Detonation help please

[Berg87]

Approx one month ago i began to notice what i believe to be detonation during light to medium-light acceleration. Normally i'm towing a small cargo trailer with some gear total weight about 1500 pounds; this weekend I drove with out the cargo trailer and the same issue was present.

If i use 2/3rds to full throttle i do not notice detonation, either its not happening or i can't tell due to the louder sounds of intake and exhaust.

My Exp has 66k, all orginal except air filter, brake pads, and oil; have used 87 octane everytime but a handfull of fill ups. Still averaging the same MPG since new.

I have searched here about this problem and so far only see two fixes, actually one fix and one treatment for the symptom.

The fix is to have a compentent Ford tech spend time with reprogramming the ECM and the treatment is to use Seafoam or Fords version to clean excess carbon from the pistons. I tend to think i don't have the carbon issue because i do get in the throttle regularly and take the RPM's to the high shift point at least a couple times a week.

If the real fix is ECM programming, how did my ECM get out of wack in the first place? I do not know any compentent Ford techs here in Columbus area. And at Dealer labor rates don't care to fund sombody's mortage payment while they "learn" on my vehicle.

Anyone here know what caused the issue? Any ideas how to correct it? Will using Seafoam every 40-50k be part of regular maintenance?

Thanks in advance

 

[Limited02]

What filter do you have and when did you install it? Have you changed the spark plugs or fuel filter since you have owned it? People say Seafoam works and if you do it right, it would be worth trying.

 

[Berg87]

Limited02....

Air Filter is Motorcraft less than year old, though i need to confirm this and i can check to make sure its in good working order, still original Fuel Filter and original Spark Plugs, although i have purchased replacement plugs...Autolite double platium; said to be nearly the same as the factory plugs.

And yes i've read up on Seafoam usage a few times on other fourms, have never used it on any of my vehicles yet.

 

[Limited02]

On the air filter I was thinking you have switched to an oil type like a K&N. They will sometimes coat the MAF sensor causing your motor to stumble. I would do the seafoam first both in the tank and motor. After burning out that tank, change the filter and plugs. If you want to clean your MAF sensor, you can buy some carb cleaner to clean it. Just unplug the wires, remove the two bolts on top, carefully pull it out and lightly spray the sensors. Let it dry for a few minutes then put it back in. You should be on a good start after doing all this. If you still have problems, let us know.

 

[Berg87]

Thanks for the suggestions, i'll give them a go this weekend. Limited02...

However with only 67k i find it difficult to beileve that something is not out of spec. Also how does cleaning the MAF improve a detonation issue? Aside from this one issue the vehicle runs well with no stumble.

Granted i've went too long on the orginal fuel filter, but not an insane amount.

Anyone else have any imput on this subject???

 

[Limited02]

If the MAF sensor is dirty, it will give an improper reading for fuel mixture. Could cause it to stumble. Cleaning it is very easy and shouldn't take more than 10 minutes to do. Most of the time is just letting it dry out. These are just some basic maintainence that should be done because they haven't been done. It's a start if anything. Hopefully other's will chime in that have had similar problems and can tell you what it was.

 

[republicrat]

The 2001 to 2005 models are notorious for pinging. The timing is advanced too far and there is no knock sensor. Solutions: 1) 89 or higher octane gas eliminates the problem in mine. 2) remove shorting block near PCM (back passenger side of engine compartment), retards timing 3 or 4 degrees. 3) read elsewhere headgasket on these engines commonly fails and lets oil into cylinder 5, which causes the dreaded carbon buildup and preignition. Can be detected by examining sparkplugs. Hope this helps

 

[Berg87]

Republicrat... Thanks for those tips, i've recently ran a tank of 89 thinking i may notice a diiference, but no change at all.
I'll check the plugs this weekend
Is pulling the "shorting" block the only way to retart the timing? And if i reinstall the "shorting" black will the timing go right back to where it is currently?

Had no idea these engines came without a knock sensor, with all the electronics in cars today thought a knock sensor was a given.

Another Ford engine with headgasket issues..how difficult is it to design a proper headgasket? I check my oil level regularly and no signs of fast usage. add less than one quart in 6000 miles

 

[republicrat]

pinging problem

Removing the shorting block will immediately prevent advanced timing and reduce your knocking problems going up hill or pulling a load. You can simply plug the shorting block back in and the advanced timing will return. I've observed this with a timing light. You should also pull the battery cable for a 1/2 h to reset the PCM and then drive the vehicle thru its paces to help the PCM learn how to operate the truck efficiently. I've only been able to get rid of knocking with 89 octane and the shorting block out, or with 91 octane with the shorting block in. Still looking for that majic bullet that will let me run cheaper 87 octane. Cant say I notice any gas mileage drop off with the shorting block out though.

Also try using drive instead of overdrive. Mine pings a lost less with overdrive off. Have you noticed your overdrive operates at around 1700 rpm at 60 mph?. This is just too low for this engine. Should stay above 2000 rpm to prevent pinging.

you could also try cooler spark plugs (some transfer heat and cool off faster after burn than others), or a thermostat that runs your engine cooler, or water spray injection system (dont recommend the latter, but it does work. I dont ping when its raining and cold).

 

[Berg87]

Republicrat.... how did you come to learn the "shorting block" would retard timing? And why is it in use in the first place?

In order to stop any possible internal engine damage i will disconnect the shorting block and a couple other items sugesseted in this post.

However, these all seem to be "work-arounds" or bandaids to the route of the problem. Personally i don't see why having an engine spin at lower RPM's is a bad thing, seems this would lean towards longer engine life and less fuel usage. And in my case i regularly get the engine spining above 4 grand, highway on ramps, long inclines etc.... Therefore i shouldn't have ecess carbon build up, in theory that is.

Guess this problem boils down to two points, what caused the pre-ignition? and what's the best cure?

I'll report back as to the condition of my spark plugs, air filter, MAF sensor after i complete the service work.

thanks again, and please if anyone else has something to add..... let's figure out what is really going on and the best repair to help those that are searching for a fix in the future.

 

[republicrat]

pinging

berg

I learned about the shorting block just like you, by surfing the web. It is also clearly identified in the wiring diagram in chiltons manual. Same book shows 96' and later explorers with knock sensor, not on pre 96 models. This tells me ford realized the flaw and corrected it. There is no noticeable drop in power or mileage with the shorting bar out. The octane shorting bar is grey and about as large as your thumb from your knuckle to the end. Located passenger rear of engine compartment (94 4 liter v6).
I get better mileage on the highway in drive than in overdrive. And better mileage with premium gas than with 87 octane, due to pinging robbing power. My explored runs just fine with the shorting bar out. The timing still advances as you push on the gas, just not by as much (verified by timing light).
I replaced my maf sensor. This was no help.

 

[Berg87]

Quick update....

I haven't had time to perform any of the suggestions yet. I have switched to 93 Octane and the only difference i can tell is the pinging now begins a a couple hundred rpm's higher. approx 2200-2300 versus 2000.

Looked last night for the shorting block, either i didn't see it or its not located in the same area as on the 94's.

 

[rumpledoll]

I suspect that it is not detonation or pre-ignition, especially since you still have it when you tried a 93 octane gas. Rather what you most likely have is the timing chain rattle. There is a TSB on this and the rattle happens right in the RPM range in which you are experiencing the noise.

The only fix is to do the work of the TSB, which means exposing the main timing chain and replacing the tensioner. I have found that a high quality lubricant, such as Amsoil 0W-30 SSO reduces, but does not eliminate this noise. This issue appears to be only a noise issue as there are very few reports of the main timing chain breaking.

Rumple

 

[Berg87]

Hey Rumple, now that makes a lot more sense. To me the actual sound is more mechanical, almost like loose rocker arms.

I was never conviced of Pre-ignition being the cause. On a modern engine what could happen to get continual pre-ignition? Aside from a a bad tank of fuel?

Thanks for setting me straight on this issue

 

[unclemeat]

Try an injector cleaner. Also our engines are notorious for building up carbon on the valves. It can be removed by burning it off. next time you are out driving, select a gear and speed that will allow you to run around 4,000-rpm constantly for about 5-minutes. It is free and works wonders. Higher octane gas is a waste of money in a stock Explorer.

 

[Oldretired59]

hey I also get this ping at start up on a warm engine, also pull a 3500# trailer, will try steps listed here but still wondering about the start up noise

 

[Berg87]

Oldretired59... and others

On my Explorer what "fixed" the issue was some proper and needed maintenance

New Plugs- autolite double Platium
New Fuel Fliter- Motorcraft
MAF cleaning
seafoam treatment used in the Oil
and mostly using a quality Oil Filter and Quality Oil

after the above service, no noise at all.

the noise started not long after i had my oil changed at a Valvoline quick change center. I've always been fond of Valvoline products but when i took my Explorer to a local independent shop the shop owner A) was aware of the noise issue on these vehicles, and B) explained that the oil used at the quick change places is not the same quality as what comes out of the quarts sold in stores. The large tanks of oil is lower quality (prehaps recycled) compared to bottled stuff. I have not researched this, but for now i will believe it. I will contiue to use Valvoline, just not from the large tanks.

if anyone wants to learn more than they thought possible about oil go to "BOBTHEOILGUY.COM" tons of great info


At some point I suspect i will need to correct the timing chain/tensioner issue but for now its running, idling, and starting very smooth.