Why does a 2000 ford ranger 2.5L ping under acceleration?

Answer 1

Pinging can be caused by using too low an octane fuel, but in your case this engine only requires 87 octane so as long as you are using a quality fuel that should not be an issue. Many things can cause pinging, but let's start with the obvious. Your Ranger is 8 years old. Check/replace the spark plug wires. Even on engines with few miles, many have experienced pinging problems caused by bad spark plug wires. One cylinder (maybe more) would misfire, causing the ECM to detect a rich condition, and lean out the mixture to the other cylinders, causing the engine to ping. Look for open wires, intermittent wires, and leaking wires (look for leaky wires on a dark, damp night). Check the intake manifold to block gaskets for leaks. If this gasket is leaking, it can cause the engine to ping. If you run a cylinder compression test and find one or more cylinders that measure higher than 170-180 psi, there is a good chance that it will ping on anything less than high octane gasoline, which your vehicle should not need. A build up of carbon deposits on the piston tops (from engine oil leaking through an intake valve stem seal or intake manifold gasket) is the most common cause of high compression readings from one/two cylinders. For engines with carbon buildup or persistent part throttle ping, run through three treatments of Techron or Seafoam. Let your gas tank get down to one quarter full and add a $7 bottle of Chevron Techron or a $6 can of Seafoam. Run this down to empty. Then add 12 gallons more gasoline and add another treatment. Run this to almost empty, add 12 more gallons plus a third treatment. This will cost you $18-$21. What this will do is clean out carbon deposits out of your combustion chambers and lower your compression ratio back to the factory number it had when the cylinder was clean shiny metal. It is a cheap thing to do and I almost guarantee it will lessen the pinging if it is caused by carbon buildup. Carbon deposits not only raise compression - it also insulates the cylinder head and prevents good cooling from above. The Techron/Seafoam may also clean out a partially plugged fuel injector that is causing one cylinder to run leaner than the other seven. This is the same problem as the low fuel pressure but is confined to one cylinder. There is no guarantee that a treatment will completely eliminate the pinging. Gasoline engines run an aggressive spark advance curve and rely on EGR to prevent engine ping. If the EGR valve has clogged or stuck (or been blocked by those seeking to improve mileage), the quick advance curve will cause the engine to ping. If all else has failed, verify that the EGR circuit is functioning properly.