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"PINGING"--causes/solutions/prevention?
I have a 1999 Dodge Durango with the 5.2L engine. I've had it into the dealer 3 times because the engine pings. First it was just doing it when I was running around 60 mph, now it's getting worst at lower speeds.
The dealer checked the factory specs and set the computer. They told me that it should be fine. No it didn't fix the problem.
Then the dealer told me that the fuel was causing the proble to increase the octane. I did that and it still pings. Next they tell me it pinging because of my tires. I put a 3 inch suspension lift in the Durango and added bigger tires. I say they are crazy with the tire answer.
I'm taking it back in on Friday, has anyone else had this problem and if so what did you have to do to get rid of it?
I love the Durango, but the pinging has to go.
The dealer checked the factory specs and set the computer. They told me that it should be fine. No it didn't fix the problem.
Then the dealer told me that the fuel was causing the proble to increase the octane. I did that and it still pings. Next they tell me it pinging because of my tires. I put a 3 inch suspension lift in the Durango and added bigger tires. I say they are crazy with the tire answer.
I'm taking it back in on Friday, has anyone else had this problem and if so what did you have to do to get rid of it?
I love the Durango, but the pinging has to go.
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Comments
That has got to be the funniest excuse i have ever heard. Did you laugh at them?
"Pinging" should be correctable. If it gets too bad, it can be very destructive to an engine.
1. Old wires were routed wrong and caused inductive cross fire.
2. Wrong wires replaced with correct wires. Old wires too low in resistance = same problem as 1. caused by too much secondary current.
Harry
Technicians have recommended everything from higher octane fuel (foolish because the ECM won't read the higher octane) to fuel additives (ECM doesn't understand detergent). That tire comment could make sense if they related the extra load the larger diameter places on the drivetrain, but it's still an engine management issue.
No fix that I know of - good luck.
One test to see if the sensor is working is to connect an oscilloscope to the output of the device and with a suitable tool, rap the engine block near the sensor and see what the output voltage of the sensor is. In theory, rapping the engine block while the engine is idling should retard the timing and a change of engine note will be heard - just do not hit the sensor itself ! Regarding larger diameter tires, it's quite possible that the extra torque needed to drive them puts the capture range beyond the capabilities of the sensor control loop.
1.. wires if weak cause fuel not to burn as do plugs.
2.. Oxygenates are added to increase the octane of gasoline and MTBE is the most common. Oxygenates are added to more than 30 percent of the gasoline in the United States, and by the end of this decade, it is estimated that oxygenates will be added to 70 percent of the gasoline. MTBE is being replaced with ethanol. These oxygenates help reduce pinging by creating a better burn. that's why type of gas can be a culprit in this problem. a dead give away is to add an octane boost to your high octane fuel and see how that affects it.
3. timing.. if timing is advaced too much can cause it to fire at the wrong time. one thing with these computer controlled systems is to get a little radical and retard the timming to a high extreme which is more than the computer can compensate for and see if it affects your problem.
4. one other thing that can affect ignition is carbon build up in the cyl. this build up can act like a piece of coal that is extremely hot and can ignite and vapor gases in the engine. alot of times when this is present it tends to allow the engine to run on even after you have turned your key off.
normally #2 or #3 is the problem but any of the above can play a role in it.
wish you luck.
bob in jville.
Lubricant Specialist
http://www.bobistheoilguy.com
Thanks
Al Saadallah
2. ECM flash upgrade is available and generally the first thing a dealer tries because it's quick and easy.
Important to realize:
A. THERE ARE NO KNOCK SENSORS ON THE 5.2/5.9L engines. Don't try to replace them, 'cause they aren't there.
B. BASE TIMING IS NOT ADJUSTABLE ON THESE ENGINES. So, rotating the distributor is not recommended (or possible - I think).
Timing is controlled by (among other things) crank shaft position sensor signals sent to the PCM.
The "big tires" excuse is a joke. A properly tuned engine - even under load - will not ping excessively (at all) at highway speed. It's no different than imposing other loads like trailer towing, or a stiff headwind. Think about it.
Carbon buildup is a possibility. Higher cylinder pressures and hotspots on the cylinder walls could cause pre-ignition. This is unlikely given the age of the vehicle, unless there is an underlying problem to cause excessive buildup of deposits.
Poor grade fuel could cause detonation. However, we're talking Uncle Jesse's Moonshine swill. If you are using major brand gasoline there should be no problem. This engine should not demand premium fuel if properly tuned.
This is a shot in the dark, but perhaps the crankshaft sensor is "overly sensitive." In otherwords, maybe the PCM is receiving a voltage-high signal to allow spark prior to proper crankshaft position. I've not looked at how the sensors are mounted or explored possible manufacturing defects with the sensors to see if this is a possibility.
And finally! I have a 5.9L and experienced "pinging" under load. Re-routing the wires according to the TSB didn't help, but the PCM flash did. Good luck.
I think the 5.2L has been replaced by the 4.7L SOHC V8 (at least in the Durango). The 5.9 is still the towing motor. The 5.9 is admittedly aged, but a workhorse and, in my opinion, bulletproof. Why DC hasn't updated the engine management systems to incorporate proven knock-sensor technology is beyhond me. It just makes sense to get the best fuel economy and power through optimum ignition timing. I've not read specs on the 4.7, but imagine that it is a more up-to-date powerplant.
I just thought of another TSB regarding engine knock on the 5.2/5.9 engines. Apparently there was an intake manifold leak . . . not sure of all the details. It was on some earlier Durangos and Rams. Check it out.
Higher octane fuel ignites at a lower temperature. Hotspots in the combustion chamber, like carbon or an irregularity in the metal surfaces in the engine, can cause premature ignition. Putting the engine under a load and heating up the surfaces of the combustion chamber contributes to the problem.
Premature ignition causes, among other things, carbon build up. More carbon means more pinging. It's a viscious cycle. Once the combustion chamber is "fouled", it doesn't matter what you put in the tank, the engine is going to ping.
I was using the mid-grade and high octane stuff, and my pinging problem was getting worse. Then a wise service writer at the local Ford dealer explained the lower flashpoint issue of high octane fuel to me.
He then outlined the solution to my pinging problem:
-properly tune the engine, making sure all of the sensors are within spec
-clean the combustion chamber agressively (the Ford dealer literally "hosed" the cylinders with cleaner by removing the plugs and fuel injectors and inserting a probe, and added a multi-tank fuel additive to the fuel tank)(change the oil afterwards)
-Buy gas per your car's specifications from high-volume stations (if it calls for 87 oct., that's what it should run on)
-I put a bottle of Techron in the tank about every other oil change (6,000 miles)(the guy at the dealer says every 3,000, but for me 6,000 is working fine)
There are certainly other reasons why an engine would ping. For example, the only time I've had a pinging problem since I made the above discovery is when the thermostat stuck open on one of the cars. The engine was running too cold, which created a different set of problems relative to the engine management system. Changed the thermostat, problem solved.
Don't let a mechanic tell you to try a higher octane fuel unless the car requires for that fuel and you're using something different. Otherwise, the higher octane fuel may in fact contribute to the problem, not solve it.
That is the octane shunt. With it out, the computer manages the engine for 87 octane fuel. With it in, you can use the higher octane fuel and get a little bit better horsepower out of the engine. So says a friend of mine at the local Ford dealer who works as a service advisor. I trust him.
Hope this helps.
Putting 93 octane in a car that requires only 87 won't hurt it - you'll just be throwing money away. By that same token, on today's modern engines with knock sensors, etc., putting 87 octane in one of those engines may just decrease performance.
Lean mixtures can also contribute to higher cylinder temperatures, and thus, spark knock. A faulty O2 sensor, mass-air, MAP sensor, or coolant sensor could cause a spark knock condition. Cold, dense air requires more spark advance, so anything that makes the ECU think that their is colder, denser air in the engine than really is could be a problem. O2 sensor could cause an engine to run lean, but those sensors are generally prone to failure leaving a car running rich.
You might be interested in a Car and Driver article a few months ago (the month escapes me) where different grades of fuel were compared in detail with different engines on dynos and under fairly strict experimental control. It may be englightening.