Engine "pinging"

[Sierra048]

I've been researching the causes to determine what I can do to eliminate, or lessen, the annoying pinging I get when my Jeep goes under a load like going up hill. The Jeep will go over 40K in the next week or so. So far I've replaced the PCV valve and air filter. I don't appear to have any air leaks that would fool with the fuel air mixture. I removed the throttle body and gave it a good cleaning. Today, after doing a Seafoam treatment, I plan on removing the Champion OE plugs and replacing them with some NGK Double Platinums and replacing the spark plug wires with a better grade of wires. I tried a higher octane gas and didn't see any improvement. Has anybody, especially with a Jeep JK, had this problem? If so, were you able to defeat it, or is it something you just live with with a 3.8l Jeep engine? Other than the pinging under load, the engine purrs like a kitten and uses no oil, which is a good thing with these engines per other owners. As a novice, are there any other areas that I could look at?

 

[Doog]

Try a different gas station.

 

[spasm3]

If the egr valve does not open, you could get pinging. The egr cools the combustion temperatures. Not familiar with jeeps, but the egr valve itself, or if there is an electronic solenoid operating it. Techron is a better carbon remover than seafoam.

 

[gathermewool]

It's not under warranty?

 

[TrevorS]

Run Techron / Gumout All In One through a tank, maybe twice.

 

[Chris142]

Try a top end cleaner?

 

[NHGUY]

EGR is either plugged up or the vacuum servo that controls it is bad (very common in Chrysler minivans).

 

[Sierra048]

Originally Posted By: gathermewool
It's not under warranty?


Jeep had a 36 month or 36K warranty. Is the EGR valve covered for a longer interval, like emissions?

 

[Sierra048]

Originally Posted By: NHGUY
EGR is either plugged up or the vacuum servo that controls it is bad (very common in Chrysler minivans).


Is the vacuum servo part of the EGR assembly or a stand alone part.

 

[loyd]

Try a lower gear!

 

[SwampSurvivor]

The 3.8s like to wind up on the JKs. My parents 2008 (complete lemon) wouldn't make any power, and would ping a lot, if you applied much throttle under 3000RPM

 

[Sierra048]

Originally Posted By: Miller88
The 3.8s like to wind up on the JKs. My parents 2008 (complete lemon) wouldn't make any power, and would ping a lot, if you applied much throttle under 3000RPM



Pretty much mine too. Just got finished perusing some Jeep forums and it appears I'm far from being alone. Some claim success by replacing the knock sensor, Seafoam, treating the gas with concentrated Techron, throttle body cleaning etc... IDK. I've got the plugs and new wires so I'm going to go ahead and replace them after seafoaming the engine. I'll pick up a couple bottles of Techron fuel treatment and give that a go. I've already replaced the PCV valve and cleaned the throttle body. If it still persists I'll try replacing the knock sensor since it's easy to do and not really expensive. After that, if it's still there, I'll look next at the EGR system as was mentioned earlier. This seems to be a bigger problem than I realized with the 3.8L. So many people, tried so many different things at once, it's hard to determine what fixed the problem for those claiming success. Thanks for all the input.

 

[MolaKule]

A recap of suggestions so far:

use higher octane gas, clean EGR, check vacuum servo, use lower gear, clean intake system.

You could have carbon in cylinder heads so a good induction system cleaning may be in order.

Do a piston soak if there is carbon buildup on the piston.

Have the timing checked as well.

 

[Sierra048]

MolaKule,

Where would the vacuum servo be located? I asked earlier if it was part of the EGR assembly or a stand alone part. Thanks.

 

[Sierra048]

If I have to go the EGR route, I've seen videos of people removing and cleaning EGR valves with carb cleaner. Has anybody tried, and had success, doing this?

 

[Olas]

Check the cooling system from top to bottom to be sure its not caused by overheating.
Check your spark timing & cam timing.
PEA in the gas.
Whats the static CR?
What octane?
Tell me about throttle position&load&engine speed
5 gas analysis results?
Any info from OBD?

It'll be clear as day when we know those details

 

[Sierra048]

Olas my friend, I have no idea what some of those things are. I've been using 87 octane since the manual claims that's what it needs. I have a scanner and there are absolutely no codes stored or showing. Cooling system appears fine, no overheating. Not a mechanic so I didn't know I could check the timing on this vehicle. "Pinging" most prevalent when rpms drop under load, like climbing a hill. It doesn't "ping" or knock unless it happens as I described above under load at lower rpms. Thanks.

 

[SatinSilver]

www.toptiergas.com, click on retailers and preferably a newer station.

 

[MolaKule]

Originally Posted By: Mfrank84
If I have to go the EGR route, I've seen videos of people removing and cleaning EGR valves with carb cleaner. Has anybody tried, and had success, doing this?


As to your first question I am not familiar engough with that vehicle to comment.

Berryman's or LC20 will decarbon it. Just don't get any cleaner on the diaphram.

 

[tswm]

Originally Posted By: Mfrank84
I've been researching the causes to determine what I can do to eliminate, or lessen, the annoying pinging I get when my Jeep goes under a load like going up hill. The Jeep will go over 40K in the next week or so. So far I've replaced the PCV valve and air filter. I don't appear to have any air leaks that would fool with the fuel air mixture. I removed the throttle body and gave it a good cleaning. Today, after doing a Seafoam treatment, I plan on removing the Champion OE plugs and replacing them with some NGK Double Platinums and replacing the spark plug wires with a better grade of wires. I tried a higher octane gas and didn't see any improvement.


As others have suggested, test whether the EGR system (if equipped) properly function or not. I agree that should be the very first thing to test.

And even though higher octane seemed to not help, for now in an effort to temporarily lessen the symptoms which are especially harmful to the aluminum alloy structure of your motor (gradually but surely), I think it advisable to continue feeding it 91 octane and/or 89 octane, and/or ~50/50 of 87 and 91, for example. You may find that it does not help at all, or sometimes it alleviates and other times no. Of course, not a cure, even if it helps for a while.

Be sure to carefully inspect and for record keeping purposes take photos of your old spark plugs, if you put them back in. If your replace them, do all the research you can to make sure the heat range of the new spark plugs is proper for your vehicle; and label the old spark plugs as to which cylinders they beonged, respectively. If original spark plugs are found to be in spent condition (though a low mileage vehicle), such as too wide a gap, and for probably other reasons (and check for the color of each as well as for too wide a gap prematurely induced possibly by antifreeze from out of blown head gasket), and/or somehow not being of the proper heat range speced by the OEM, such spark plug ills may be one of the many causes for engine pinging.

In addition to inspecting the appearance of old spark plugs, I think it advisable to have the cooling system pressure tested for the possibility of blown head gasket. Which condition will in many cases be found to be the real cause of an engine pinging under load.

And also, you may need to draw off a small sample of oil and obtain a UOA.