johanswift

I have recently noticed frequent pinging/knocking from the engine on hotter days whilst engine is under load (2000-3000 rpm mostly). This only started happening from 26,000 km and never used to be present before. I have done approx 31,000 km now.

My question is: Could this be a sign of spark plug wear? I have also noticed a slight rough idle lately, although the rpm needle still remains steady at around 700rpm. I doubt whether this has to do with bad fuel, as this now happens more frequently, no matter where I fill up.

Please advise.

jkkat

Tried super unleaded fuel???
Spark plugs and wires should be replaced @ 30,000 miles.

simon

Did you use the correct oil filter? Some people on here were using the wrong filter which made the engine ping/knock.

Hkx3

What is this about an incorrect filter? I use the mopar filter, and hear the tick from time to time, under load, and when the engine is fully warmed (like after a two hour drive)

aldaman

Had that same issue cruising with the RPM under 1500....Switched to 92 octane and seems to work...You should give that a try first

downunderdave

Yep, mine was pinging a fair bit driving it on the beach this week-end. Reckon the fuel was crap.

johanswift

I hear your comments on fuel quality. Here in South Africa we basically have a choice between either 93 or 97 unleaded. Ever since I bought the JK, I was doing fine on 93 with no pinging - until about 26k. It is only lately that I have been experiencing this problem. I'll be checking the plug gaps this weekend - could be one or two out of spec, causing the pinging. I believe the bigger the gap, the more "advanced" the timing becomes, therefore increasing the possibility for pinging in one or more cylinders.

As for comments on using the wrong oil filter, I personally don't think it is related to the actual ignition pinging sound. It might affect the actual "valve train tick" if it somehow limits or changes the oil flow through the engine. But I'm not referring to this specific noise/problem.

The rough idle I'm currently experiencing strengthens the case for faulty plugs. I will check and report back soon.https://www.jk-forum.com/forums/imag...s/thinking.gif

ronjenx

True "pinging" is caused by preignition, but I have never heard of what you said about the gaps being too big. Early spark isn't always the cause of preignition.

wilywillie

I usually use cheapo fuel (Citgo, Wawa), and hate the idea of spending even MORE on gasoline!! 87octane works for me, knock on wood....
For rough idle, I've (on other vehicles) always put in a jar or two of injector cleaner (STP) when the fuel level is low.(makes mixture richer) It's basically super high octane fuel (JP for you Navy guys), and it always did the trick

johanswift

Ok, checked all the plugs - they seem fine. I think the pinging started when they reprogrammed the Engine control unit during my 24k service. Still, I would have thought that a knock sensor would prevent the ping. Not sure the 3.8 is fitted with one though..