LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

pinging
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=42290		 Page 1 of 1
Author:  libbygreen [ Wed Apr 15, 2009 9:58 pm ]
Post subject:  pinging
Just wondering if anyone else has ever had this. my 2007 with the 3.7 automatic has a frequent ping upon acceleration. Not heavy acceleration. Mostly like when you are turning a corner and just start to press on the gas pedal. It's a rattling sound just like when my old taurus needed higher octane fuel. It doesn't do it under load, never when I am going up a steep hill or any harder acceleration.
I have had it in to 2 Jeep dealerships numerous times. They have ridden with me and heard it, they have had their diagnostic machines hooked up while we were moving. They "de-carboned" it. changed the plugs. No one can tell me what it is. It is more noticeable in warmer weather. I dont know if its because I live in Wisconsin and my windows are never down in winter or what, but its getting nice again and once again its noticeable.
Anyone experience this? Any ideas?
Author:  tjkj2002 [ Wed Apr 15, 2009 10:09 pm ]
Post subject: 
Run higher octane gas.I have to run premium(at least 90 octane) to keep mine from pinging/knocking.
Author:  ATXKJ [ Thu Apr 16, 2009 2:45 am ]
Post subject: 
the knock sensor should detect and retart the timing
the sensor may be having problems.

(I had that on an Explorer - I haven't driven a Gas Liberty)
Author:  libbygreen [ Thu Apr 16, 2009 3:25 pm ]
Post subject: 
Will try the higher octane. I did once before but it was only 89. As far as the sensor, the 2 dealers have gone over it thoroughly.
Author:  SavageUrge [ Thu Apr 16, 2009 3:53 pm ]
Post subject: 
You can try the higher octane gas, however that is not a permanent solution. It is only a mask. My '99 Dodge Ram 318ci did that. I was told that it could possibly be a condition called pre-ignition. This is when the temperature in the cylinders is so high that the fuel/air mixture ignites prior to the spark plug firing. This condition could lead to an exploded piston because esentially you're getting a "double-tap" ignition condition. Once when the piston reaches the top of it's travel and again when it is on it's way down or traveling back up. Obviously, it's a serious condition that should be checked out immediately prior to any permanent damage occuring.
Author:  Jeepjeepster [ Thu Apr 16, 2009 4:05 pm ]
Post subject: 
SavageUrge wrote:
You can try the higher octane gas, however that is not a permanent solution. It is only a mask. My '99 Dodge Ram 318ci did that. I was told that it could possibly be a condition called pre-ignition. This is when the temperature in the cylinders is so high that the fuel/air mixture ignites prior to the spark plug firing. This condition could lead to an exploded piston because esentially you're getting a "double-tap" ignition condition. Once when the piston reaches the top of it's travel and again when it is on it's way down or traveling back up. Obviously, it's a serious condition that should be checked out immediately prior to any permanent damage occuring.


AKA, pinging. :)

And yes, using a higher octane is a permanent solution. Its the whole reason why we have have the option of using higher octane at the pumps.

Ive never heard pinging with my 3.7. I can hear it in our I-6 engines sometimes but Ive not heard it in along time.
Author:  JeepinJarhead03 [ Thu Apr 16, 2009 4:25 pm ]
Post subject: 
the 4.0 I6 has a 8:8 my 03 3.7 has a 9:1 i believe (newer is 9.7 don't know what year this changed)


the reason we have octane differences in the first place is because different engines have different compression

higher compression engines require higher octane to prevent predetonation due to compression

it's the exact basic principle that DIESEL engines operate on

diesel is like 50-60 somethin octane and they operate without spark plugs

you can retard the timing all you want and compression will still cause a degree of detonation due to compression

the sensors and timing changes only assist in masking it

I've had some pinging with my 3.7 with 87 if i use certain brands of gas but again the differences in the heads on the two engines plus the auto timing is masking symptoms, on the other hand my friends 4.0 I6 with a lower compression ratio runs like absolute poo on 87, we have to run 89 or higher

yes they will run with the lower octane and you may not even notice it
but it's not exactly a good thing for the engine, nor is it good for the engines performance or efficiency but there is a point where the octane level exceeds the engines requirement and that's when it becomes wasteful to your pocket
Author:  libbygreen [ Thu Apr 16, 2009 4:31 pm ]
Post subject: 
Savageurge,
It has been checked out many times by 2 seperate Jeep dealers. No one can figure out why its doing it. One dealer told me not to worry about it. You really have to be listening for it in order to hear it. But I hear it and it bothers me.
Author:  ribbon [ Thu Apr 16, 2009 4:33 pm ]
Post subject: 
Diesel = 15-25octane
Author:  JeepinJarhead03 [ Thu Apr 16, 2009 4:58 pm ]
Post subject: 
thanks for that clarification and correction:

what the hell was the 60 somethin octane stuff i've seen at the pumps? :lol:
Author:  SavageUrge [ Thu Apr 16, 2009 9:44 pm ]
Post subject: 
The 3.7L is designed to run on 87 octane gas. If you NEED to run higher octane to prevent "pinging" then there is something wrong with the engine. It could be anything from weak valve springs to a bad timing chain sensor. The reason the technicians can't find anything wrong is becasue all they do is hook it up to a machine that they rely on to tell them what is wrong. You need to find a good true mechanic that knows how to listen to an engine and "hear what it's saying". How many "technicians" use stethoscopes these days?
Author:  tjkj2002 [ Thu Apr 16, 2009 10:07 pm ]
Post subject: 
SavageUrge wrote:
The 3.7L is designed to run on 87 octane gas. If you NEED to run higher octane to prevent "pinging" then there is something wrong with the engine. It could be anything from weak valve springs to a bad timing chain sensor. The reason the technicians can't find anything wrong is becasue all they do is hook it up to a machine that they rely on to tell them what is wrong. You need to find a good true mechanic that knows how to listen to an engine and "hear what it's saying". How many "technicians" use stethoscopes these days?
I'm chipped,reason for my need for higher octane.


Oh and I always use a stethoscope,partially why I'm almost legally deaf.
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/