Engine Pinging

I have a 2011 Wrangler Sport that I have upgraded wheels from the stock 26" to 33". Ever since I have engine pinging at when I first take off from a stop, sometimes from transmission kickdown. I have since calibrated my speedo, replaced the stock paper air filter with a K&N, and used my Flashpaq 5.0 to set up for 91 octane. still happening. Thinking about getting a cold air intake. Do I need to go to a dealer to have my engine re-mapped? Or, is this just a common problem with the 3.8? Any suggestions would be helpful.

 

How many miles? Possible an exhaust leak, lifters. Bigger tires is like putting a load on the motor. It will accentuate something that was already there that you didn't notice before.

 

Just my quick 2 cents. If your not using 91 octane. Then don't set it up for that. Today's engines respond very well to lower octanes. Set it up to what your using. 87 is the most common.

I agree with OFFGRID post. Look for leaks. Especially exhaust leaks. XJs were known for exhauste manifold leaks. Which I did experience being a former XJ owner. And it does steal mpgs, rpms, and overall performance.

To support OFFGRID. Look for leaks. And reprogram your 'puter to what you are actually running.

 

I'm with JKBob on the 87 octane thing, but I know what he's doing. The programmer will advance the timing to the point of detonation. This should increase the compression increasing power, but to stop the detonation you have to run higher octane. This will put more stress on the motor. I suggest that you keep everything as stock as possible until you figure out what your pinging is. Fix that, then starting tuning you motor. Build on a good foundation.

 

I am running 91 which is why I set the computer for it. My JK only has 50k on it so I didn't think to check for exhaust leaks. Should I set it back to 87 even though I'm running 91? I'm getting 16+ MPG in town. I don't notice the pinging until it is fully warmed up. ???

 

Is your check engine light on? Do you have access to a scanner to check for codes. Some codes will show up even when the check engine light is on.

If your motor is designed for 87 octane run 87 octane. There is no benefit to running any higher octane. Motors that are tuned to higher performance are forced to run higher octane because they will have detonation with lower octane fuels. Running higher octane does not give you any more performance if you are set up for 87.

If your programmer is setting you up for higher octane fuels I would guess that it is changing the timing and probably the air/fuel mixture for a higher performance. In newer cars this can be done electronically. In older cars this was all done with a screwdriver, wrench, and a timing light. In any case this will most likely shorten the lifespan of your motor because of the added stress you put on it which it was not designed for like other cars let's say (Porsche, corvette etc).

 

Read this.

http://www.roadandtrack.com/new-cars/car-technology/news/a18008/premium-fuel-futures/

 

I have no check engine light or any codes. Interesting article and I thank you for your help. Here's an interesting fact I just read in my owner's manual, "light spark knock at low speeds is not harmful to your engine." Huh...guess I was making something out of nothing after all. Oh, and by the way the manual also states no methanol or ethanol blended fuels. I will be on the hunt for local gas stations that sell ethanol free fuel.

 

That is what the article said about light pings also. Ethanol burns colder than gasoline so that might accentuate that pinging you mention. Good luck on the ethanol free fuel.

 

I have found a couple stations here in the Boise area that sell "real" gasoline. It's like buying premium all over again.

 

Great all worked out and the pinging wasn't a major issue. I was about to ask a lot of questions that OFFGRID answered.
Please don't take this the wrong way. Just trying to save you a couple bucks. Stick with the 87 octane gas. Your going to get the best performance from your Jeep as close to "off the line" , stock, as possible. Several members here helped me with several other questions I had as far as performance is concerned. And they were right. The extra cash your paying at the pump. Is not worth it. And you could be putting that towards other upgrades. Lol. These cars / Jeeps these days don't need or do they perform better with the extra octane.

Just a PS. Yes, as OFFGRID stated. Back in the day you could get a little better performance with a screw driver and a timing light. And yes, your car would run some what better with the higher octane fuel and advancing the timing. But you would bjrn more fuel. They even sold "octane boosters" at one time. Go to any auto parts store now. And you will not find these "octane additives". Why....because they don't work any longer. And their a waste of money.

My point being. Run what your rig was set up to run. Just like oil. Don't run a thicker, 10 /40. When you should be running 5 / 20. Just just hurting and cutting short your motors life. Again....just my 2 cents.

 

Understood. I was one of those old school hot rodders at one time. The days of tuning with a screwdriver and timing light are over. If I had my way we would still be running carborated V8s with distributors. The biggest thing I got out of this discussion is that 87 octane is the best for my vehicle but it should be methanol and or ethanol free. I am lucky we still have a couple stations locally that offer "real" gas. It is a little more expensive but I will do what I must to get the best performance out of my JK. I will have to plan my road trips a little better looking for good gas. Thanks guys!!!

 

You just dated yourself Marty. Lol. Hope I didn't offend you. And I'm about to date myself. I'm with you. I'm an old school weekend warrior motor head. My first car was a 67 Chevy Caprice with two extra doors. But it had a small block 324/350 horse 4 bbl. Which of coarse being a kid. I sank a ton of money in in it. Edlbrock intake, cam, lifters etc etc, and a Holler 750 double pumper. Dude, that thing was fast. My Dad swore I'd kill myself in it. But I would race it every now and then. And of coarse I would turn up the timing, throw some octane boost in it and pray I had the brakes to stop.

My second car. A 69 Impala that had a 283. I pulled the 324 from my Caprice and dropped it in. Now Man....that car could run.

Again Marty. Hope I didn't offend you. And I am with you. But cars today. I learned Run best what their set up for. As another member said to me. Car manufacturers are under so much pressure to get their vehicles to get x amount of this and that. Stock is best for performance.

 

I gotcha man. I don't offend that easily. I gravitated to Jeeps because I' an old school Mopar guy. Darts, Barracudas, Coronets. I had a factory 70GT Dart Swinger with a 340 six pack. Picked it up in a used car lot when I was in the service for 1500 bucks. I could down shift into 2nd at 60 and still make the tires yell at me. I'm new to the Jeep thing. only had it for a couple years. Drive train is stock. If I was going to bolt on any power adders where would I start? Intake, ignition,...?

 

Staying naturally aspirated, You might get added power with a K&N airfilter, but for offroading I trust the paper elements more for keeping trash and moisture out. I don't think there is much that you can do to greatly improve performance on todays Jeep engines and stay naturally aspirated. That being said I have a friend who for roughly $5k purchased the RIPP supercharger kit, and installed it in 1 day. He can now smoke 35s in 4WD. I have been researching the cost of an LS 6.0 swap into a JKU and I think I have the whole swap down under $10K including a Chevy truck 6.0/6spd automatic and an Atlas transfer case, but that is only if I do it myself.

 

Peter, will you adopt me. Lol. I promise I won't be a pain in the ass and I will behave myself. As long as you let me help with your builds. Lol.

I'm a huge fan of Fast n Loud and Diesel Brothers. I'd love to do crap like that.

Back to the thread. I've done a lot of research. And as OFFGRID stated. Your best off to leave it stock. And, I have looked into turbo kits. A little expensive, to say the least. And as it turns out. I'd rather keep my Jeep stock. Not looking to go fast these days. Just save some gas money. Lol.

 

I guess I will save up for front and rear lockers and leave the engine alone. Thanks guys!

 

In the front I would run a selectable locker Like Eaton's new E-locker. I really like it and have been running it with no problems for 2 years now. I run a detroit locker in the back. If your getting lockers, you might as well regear since youre there and for that matter if you regear that means bigger tires and taller lift, and new you lost all your power because your running 40s 5.13 gear and dang now we are back to the question, "Do I install a Supercharger, or do I just go LS/HEMI swap?"