Jeep: Pinging Jeep

Runk wrote: 

There is a lot of debate on this but the simple fact is because 87 IS
NOT enough octane for you engine under a heavy load plain and simple.
YOu are hearing knock because it is exceeding your ECM's abilty to
control. Know this, whenever you ECM retards spark to control ping you
are lossing power and MPG and repeated knocking under heavy loads is
hard on valves too. 87 was designed for 8 to 1 compression engines and
the ONLY reson their is a sprak knock detector is to limit consumer
complaints about not being able to run the cheapest possible gas even
though you are limiting power and MPG (especailly on hot days becuase
octane requirement increase with tempature). Myself I do not use 87 in
anything except my old tractor and mower and a 79 Jeep with 8 to 1
compression. Everything else is 89 or better. I justm finished hauling a
13,000 lb trailer 26 miles one way twice with my 2000 K3500 5.7 powered
truck this weekend and it did so without a fuss and pulled better than I
though it would and would cruise 65 with little effort. I run 93 in it
though sometimes I top it off with 89.

-----------------
www.thesnoman.com

Runk proclaimed:
 
If you still have your owner's manual, it should tell you that if you
are pulling a heavy load, you should move up a
grade or two in fuel, particularly in hilly or hot areas. Surprised
you don't get pings on regular. I live at sea level and ever since
the gas formulation changed a coupla years ago, I get mild pinging
on anything lower than midgrade.

Hi,
I have a 2004 Jeep Wrangler with the 4 liter and it pings even when I'm not
pulling anything and using mid-range gas (88 octane). I've had it in twice,
had the ECM re-flashed and it still does it. My friend with a 2001
Wrangler, same engine, does not have this problem even running 86 octane.
I'm stumped.


"Lon" <net> wrote in message
news:com... 

John Smith wrote: 


Use better fuel because if you have ECM reflashed to retard spark more
to be able to use low octane fuel, it will make less power and get
poorer MPG too.

--

-----------------
www.thesnoman.com

Maybe some more info ... like trailer weight, transmission, rear end ...
maybe that trailer's too much for the jeep. E.g ... swapping out the rear
end for something more suitable for towing might be the solution if you tow
a lot. If you have an auto with overdrive, maybe don't use it when towing.
Or maybe if you don't tow that much, just do what yer doing ... use premium
when towing.

"Runk" <R.Runkle(nospam)@mchsi.com> wrote in message
news:14k0f.388885$.. 
regular 
but 

Bowgus wrote: 


87 is really not enough octane for most V8 but some people are stubborn
and try to hang on to it. I reminds me of when I was a kid and they had
regular and super leaded and car came from factory with 10.5 or 11 to
one compression and some people were too cheap to put super in them and
you could here them knock everytime they pulled away from a light or a
stop and sometimes passing you too.

--

-----------------
www.thesnoman.com

"Runk" stated he has the 4.0L ... that's a straight 6 ... not a V8.
 

Still applies. 9 or 9.5 to 1 compression is too much for 87 with a load
or a warm day with A/C on I do not use 87 in any of my fuel injected
vehicles and have not for years. I have a 89 burb that wanted to knock
on 87 at times when I got it new even with knock sensor (it could not
retard spark enough) and performance and MPG was not good. I use 89 in
winter in it and 93 in warmer months and it has not knocked for years
and it has gotten as high as 19 mpg on hiway trips too and still runs
like a top.

Bowgus wrote: 


--

-----------------
www.thesnoman.com