Regular gas spark knock

[robx251]

I have been noticing lately that I am getting some spark knock when lugging lowish rpms. Around town and put playing, Multiple tanks of fuel from different stations. It did clear up when I am running premium. I have the 3.8 with 105k on it.

Anyone else notice this? I have recently done a complete tune up. Plugs, wires, intake cleaning, and top end clean.

 

[jeeeep]

did you use stock plugs?

mine would ping when it was new, I installed a Scream'n Demon coil and Firepower wires - no more ping

if you have a tuner you can change the tune but then you'd have to run a higher octane gas all the time

 

[TRLJNKY]

Ive got 140k on mine and it does the same thing if I run 87 octane. I run 91 and it seems to do a lot better. Ive done all plugs, wires, cleaned intake ,etc as well. I just chalked it up as cheap gas and carbon deposits. Ill follow this to see how many of us are out there with this issue

 

[robx251]

I did use stock plugs. I just have the procal, used it for tires and such. Every thing else is stock

 

[wayoflife]

I have been noticing lately that I am getting some spark knock when lugging lowish rpms. Around town and put playing, Multiple tanks of fuel from different stations. It did clear up when I am running premium. I have the 3.8 with 105k on it.

Anyone else notice this? I have recently done a complete tune up. Plugs, wires, intake cleaning, and top end clean.

Just to verify, you are running 87, correct?

 

[robx251]

Just to verify, you are running 87, correct?

Yes 87 with the dumb ethanol blend. 10%

 

[wayoflife]

Yes 87 with the dumb ethanol blend. 10%

Hmmm, I wonder if it's the ethanol. I've seen it happen on older Jeeps and where 91 would clear things up.

 

[robx251]

I'm not sure, unfortunately the eathonal blend is all that we can get out here.

 

[WJCO]

I've had 3 vehicles that I've used BG 44K on (which you can now get at Oreillys, used to be only distributed to shops) and it cleared up pinging right away. Not sure if you are having some unseen carbon deposits, but if you are, that stuff works great. Pour it in a half tank of fuel and fill up the rest of the way if I remember right, very easy to use.

 

[Jeepers46]

I have the same issue. 08 3.8 with 60,000 miles, stock plugs and plug wires. If i run 87 octane i get the noise, run 91+ and it quits. So i just keep using the 91-93.

 

[Ghettomedic]

Here we are 2023 and still doing that same noise if I use 87. So I started using 93

 

[bobfriesenhahn]

Thread resurrection!

NYC is something like -3 feet elevation right?

93 octane is not available everywhere. In some poor rural areas, 89 is the best available and regular is something like 86. It is very satisfying to find a pump which works. I even encountered a town where all they had was one pump with regular gas.

There are two things you can do to solve hearing the noise: #1 turn up the music, or #2, move out West to a high-elevation area like Colorado. I recommend option #2 since it does not rule out option #1.

 

[Ghettomedic]

Thread resurrection!

NYC is something like -3 feet elevation right?

93 octane is not available everywhere. In some poor rural areas, 89 is the best available and regular is something like 86. It is very satisfying to find a pump which works. I even encountered a town where all they had was one pump with regular gas.

There are two things you can do to solve hearing the noise: #1 turn up the music, or #2, move out West to a high-elevation area like Colorado. I recommend option #2 since it does not rule out option #1.

In 7 years I’ll be able to move out from this cesspool. 7 years and I’ll retire from nyc fire dept

 

[bobfriesenhahn]

In 7 years I’ll be able to move out from this cesspool. 7 years and I’ll retire from nyc fire dept

One more year for me. I already put my foot in the other place 6 years ago.

Do you hear the ping/knock at idle? Under medium acceleration? Firm acceleration?

My 2.0L sounds like a cement mixer at idle, and very light loads, but it never stumbles, pings, or knocks when going up mountain grades or similar activities where octane makes a difference. The only time I heard what sounded like pinging is when going down a long 7% grade and trying to slow entirely using engine braking. Maybe I was sold bad gas.

If your engine is actually pinging or knocking, maybe there is something wrong with the knock sensor, which is used to detect pinging.

 

[cozdude]

One more year for me. I already put my foot in the other place 6 years ago.

Do you hear the ping/knock at idle? Under medium acceleration? Firm acceleration?

My 2.0L sounds like a cement mixer at idle, and very light loads, but it never stumbles, pings, or knocks when going up mountain grades or similar activities where octane makes a difference. The only time I heard what sounded like pinging is when going down a long 7% grade and trying to slow entirely using engine braking. Maybe I was sold bad gas.

If your engine is actually pinging or knocking, maybe there is something wrong with the knock sensor, which is used to detect pinging.

If there was a knock sensor issue the cel would be on. Very vital part to the engine and the ecm would know

 

[Ghettomedic]

I actually found a guy who used to work for Chrysler back in the day early 2000. He was a computer engineer and designed the software for these engines. He told me straight up fca is doing a lot of disservice to jeep wrangler owners particularly 3.6 engine platform. Even in the manual it says light knocking is no concern. So fca straight up to expect that. So I asked him what is his recommendation. His reply was run a 93 and be done with it.

 

[rich67]

Had the knock on my 13 with 137k miles for a couple years. It clears up whenever I put non-ethanol in it (Sunoco and some Circle K's here in Florida sell it). This ethanol crap is what causes it to be more pronounced. Using an octane boost additive didn't do much to help it. Using the non-ethanol for a couple tanks so far, it's pretty much gone.

 

[jeeeep]

Had the knock on my 13 with 137k miles for a couple years. It clears up whenever I put non-ethanol in it (Sunoco and some Circle K's here in Florida sell it). This ethanol crap is what causes it to be more pronounced. Using an octane boost additive didn't do much to help it. Using the non-ethanol for a couple tanks so far, it's pretty much gone.

i always use non-ethanol when I can, makes the Jeep happier.

 

[Ghettomedic]

I have experienced this engine knock after approx 2k miles of ownership of a brand new jeep. So I was told by my dealership to just use a 93 fuel and engine knock was gone. I took a trip to Florida and in the way back I was getting that engine knock even on a 93 fuel. Gassed up at multiple locations same engine knock. I went back to the dealership and was told I’ll be needing a new engine rather soon. I said okay that fine as long as I get a loaner. The manager laughed in my face and said we can’t give you a loaner because it can take months before they get a new engine and approval and what not. I didn’t break this engine so don’t laugh in my face. I got frustrated and went to a Toyota dealership and quickly traded that jeep for a 4Runner. Later that day they call me back from Toyota dealership and asked me if there is an engine problem because now there is cel and engine is on its way out. I guess I traded that thing in just in time. I wanted to have a jeep wrangler my whole driving life and look what happened. Laughing in my face that what broke the camels back. It’s a shame.

 

[bill66912]

More resurrection on this thread about spark knock and fuel quality!

I have a 2010 JKU. I bought the truck slightly used with 3k on it in Denver, and drove it back to Detroit.

Since then, I've had to use premium in it where I live to cease the spark knock - especially in summer months.

However, I have gone out of town a few times with the Jeep and have noticed a dramatic difference in mileage and knocking with fuel out of my immediate area in Michigan. Just over the holidays, I was on the west side of Michigan and filled up at a Meijer station with 87 octane and to my surprise, I got 20-21 mpg on the highway going back to the east side of the state! Zero spark knock also. I use Meijer also where I live, because I grocery shop there and get points/discounts that can be used at the fuel station.

I posted a question on another jeep forum, and the consistency answers I received was a different in Ethanol content.
I found a station near me that sells Recreation Fuel at 90 octane, zero Ethanol. I tried it, and sure enough, no spark knock and 20 mpg around town. But at $5/gallon, that isn't a long-term solution.

So in my case at least, Ethanol seems to be the culprit. I've not had this trouble before with other vehicles, even from my BMW motorcycle. But it seems there is a difference in fuel quality and Ethanol content at the Meijer stations around Michigan. Interesting!