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Old 03-03-2012, 02:34 PM   #1
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Default Never ending KR issue

I've run out of options on this issue. Countless time talking to boosty, countless posts all over. Lots of suggestions, no fixes. Just to bring you all up to date. This problem has not changed after 3 engines. Nothing left. After a trans rebuild and 3 different torque converters. All new sensors. And more changes to the tune then I can count.

I would be driving along and with cruise on and get KR, some times up to 15* I dropped the timing down to single digit, no change. No boost at this time, even removed the SC belt. Finally, I adjusted the KR in the area I keep seeing it. Only when cruise is on with torque converter locked. After a lot of experimenting, I got it down to a very small window. Right about 1900 rpm. I can drive with cruise set at 60, and I will get a few degrees, set it at 61, nothing, set it at 59, nothing. I'm convinced it'* my front motor mount, which is solid.
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Old 03-03-2012, 02:57 PM   #2
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So your suspecting false KR with the front mount? Maybe yours is too SOLID. Didn't you drill a hole in that awhile back and stiffen it up with a bolt?

Based on your post, I'm safe to assume this high KR only happens at X MPH?

If so, I'm wondering if your car is generating a harmonic via just about any rotating object in the car. This can include RF generated devices. Last I knew, knock sensors are designed almost like a crystal.(radio). Thus the possibility of false RF knock.
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Old 03-03-2012, 03:19 PM   #3
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My thoughts exactly. I also see it at a lower speed, but then I'm in 3rd gear, locked TC, and 1900 rpm again. So my thought is 1900rpm is just the right vibration to set off the knock sensor, a little higher, or lower and nothing. If it was true KR, I should have been able to tune it out. But when I drop timing from mid 20s, to about 9, and no change, it'* not real. Bill even sent me a PM a while back that a local guy has the very same problem. But I have spent the last few months testing this. If I do see KR at 61 or 59, its like 0.1* and then is gone.

And yes, a case 10 bolt, 1/2" It'* solid.
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Old 03-03-2012, 03:36 PM   #4
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If we have determined it to be false knock, then we need to figure out where it is coming from. With that front mount being very SOLID. The transfer of vibrations are going to be amplified due to loss of that rubber bushing. Vibrations coming from where? Transmission, tires, rotors, driveshafts etc.
But you did narrow it down to almost a certain RPM, 3rd and 4th gear with TCC lockup. Can you command your TCC to lockup in first gear and see if you can duplicate it at 1900rpm again? Or 2nd gear?
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Old 03-03-2012, 03:37 PM   #5
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I forgot to post this link while replying the last time. Possible good reading material...

http://home.netcom.com/~bsundahl/kno...tm#spectrogram
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Old 03-03-2012, 07:06 PM   #6
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I could, but not worth the effort. Before numbing down the KR in that area, I was able to get it in the shop not even moving. As for the vibration, I believe it'* just normal engine vibration at that RPM.
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Old 03-03-2012, 09:24 PM   #7
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Does your car have 2 knock sensors like mine? If so, could you try running on one sensor (disconnect the other) and scan for KR at different conditions? Then try it just running on the other sensor. If you get more knock on one sensor than the other, it might help you to understand what area the false knock is coming from. I only mention this because I know you are running out of things to try.
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Old 03-05-2012, 02:45 PM   #8
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Post up a picture of that front mount again. Todd at Intense had further mods and locked his engine down solidly. I made a fairly solid mount and never even got vibration. Tengis on a few forums is selling a kit now that welds to the subframe and attaches much like our stock front mounts, but with a totally solid piece of metal. I'd think he'* running into the same issue if it was from the mount. How does your TA mount look when you torque the motor, those are common for hitting the body. Dogbone underneath as well.

I was never able to get any real KR with my 97 as a 97 (PCM/wiring) or as a 99 (99 pcm and wiring, that you current have....did you try that yet?) Funny thing is..I'm seeing a lot with my Regal, that looks like PE needs to be adjusted. (no time)

Are you running a wideband? If so..what'* your AFR where you see the KR? That area is going to be low rpm, high load and potenitally not in PE if you were asking for power due to it being low throttle %.

Consider plugs and gap as well. You can run too big of a gap and blow out the spark if there is any boost at those points. You can also run too hot, too small of a gap etc. I've recently seen older coils that sometimes break down like the MSD'*. As well, what wires are you running and how old are they? Are you only seeing KR, or misfires as well?
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Old 03-05-2012, 11:20 PM   #9
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That mount is a hockey puck, 3 I think. So that'* not touching, and I changed that after I had this problem, no change. Only mount not changed is the rear trans mount.

I've tried different coils, and no misfires. No boost, I got same thing with belt off. Plugs are new, autolite 103 gapped at .045 if I remember right. Wires are MSD, a few years old.

My wideband sensor died a while back, never replaced it. I can get KR at 1900 RPM, really don't mater the speed, as long as it'* cruising at 1900 rpm. Even got it in the shop when not moving.
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Old 03-06-2012, 12:07 AM   #10
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Following along as I hope to someday be able to contribribute to this.
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