Friday2322

My Jeep is a 2010 JKU Rubicon, 35's, auto, 4.10's and about 21k miles.

I noticed last month when I driving on the highways in Colorado when my RPM's would get over about 4,000 I could hear a lot of pinging. It sounded like it was on the right side of the engine, at least from inside it did. That is the only time I ever hear it do that, I first noticed it a year ago, again in the mountains at high RPM. I use 87 octane gas at home, in Colorado I had to buy the "mid-grade" fuel to get 87 or slightly higher. I am running the 87 tune on the Superchips and my JKU is an auto. Any ideas? or should I try another higher tune with higher octane fuel? After noticing this the first time I started to pay attention and noticed it occurs at lower altitude also, but it's not quite as bad.

Also, when I was on a couple of easier trails at higher elevation (over 11k feet) a couple of times I heard the engine knocking, at least that's what I would call it. It happened right after I had to climb over something fairly steep and I was stopped and not applying any throttle. It also sounded like the right side of the engine, from inside the cab. It wasn't a fast knock and it wasn't loud at all but noticeable, a slight tap of the gas pedal and it was gone. It sounded pretty sturdy, like knocking on a heavy oak door at a medium pace. I checked my oil, 5W30 conventional, and I had not used a drop and it still looked clean. No lights or gauges went off and the coolant temp had never moved and was in the middle. I have never noticed it at lower altitudes. I have no idea what to make of this and with everyone talking about bad engines I'm a little worried, but I'm not sure I should be since it's not a regular thing.

I looked for the knocking issue in the forums but couldn't find one just like mine, or what I thought was close to mine. Any thoughts you guys can give on this one would be appreciated. Thanks

Krynn

I noticed the exact same thing when I went to Colorado a few weeks ago. Slightly different setup with my Jeep though... it's an '08 X with 3.21s and a 6-speed, fairly stock for the moment. Not running any kind of aftermarket tune. Anyhow, when I got to Colorado, I didn't think much of what fuel I was tanking up with. And then I noticed my engine was knocking pretty bad, especially at higher RPM under a heavy load. So I decided to bump up to the middle fuel grade, and that's when I noticed that the mid-grade fuels in the mountains are the same octane as the low-grade fuels back home. And after that, there was no more knocking, not even when heading up steep slopes at altitudes close to 13k.

I'd guess your Superchips tune pushes the tolerances a bit over what is stock, which is why you were probably still getting some knocking at high altitude even though you were running 87 octane. Next time you're planning on playing around at those altitudes, maybe fill up with 91 before hand? Or try some octane-boost additives?

Ryan0260

There are many reports on superchips programmers causing spark knock. That would be my guess. Do a search for the threads on here pertaining to this

efan450

I would guess a lean condition coupled with lower octane fuel was causing spark knock. The reason I suspect its a lean condition is both of you said you were in high elevation and both were on 87 octane...krynn, you say your mostly stock..do you have any kind of aftermarket intake that would further lean your mixture? Imo I always want my jeep running top notch when i'm wheeling so I always run premium when hitting the trails, just to avoid any possible spark knock.
Friday, have you tried running 91-93 on your 87 tune? Will waste a little $, but will verify if its spark knock, when you hit that trail again...just some suggestions...hope neither of you hear it again

Friday2322

I'm not running any engine bolt on's, such as CAI, TBS, etc. I haven't tried the higher octane tunes yet but will.

Yeah, the fuel there runs a couple points lower than at home, the low grade stuff was like 85 octane and the mid was around 87-88 octane, which is what I was buying.

The higher RPM pinging is definetly a ping not a knock. That's been going on since I had the Jeep I just never thought that much of it because I try to stay out of the 4,000+ RPM range. But after hearing everyone complain about it I wasn't sure what to do or how concerned to be.

The knock is just that, a knock, and I've only noticed it while idling and not under any load. Like I said earlier, it's sporadic, and I only heard it a couple times throughout the whole trip. It concerns me more than the pinging.