Sponsored

Back again with a new Issue, Spark Knock??.... any Help?

ShadowsPapa

Well-Known Member
First Name
Bill
Joined
Oct 12, 2019
Threads
247
Messages
40,440
Reaction score
53,853
Location
Runnells, Iowa
Vehicle(s)
'25 JTMX, '23 JLU 4xe, '82 SX4, '73 Javelin
Occupation
Retired auto mechanic, frmr gov't ntwrk security admin
Vehicle Showcase
3
My 2022 Mojave has had an itermittent spark knock from new. Very short duration until recently. Over the past month (doors off, so it could have been happening a bit longer) the spark knock duration has gotten longer, always hot, always a slow accelleration often during an upshift (automatic). Yesterday I could feel a power drop while going uphill which stopped the knock. Am I correct in assuming the engine sensed the knock and reduced power? It didn't throw a code.
I'm trying to gather as much information as possible and/or fix myself because the dealer will say this is normal.
No, it senses the knock before you can even hear it and adjusts the timing and mixture as needed. It doesn't "reduce power".
Did it shift during that time? that may be what you felt. You will not feel the subtle adjustments the PCM makes to stop detonation.
Do you baby it? Do you keep a light foot on the pedal instead of giving it the throttle needed to make the hill? The fact that it upshifted going up a hill makes me ask.
TRUE detonation is RARE in these. They have sensors that know when it happens before you do. Most of what people here are ordinary engine sounds or rattles from shields, exhaust and so on.

(I have no idea why people call it spark knock as it has zip to do with a spark. Must be some magazine writer or marketing company made that one up)
Sponsored

 

zprovo

Well-Known Member
Joined
Dec 9, 2019
Threads
5
Messages
136
Reaction score
108
Location
nashville, tn
Vehicle(s)
Gladiator BMW-R1150GS Toyota-FJ60 Porsche-914
Occupation
Architect
I think I have babied this car some. It's the first automatic I have owned, so that may be part of it (since I'm not quite as engaged as I might be). It currently has 74k miles on it.
Maybe it needs an italian tune up? There's probably some Fiat DNA buried in there somewhere.

It didn't shift when I felt the "reduction in power" it held 3rd all the way up the hill. I'm super sensitive to how this car shifts. It will often "hiccup" between 3rd and 4th so I usually know where it is.

I call it spark knock because that's what Stellantis calls it. Back in the day I would say my engine was "pinging". I have two older cars that I can set the timing on and if they ping I tend to assume that I got the timing wrong (too far advanced) or I got cheap gas, or both.
I get the need for precision, I really do. My need for precise language drives my wife insane. That said, I think we can assume knock, spark knock, detonation and pinging mean roughly the same thing regardless of actual semantics.
The sound coming from my Jeep sounds very similar to typical engine ping and I can modulate it with my right foot.
 
 







Top