2022 Gladiator (3.6ltr V6 GPEC 2) pinging at very low throttle settings

[adamjedgar]

Hi guys,
I have a Jeep Gladiator with 3.6 litre v6 engine that is pinging at very low throttle settings...approx 2,000 rpm whilst just barely touching throttle (just enough to maintain speed at about 60km/hr on flat ground).

It started doing this straight after its first 12k service.

The jeep dealership who serviced the vehicle have said they did nothing to the car, so it isn't anything they have done and apparently the computer is not producing any error codes ( i suspect that may be because its such low throttle settings that its pinging?)

When driving around in traffic on the streets, its pinging almost all the time...just barely audible, but there nevertheless.

I have a full fuel purchase history for this car (i use it for business so i have all the fuel receipts for every tank of fuel its ever had). It has almost always only had 98 octane fuel...a couple of times 95 octane when i haven't been able to get 98.

Car is running 33" tyres with a 2" lift.
I have never had anything done to the motor...its stock and only touched once by jeep (ie first service check)

I found the following re engine knocking...

There are many reasons, due to which knocking occurs in an SI engine. These are:​

1. High compression ratio: Due to high compression ratio, sometimes a secondary flame front is formed starting from piston head or any other hot spot if present, which collides with the flame front generated by the spark plug. In short due high compression ratio, preignition takes place leading to knocking issues. ​

It can be resolved by reducing the compression ratio if a VCR(variable compression ratio) system is used.​

2. Due to the presence of a secondary hot spot: Due to long hours of running the engine, unburnt/partially burnt carbon particles get deposited on the piston head, screw threads, regions around the valves, etc. These deposited carbon particles act as ignition source when the compressed fuel-air mixture is on the verge of burning (no spark, primary flame front not yet started). Thus before the actual start of the primary flame front, a secondary flame front starts travelling in an opposite direction, cause a collision and hence knocking. ​

it can be resolved by cleaning the engine cylinder(s) and all the carbon deposits must be surely removed. ​

3. Due to the overheating of the engine: In the case of SI engines, if the heat of combustion chamber is not efficiently dissipated, then there is a significant rise in the temperatures of the combustion chamber parts such as piston head, valve heads, spark plug and threads of spark plugs screw and other similar parts. Due to this rise in temperature, these all overheated parts act as ignition sources and start multiple flame fronts, which collide and cause knocking.​

It can be fixed by fixing/improving/modifying the engines cooling system and use coolent if possible.​

4. Due to the low speed of engine: Due to low engine speed, there is a sufficient ignition lag, which gives enough time for a secondary flame front to get formed leading to the knocking.​

If the speed of the engine is increased sufficiently, this issue can be resolved. Another alternative can be "advancing the spark timing". This will reduce the ignition lag and hence the knocking.​

5. Knocking characteristics of the fuel: The fuel to be used in the engine should be tested for it knocking characteristics (octane rating) in a standard engine setup and a good quality antiknocking fuel should be used in order to get rid of this issue.​

Has anyone experienced this kind of pinging with the late model 3.6litre engines? I have heard they run a higher compression in the late model pentastar engines (11.5 : 1) is it possible that this has something to do with it?

I am considering just taking it to a performance shop who have the right equipment to dyno the car and check its fuel/air settings at different throttle settings.

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[@californiajeeping]

Very common. Probably has an issue with the camshafts.

 

[Skull]

98 octane? Or even 95….vehicle does not require or need that. I have had slight pinging on both my gladiators at light throttle in higher gears especially uphill.

 

[adamjedgar]

the jeep dealership where i first purchased it spent time on the car, however, they cannot figure it out.
apparently the answer is, "it is not throwing any error codes so nothing is wrong with it"

 

[Labswine]

98 octane? Or even 95….vehicle does not require or need that. I have had slight pinging on both my gladiators at light throttle in higher gears especially uphill.

He's down under...octane definitions are different there than here. He'd also posted this on the Jeep Forum board. I had responded as well with the 'that's way too high octane and you don't need it...' and was corrected. If I recall, their 98 is equal to our plus of 89 octane and, their 95 is our 87 regular.

 

[adamjedgar]

He's down under...octane definitions are different there than here. He'd also posted this on the Jeep Forum board. I had responded as well with the 'that's way too high octane and you don't need it...' and was corrected. If I recall, their 98 is equal to our plus of 89 octane and, their 95 is our 87 regular.

He's down under...octane definitions are different there than here. He'd also posted this on the Jeep Forum board. I had responded as well with the 'that's way too high octane and you don't need it...' and was corrected. If I recall, their 98 is equal to our plus of 89 octane and, their 95 is our 87 regular.

thats correct, Australia follows the European method for calculating Octane Rating. The US and Canada use a different model.

 

[adamjedgar]

back to my original problem...
Jeep had the car for 2 days...they deny they can find anything wrong with the engine. The mechanic who i took for a drive who heard the noise whilst i was in the car with him, has since told the service manager he cannot hear any pinging noise.
They say the computer is not throwing any error codes, however, i have since put more than 2 tanks of fuel through the car and it pings just the same as before.

Conditions for pinging...

about 2000rpm almost coasting down the road at about 60km/hr.

It will keep pinging until i change throttle setting or speed.

something is definately not right as the car did not do this prior to the first 12k service...it started immediately after that service (As did the transmission weirdness...almost as if it is slipping a bit in second gear)

so does anyone have any ideas on how i can prove to jeep that there is something wrong with the engine or fuel management system?

coud a dyno test with exhaust gas sensor attached help with pinging? What tests would a mechanic normally do on modern cars to isolate the cause of pinging?

 

[Andy29847]

My Jeep does (2020) this too. I think it is called pre-detonation, and it is due to carbon build up. The design of the PVC valve can contribute to the condition because they pass more oil than other PVC valves.

I run regular gas. I drive my Jeep like a little old man. I watch my fuel mileage gauge more than any other gauge. These kind of driving habits contribute to carbon build up. Last week, I pumped in some high octane fuel, dumped in a bottle of Chevron Techron fuel additive, and drove it like I stole it for a couple of hours. The knock is all but gone. I'm satisfied it will be gone by the time I need gas again. BTW, the "drove like you stole it" used to be called the "Italian tune-up."

 

[adamjedgar]

I have an update on my issue...Jeep dealer has sent an email to Jeep Australia asking for one of their technicians to come and look at my car.

I am not sure whether or not this will be of any use, however, perhaps it might produce a favourable outcome.

To be honest, my gut tells me that the only real option is to first obtain a professional diagnosis from a performance dyno tune specialist. They will be able to simulate the exact conditions where the vehicle is pinging (1500-1800 rpm with just a little throttle acceleration) and take some dyno readings from exhaust monitoring sensors etc and from that i should be able to then go back to Jeep with specific information about what is actually causing the pinging at this rpm and torque setting.

What i can say is that it is doing this all the time now...i can reproduce the ping driving around town at low speed any time.

also, in the last 3 weeks, the jeep fuel economy has climbed from 13 ltr per 100km to 15 ltr per 100km, and given i use the vehicle for work and regularly work in the same locations (mostly shopping centres around Melbourne), the economy should not change...so something is definitely wrong.

 

[adamjedgar]

Hi Guys,
I have an update on this issue...see Service Report extract from Jeep Australia Technician below

I am deeply concerned about the finding of oil on top of cylinder 3 piston and am wondering why small quantity of carbon has been found deposited on cylinders 1,3,5 and yet no mention of the opposing cylinder bank (ie 2,4,6)?

 

[Hootbro]

I am deeply concerned about the finding of oil on top of cylinder 3 piston and am wondering why small quantity of carbon has been found deposited on cylinders 1,3,5 and yet no mention of the opposing cylinder bank (ie 2,4,6)?

Cylinders 2, 4 & 6 are the left side bank. That requires removing the upper plastic intake for spark plug access and I do not see that mentioned on the repair order even though they mention treating "all cylinders" but that just maybe word play and they only treated the right side bank as that is more easily accessible without taking the upper intake off.

 

[adamjedgar]

just thought i would post an update...I am still waiting for Jeep to get parts to fix this issue and there is no ETA date on when that is going to happen!

Just to recap, this problem first arose when the car had 12,000km on it. The odometer is currently sitting on 34,500km...so ive done 22,500 km since the problem started and i reckon by the time it gets fixed, the damage the consistent pinging, when at/or passing through 1800-2000rpm, is doing to the motor will have already been done!

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