mike2711@yahoo.com

I have a 1999 Ford Ranger 2.5 with 55k miles that pings under load. It
started all of the sudden with a new tank of gas about 3 tank fulls
ago. I have always run middle grade (89) with no problems. At first I
thought it was a bad tank of gas, but has persisted with fresh fill
ups. It idles a little rougher when cold and hesitates some but when
warmed up, seems ok. It may seem strange but when I drive to work in
morning, it rarely pings. When I drive home (same route) in the late
afternoon, it pings persistently. Weather related? (Colder air in
morning, warmer in afternoon!) The check engine light has not come
on... If the check engine has NOT come on, does that mean all sensors
are working? I am currently running a can of Berryman B12 with premium
gas as an initial inexpensive try to remedy. Anybody have any ideas?

JimV

Get the error codes read. A failed knock sensor will cause this and will
not turn on the CEL.

mike2711@yahoo.com

Hi Jim V! Thanks for the response. I was told by dealer and Autozone
that if the "check engine light" doesn't come on, it won't record any
codes?? I also forgot to mention that the truck has a new "mass air
flow" sensor about 6 months ago. I already tried cleaning the maf
filament wires with contact cleaner.

JimV

They are wrong. Some codes are just recorded including the knock sensor.

Steve

Many times the code gets logged in, but because it doesn't meet x-criteria,
no CEL (Check Engine Light) Some codes require 2 or 3 times of certain
conditions to set the light, until then they can be listed under "pending
codes" in many scan tools




--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Undercar Specialist

mike2711@yahoo.com

Thanks Stephen! Typically will dealerships scan the codes for free or
do they charge? Will they even do it without the CEL on? Autozone won't
scan codes unless CEL is on!

JimV

Dealers don't to anything for free. Tell autozone it's been coming on
intermittantly. They'll read it.

R&B

I read something about cleaning the wire in the mass airflow sensor that was
supposed to stop the pinging. However, if you drive it long enough while
pinging, engine damage will occur. It happened to me with my Ranger with a
3.0 V-6. I put larger tires on the truck and it started pinging. I presume
it was the extra load on the engine due to the taller tires effecting the
overall gear ratio. I noticed the coolant had turned brown. I drained it,
flushed the radiator, then about 4 months later it was brown again.
Combustion gases were getting in the coolant. The pinging (preignition)
probably cracked the head or took the head gasket out.
Ron

mike2711@yahoo.com

Thanks for the replies! I have cleaned the MAF sensor, in fact the
sensor itself is only a few months old. I took the truck to a local
auto parts store to scan the trouble codes. There were none! Am I to
assume that all the sensors are working properly? Is it possible that
it just simply needs a tune up. It isn't scheduled to have one till
100k and it only has 55k.

Steve

Pinging is pre ignition. Something is starting the combustion burn before is
suppose to. Sometimes it is caused by carbon build-up in the combustion
chamber, a run-rite fuel tune is suppose to burn out the carbon.
http://www.run-rite.com/industry/products01a.htm We sell it at our
store, and I do believe it helps. I would start with a good tune up, and go
from there..



--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Undercar Specialist