2002 Ford Explorer - Engine pinging (predetonation)

:confused:

I own a 2002 Ford Explorer with over 100K miles on it. Over time, the engine has started pinging and has become more noticable over time. The local Ford dealership said they could not find any codes, and that there was no knock sensor. They also said they called Ford Technical Assistance and did not receive any additional information from them. In the mean time, the pinging is becoming more noticable.

Does anyone have any experience with this?

Aloha~
Try switching to a higher octane fuel like 89 or 92. Cars with high mileage tend to exhibit knocking and pinging and sometimes can be remedied by switching to higher octane.

Larry =)

Mobil 1 oil when you get your oil changed adn high octane.
Ford suck I have a 1997 Explorer and I have 105k miles and I'm having tranny problems it sucks I have spent liek $1200 to get the god damn O/D light to stop flashing!
It still flashes so I just took out the damn bulb.

I have the same problem. I tried switching Octane and it didn't work....Could the EGR valve cause this problem ?

Pascal

Here's the answer to my question about the EGR valve.

Exhaust Gas Recirculating Valves
What are they? What do they do? How do they fail??
EGR Valves have been around for a long time. Way back in 1972 GM used them in an attempt to reduce emissions of oxides of nitrogen (NOx) which were a major cause of air pollution, mainly photochemical smog, that kind of smog which is formed when strong sunlight shines down on the exhaust gasses we puke out of our tailpipes by the billions of cubic feet a day.

A short chemistry lesson is in order here. It was discovered way back when, that high combustion chamber peak temperatures (the really short duration high temperatures near the end of the combustion process) caused oxygen and nitrogen to combine chemically and form these oxides of nitrogen mentioned above. Most of the anti-pollution devices of the day did a pretty good job of reducing the other bad by-products of combustion, namely excessive hydrocarbons and carbon monoxide, however they tended to induce the formation of oxides of nitrogen. Something had to be done else we would all die of smog diseases.

The automotive engineers figured that they needed to do something to lower the peak combustion temperatures which only occurred under certain high load driving conditions. They figured they could do so at the expense of power and fuel economy but what the heck, ya can't have everything! If they could only add something to the combustion chamber that would act like sort of a fire extinguisher to cool the combustion temperatures that would do it.

So they invented a way to allow some very inert gas to get back into the combustion chamber only when needed. They needed a source of this gas - it wasn't air, cuz that contains oxygen and nitrogen which caused the problem in the first place. So they chose carbon dioxide. Where to get a supply of carbon dioxide . . . ??? Hmmmm, how about the exhaust system? That is mainly carbon dioxide and water (plus a zillion other noxious chemicals) Suppose we allow some of the exhaust gas to get back into the intake manifold under strict control and only when we need it? That would cool the combustion chamber and prevent the formation of the NoX. Maybe we should call it recirculated exhaust gas (REG??). But a guy named Reginald voted no cuz he didn't want his name associated with a car part, so they called it exhaust gas recirculation (EGR) since there was nobody around with that name.

Now we understand why it is there. And we understand what it does. So what can go wrong with it and what are the symptoms??

It's really pretty simple - it can be open when it isn't supposed to be, or it can be closed when it is supposed to be open. Not rocket science, but it is science. If it is open when it is not supposed to be open, at idle for instance, It will act like one monster vacuum leak and the engine will not idle or will idle really roughly. If it doesn't open when it is supposed to open you will probably experience a symptom of "pinging" or "knocking" since the combustion chamber temperature will be higher than normal (one of the main causes of pinging in an engine).

There are a zillion different types of EGR valves some of which work strictly on vacuum, and some which work on a combination of vacuum and pressure. Some have electronic controls, some have mechanical controls. I won't go into detail here about all the different types but suffice it to say that most can be checked by looking inside to see if the plunger shaft is stuck open or doesn't move when the engine is revved up (after it is warmed up). Replacement is probably the easiest part since most are held in by two small bolts and have a vacuum line connected to it. The hard part is whipping out your Visa card to pay for it since most of them will drain your reserves in a hurry!!

How old are your spark plugs??? I recently had minor pinging on my Chevy truck w/ 80K miles and decided to go ahead and replace the plugs. They are supposed to be 100K mile platinum plugs but obviously they don't last that long since changing them resolved my pinging and increased my gas mileage by 2 mpg. I'm guessing that sometime between 50-60K miles they were bad since that's when my mileage decreased.

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Originally Posted by Long Distance Voyager

:confused:

I own a 2002 Ford Explorer with over 100K miles on it. Over time, the engine has started pinging and has become more noticable over time. The local Ford dealership said they could not find any codes, and that there was no knock sensor. They also said they called Ford Technical Assistance and did not receive any additional information from them. In the mean time, the pinging is becoming more noticable.

Does anyone have any experience with this?

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Well, I replaced the plugs and I can still hear the engine pings. :(
My neihbor ( who's a mechanic by trade) put OBDII to check the EGR and Pressure sensor and could not see anything wrong with the engine.

Suggestions anyone ? Should I replace the pressure sensor or the EGR on specs ?

Which one did you replace? Did it remedy the problem? I have had the same problem for a while with my lincoln LS 2001.

Does anyone out there have any solutions?

If the "pinging" is between 2000 & 3000 rpm and you have a 4.0L motor, the problem is probably a loose timing chain. There is a Ford service bulletin on bad timing chain guides and/or tensioner. I tried higher octane gas until I figured this out. I have gotten mixed reports on the need to repair this. My local mechanic thinks their is no danger of it breaking or slipping so leave it alone but he did quote $300-$400 to fix it.

Quote:

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Originally Posted by Long Distance Voyager

:confused:

I own a 2002 Ford Explorer with over 100K miles on it. Over time, the engine has started pinging and has become more noticable over time. The local Ford dealership said they could not find any codes, and that there was no knock sensor. They also said they called Ford Technical Assistance and did not receive any additional information from them. In the mean time, the pinging is becoming more noticable.

Does anyone have any experience with this?

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Eureka, I found it!!!! I have done the fluid cleaner for combustion cyl/ Carbon build up, cleaned the MAF, new spark plugs (that are always clean coming out), retorqued the intake bolts, looked for vac. Leaks with spray (esp by cyl #5, notorious for oil burning), cleaned the EGR, and then some…

At best there were marginal and temporary benefits BUT the other day something occurred to me so I checked it: the fuel pressure regulator vac hose was off! This serves to decrease fuel pressure at idle and should INCREASE FUEL PRESSURE (what the computer ASSUMES the injectors will see) when laboring the engine. When the throttle is opened the injectors don’t have the benefit of “suction”/ vacuum and need increased fuel pressure. If that hose is blown off by a backfire (for example) your engine will run lean at off idle conditions because the injectors are not getting the increase in fuel pressure they should. If the hose falls off the computer re-calibrates itself all out of wack I think.

Since I reinstalled the vac hose there has not been even a hint of ping. The difference is night and day. The fuel pressure regulator is easy to see and get at IF YOU ARE LOOKING FOR IT. And the vac hose is easy to put back on, even without tools. 2 minutes and a little dirt on your fingers will save you allot of grief (and your engine from unnecessarily high combustion temps. I could swear the problem even taxed my cooling system significantly and now the car doesn’t “warm up” so fast on cold days… but I’m not sure about that.

This was a revelation for me, years of anguish/ pinging. :mad2: If this helps you, i.e. you found your hose off, please let me know: markwmonaco@yahoo.com