375


http://www.youtube.com/watch?v=QI3E41FWN6c


http://www.youtube.com/watch?v=QI3E41FWN6c

[Rybar]

No suggestions or help??

I now see the most KR I had was about 3.9

I think the noise seems to be something mechanical rather than detonation.

These screenshots of the KR may help:

https://static1.pt-content.com/images/pt/2010/11/ss1-1.jpg
https://static1.pt-content.com/images/pt/2010/11/ss2-1.jpg
https://static1.pt-content.com/images/pt/2010/11/ss3-1.jpg
https://static1.pt-content.com/images/pt/2010/11/ss4-1.jpg
https://static1.pt-content.com/images/pt/2010/11/ss5-1.jpg

[greatwhitebuffalo]

I Had the same problem with my 2000 camaro LS1. It would make a detonation noise (rattling) only at full throttle, while the motor was under a load (like on a dyno). I tried higher octane fuel, timing etc with no luck. Turns out I had some push rods that were slightly bent maybe only couple thousands. This deflection in the valve train caused the detonation sound. When I did a cam change I replaced the push rods and valve springs with heavier, stronger parts and fixed the problem. Just an idea.

[Rybar]

I Had the same problem with my 2000 camaro LS1. It would make a detonation noise (rattling) only at full throttle, while the motor was under a load (like on a dyno). I tried higher octane fuel, timing etc with no luck. Turns out I had some push rods that were slightly bent maybe only couple thousands. This deflection in the valve train caused the detonation sound. When I did a cam change I replaced the push rods and valve springs with heavier, stronger parts and fixed the problem. Just an idea.

Did your motor still seem like it was running fine and power levels ok? And my noise comes on and then goes away in the upper rpm range. What rpm range did yours make the noise?

[killer67]

Paging Mike Norris!!! PM him if he does not see this -he uses Hp Tuners and could answer your question

[Rybar]

Paging Mike Norris!!! PM him if he does not see this -he uses Hp Tuners and could answer your question

What's his username??

[camcojb]

What's his username??

his username is..................... Mike Norris

https://www.pro-touring.com/forum/member.php?5802-Mike-Norris

[Mike Norris]

Thanks guys. I just replied to your PM Rybar. I am out of the country in Panama till Nov 20th, yes it is work related, and will be checking the web about every other day as it is available.

Mike Norris

[greatwhitebuffalo]

Rybar... My motor made the noise in the mid to high RPM. When I put my car on the dyno (I also would suggest you do, it makes It easier to locate a mechical issue) I could hear it coming from under the valve covers. It sounded like the spring were going to come shooting out of the motor! I also used HP tuner to pull some timing out of the motor because I thought it was detonating this did not work. The noise also did not effect the knock retard. What do you have done to the top end of your motor? Parts, miles etc....

[Rybar]

Rybar... My motor made the noise in the mid to high RPM. When I put my car on the dyno (I also would suggest you do, it makes It easier to locate a mechical issue) I could hear it coming from under the valve covers. It sounded like the spring were going to come shooting out of the motor! I also used HP tuner to pull some timing out of the motor because I thought it was detonating this did not work. The noise also did not effect the knock retard. What do you have done to the top end of your motor? Parts, miles etc....

Hey thanks for the reply. I think this is the next step after I look at the tune. For mods: I've got ET Performance 215cc Heads w 60cc chambers, HS rebuild stock rockers, Comp 850-16 lifters and Trend custom pushrods with .40 Cometic Head gaskets and a Ported Fast 90/90 all of these parts have maybe a couple thousand miles. The Cam is a TSP 233/239 112 cam and when I did the cam swap I put in a new LS2 timing chain and sprocket and LS6 ported oil pump. These parts maybe have a couple thousand more miles on them. The motor is running about 11.5:1 compression.

[Mike Norris]

Hey Rybar,

I just got web access with my laptop instead of just a 3G iPad and was able to download the files and take a quick look. I do not see KR all the time but it seems it does rattle hard under decent accel, but not necessarily WOT. The car is running very lean at cruising speeds as the fuel trims are compensating anywhere from +15% to as much as +40% at times. The timing table just has a big block of 28 degrees of timing in the higher load tables, which is fine if it wants it, but there is a severe step to that 28 degrees from somewhere around 15 degrees.

I will look a lot more closely, but I would say the tune really needs the VE and MAF tables dialed in and the clean up the timing tables. I would also be curious what the wideband A/F ratio was at WOT during the dyne runs or on the street.

Hope this preliminary info helps a bit for now and when I get a chance I will look a little deeper. Let me know about the A/F ratio though.

Mike Norris

[Rybar]

Thanks Mike, I'll ask my tuner what the A/F ratio was during the dyno tune. I remember him saying he was setting it "safe" but the number slips my mind.

Do you think this noise could be mechanical like something loose or bent in the valvetrain??

[Rybar]

Mike he says it was 12-12.5

[Rhino]

I'm not sure if I can hear anything on the video. All I think that I'm hearing is something tapping the mic on the camera.
While I can't directly help, 12 to 12.5 is pretty safe while in PE. With that said, once you enter PE, your trims lock to current values, or zero, whatever is the greater value. It's still possible to have your fuel trims high while maintaining a safe AFR.

I haven't had a chance to look at the log, but from what Mike's said, I would have to agree that I would start back at the VE tables then MAF. once the final trims were down within 1 or 2% I'd start chasing a potential spark issue. In my experience, some areas of the spark table can take a ton of timing, others may only accept 1 or 2 degrees before knocking. It's also pretty easy to take a blanket change one column too far.

As far as a mechanical issue, it's very possible. I've been chasing a valvetrain noise in my DD that's driving me nuts. Some pretty common sources of valvetrain noises (other than incorrect preload) are lifters tapping valve covers at high RPM with high lift, pushrods rubbing within the heads, bent valve, or bent pushrods.

The first two are pretty rare on a motor that's been together for quite some time. Have you recently over rev'd the engine or made any changes with it or fuel system?

[Mike Norris]

Mike he says it was 12-12.5

Any chance he gave you a print out of the before and after runs with the A/F reading on it? No offense to them, but I trust a print more then just what someone says. More so after seeing the logs & tune.

As far the noise being mechanical, just to hard to say and I am along the lines of what Rhino mentioned.

Mike Norris

[Rybar]

Thanks guys, I don't recall the dyno shop giving us a print out. This tune is originally a mail order tune from Texas Speed for my cam only setup, then sent to Speartech to run stand alone and finally once I changed the heads, intake and valvetrain I had a local buddy of mine do the dyno tune for max power. So the car has never been tuned for driveability or anything on the street. Once the PCM does it's learning the car actually drives/idles really well.

My buddy is not a massive expert and only did it to help me out. So I don't really have a shop or tuner locally that I can take it to to make the changes or fix the problems.

[Rhino]

I'm assuming you have access to HPT since you have the tune and logs. I may be able to send some material your way that will allow you to pick up the basics of VE tuning.
I wouldn't say I'm anywhere near an expert, but a few books and DVD's I found, in addition to the HPT forum, has helped lessen the learning curve. As long as you have the desire to learn I'm certain you'd be able to get it.

Otherwise, you can still do some testing with it. If you feel it's spark related, I'd download a stock tune for your motor and copy out the high and low octane tables from a stock tune and drop them into yours. You'll likely be down on power, but it's simply a test. If the stock tables resolve the issue you're probably doing down the right path. If the noise is still there, it's likely mechanical in nature.