I have a 92 explorer, the problem started at about 130k miles. Had ping when going up hills or towing. Problem kept getting worse and louder.
I ended up getting a new engine because the valves apparently blew up, got to hot and three of the valves had a bite out of them. pretty much ruined the engine, so replaced it.
Engine ran good for about 2 weeks, then started pinging again, now it is pinging again pretty bad. the engine is two months old.
there are no codes on the EEEC.
any suggestions would be appreciated

 

pinging seems to be common complaint with the 4.0 OHV engine. It's can be caused by carbon build up in the cylinders (doesn't seem likely with a new engine. Was it a new engine or a good used one?) If that's not the case it's usually caused by the engine running a little lean. This can be caused by a dirty mass air flow sensor, or a vacuum leak. The lower intake bolts like to come loose and cause a leak there.

 

this is a rebuilt engine from napa, will try to clean the MAF sensor. thanks

 

There is a TSB out on detonation for the 4.0L engine. It describes how to de-carbon the engine. I posted it in the Ranger forum in early to mid Feb; you may want to have a look at it. Also, another FTE fan has had results using marvel mystery oil; that was posted in the Ranger forum a little over a week ago.

The comment about the MAF sensor being dirty and loose intake bolts are also valid points and can be easily addressed. The TSB is pretty simple to implement too.

 

You may want to try running with a colder spark plug, as a plug that is too hot can cause pre-detonation because it is burning too hot and the plug will actually start to glow and cause the gas to burn before the plug actually sparks. You would typically run a colder plug for driving longer distances, lots of freeway driving etc. The drawback is that a colder plug will typlcally foul out faster as it is not hot enough to burn off carbon deposits.

*****Here is a little blurb from Edelbrocks website on Spark plug heat range selection.******

http://www.edelbrock.com/automotive/sparkplugs.html

The term "heat range" refers to the relative temperature of the core nose of a spark plug. The words "hot" or "cold," when used in referencing spark plugs, are often a source of confusion and misunderstanding, since normally a hot spark plug is used in a cold engine (low horsepower) and a cold plug in a hot engine (high horsepower). The terms actually refer to the heat rating or thermal characteristics of the plug; more specifically, the plug's ability to dissipate heat from its firing end into the engine cooling system. A cold plug transfers heat rapidly away from its firing end into the cooling system and is used to avoid core nose heat saturation where combustion chamber or cylinder head temperatures are relatively high. A hot spark plug has a much slower rate of heat transfer and is used to avoid fouling where combustion chamber or cylinder head temperatures are relatively low. The primary means of adjusting heat range are by varying the length of the core nose and the alloy material used in the electrodes. Hot plugs have a relatively long insulator nose with a long heat transfer path. Cold plugs have a much shorter insulator nose and thus, transfer heat more rapidly. The heat range of a plug does not affect the power output of an engine. Rather, it allows the plug to function as designed for the duration of the racing event. In other words, once the correct heat range is found that prevents fouling and does not contribute to the pre-ignition or detonation, a change to a hotter or colder plug will not have a positive effect on engine performance.