Serious engine detonation

[ACBlessing]

Hi all,

I got my new exhaust system put on this weekend and took my X for a drive where upon climbing uphill on the highway, there was serious detonation all the way up the hill. I believe it's detonation because when I let off the gas, it goes away, when I get on the gas it comes back. I wanted to know from the experts here....

1. Do I need to reset the computer now that I have a new exhaust?

2. Would a new exhaust contribute to serious engine detonation?

3. Should I have Ford reprogram the computer for better timing?

ANY ideas and experiences would be greatly appreciated since I probably missed the solution completely.

Thank you much,

AC

 

[aldive]

Originally posted by ACBlessing
1. Do I need to reset the computer now that I have a new exhaust?

I would definately reset the computerl it can't hurt. Did you make any other mods?

 

[ACBlessing]

No other mods except the KKM I got a month ago and I reset the computer then...

I just don't know because it's either coincedence that I get pinging the same day I drive out with my new exhaust OR the exhaust is contributing to pining because I haven't reset the puter....just not sure.

Oh, another thing comes to mind....I did take my X to Ford to program the GEM module for my larger tire size and they said they updated my main computer too...hmmm

AC

 

[ACBlessing]

No other mods except the KKM I got a month ago and I reset the computer then...

I just don't know because it's either coincedence that I get pinging the same day I drive out with my new exhaust OR the exhaust is contributing to pining because I haven't reset the puter....just not sure.

Oh, another thing comes to mind....I did take my X to Ford to program the GEM module for my larger tire size and they said they updated my main computer too while they were at it...hmmm

AC

 

[Rhett]

I have been told that some exhaust can cause your truck to run lean in low rpms...which would be like when you let off the gas..not at wide open throt...and running lean can cause detonation. But I am not sure if this is true or not, it's just what someone once told me...

Hopefully someone else knows more, I personally wonder if it's not just some hot air..

FYI, with my insulated airbox/intake, I don't get detonation anymore. It's weird but true. I can run 87 oct gas now!

 

[ACBlessing]

Thanks for your imput.......the detonation occurs when I'm going uphill under wide-open throttle (or near WOT)...it was really bad. If I could, I'd set the timing myself.

Anyone else?


-AC

 

[jemail]

Have you looked to see if all the sensors hooked to your engine are attached fully? I seem to remember that the Ford engines have a knock sensor, so it would hear the knock, tell the computer, then the computer will retard your timing until the knock went away (or your truck stalled for lack of power from the retarded timing.

 

[Rhett]

I thought only the SOHC engine trucks (97+) had the knock sensor. Is that right?

Anyway, AC I would for sure reset the computer. Then put in gas you normally use, and then go run some roads that cause the pinging. If that doesn't do it, run your tank down to about empty, and dump in some fuel injector cleaner. Then fill up. It will still ping on this tank. But then on the next tank, it might stop. That was my experience. It took the tank of injector cleaner running thru it for a week or so and that cured the detonation.

Since you have a 2000 you don't have carbon buildup. Don't let a dealer or mech give you that line. Seems like a lot of V8 people (particularly Mountaineer owners) have reported the detonation. Maybe it could be a timing problem after all.

 

[Xplor]

AC, I guess welcome to the club. I have the same problem with my '00 V8. I posted a similiar thing like a month or two ago. The detonation usually occurs when the weather is warm out..like 85 and higher. It only makes the noise when I go over a overpasses hills, etc. It was quite warm up there where u live at now? The only mod I done is just a K&N drop in and running Mobil One. I took mine to the dealer and told me it's "normal". Are you running regular octane or premium? I am running premium, its does help a lot, but I still get a little noise. Oh yeah, be careful what the dealer does to the ECM (computer) because they can get the to where is doesn't ping, they pretty much re-program the computer for less power. Thats if you really want them to fix the detonation for you. I didn't want that!...I bought a V8 for power! Also, read your owners manual, in the fuel section...it will say pinging , knocking is normal..not straight from the manual, if u read it it will give ya a better describtion. I want to get the Superchip, but am afraid that would make the detonation worst, especially that I am living in a warm climate. In your case, try to reset your computer by disconnecting your battery for a couple of minutes. If that doesn't work buy premium fuel (if you are not using it), and reset the computer again.

 

[ACBlessing]

Thanks all and thanks Xplor.......yes, I was going uphill at nearly wide open throttle (about 55mph) on one of our hottest days (95 degrees) using 87 octane fuel.

I let Ford reprogram the ECM since I don't have a Superchip but it seems they would program it for more power since advancing the timing to eliminate the ping would also yield more h.p. not sure.

I do want to get the Power Programmer III OR if I can connect my laptop to my X I'd do it myself. I'm used to setting timing on my older cars and now can't do it and it ticks me off the dealer has all the control here. I don't believe the severity of my pinging is normal whether it says in the manual or Ford tells me. Pinging will eventually ruin the motor.

Thanks for the great ideas though. I will reset the computer and try 89 octane with some fuel injector cleaner this time. I'll also look for disconnected sensor wires, etc.

If anyone else is experiencing this please chime in.

AC

 

[SteveVB]

some other thoughts

do a good mechanical check for vacuum leak, check the vac hoses etc.

When the pinging happens is it after a driving style change- ie going from mostly cruising to hitting the gas? Could be the adaptive stratagies in the computer. It is still tuned the engine for cruising when you stomp on the gas. This seems easiest to notice when two drivers change- my wife complains about our cars constantly, but when I get in to drive I dont make them "rattle" as she calls it. She drives with the throttle open allthe time causing bogs etc. not really paying attention to what the vehicle wants in terms of throttle input, etc. Picked this up from a Mustang racer who claimed the computer treated road driving different than the track and that he needed to adjust his driving to get the computer to relearn his style when he got to the track. Thought he was blowing smoke until I read about the adaptive stratagies section in the EEC book that I have. Food for thought.

 

[timfretwell]

Did you ever solve your pinging problem? I have the same problem on my 94.

 

[yob_yeknom]

I don't have a answer to this problem. Sorry. I can say don't get a Superchip to solve detonation problems. When I installed my Superchip, it made my knocking problem much worse. I'm coming up on 100,000 miles though, so I have to expect a little knock.

timfretwell, it's a miracle!! A member from somewhere close to me. I'm only 20 minutes from Roanoke. Ever want to go wheeling sometime?

 

[Xplor]

Update

Well, Here's what I did couple of days ago. I bought Chevron fuel sytem clear and filled it up with 87 regular. Then, I disconnected the battery for 10min to reset the computer. I was running premium and I still get the pinging(spark knock) on highway speed with some stress on the engine before. Since I tried these 2 things with the cleaner and the additive, it pinging like crazy. After I a week till the next fill up I just ran regular and reset the computer again, and I still get the same results which is a lot of pinging. I called serveral Ford dealerships and talked the service advisors about the situation. One told me that he gets quite of few V8 explorers with the problem. I made a appointment the following day to have it check out. As a result, the tech de-carbon the throttle body with some cleaner couple of times and the fix was somewhat better, but I still get pinging. I called the servce advisor again, and told him and he said the one last solution is to turn the octane level down on the computer. I don't want that, cause I would lose power. Now, its been couple of days after it been from that sevice and I could smell a odor around the engine and I turn it off, which must be from that cleaner they used.

Now, What should I do? Should I go out and buy some more throttle body cleaner and clean it myself. Would I be overdoing it?...since the dealer tried de-carbon it. I read couple of post on here awhile back about cleaning the mass airflow sensor, can this also cause the pinging problem? I don't see how it would cause it from this sensor. I was thinking about trying a mid-grade gas..which i think it is 89. My V8 is '00 and still have around 20k on it.

This needs to be solved somehow, without tuning the computer down. Any advice?

 

[timfretwell]

yob_yeknom in Rocky Mount (Moon shine capital of USA), we are practically neighbors! My folks live in the great metropolis of Union Hall, just down the road from you. Let me know when your going 4-wheeling. I need some of that red Franklin county mud under my Yokohama Geolanders!
Later

 

[LXTra]

Xplor, if you are taking your Merc to the dealer for detonation and he is spraying carb cleaner in your throttle body..GO TO A DIFFERENT DEALER.
But...they may be trying to clean the MAF sensor, which does make sense. If your MAF is dirty, it will tell the computer that LESS air is going into the motor, and the comp will lean out the mixture possibly causing detonation. The intake and exhaust mods that you've done will also lean things out a little until the comp relearns things. I would definitely try resetting the comp again by disco'ing the battery and opening 1 or more doors for at least 10 minutes.

One of the tricks we mustangers use to do a bit of tuning on the mixture is by setting the base voltage on the TPS(throttle position sensor). Pierce the green wire(not sure if it'll be green on yours) with the positive probe on a voltmeter and any ground with the negative. With the key in "Key on engine Off" position you should get a reading of about .90-1.0 Volts. If you loosen the mounting screws on the TPS and move it around you can get the voltage to change. Try and get it to at least 1.0V if not a little higher. This might help.

P.S. I haven't been stuffing my nose under the hoods of any '00 Mountaineers lately so consult a good service manual for the TPS location(if it even has one). It will be the black thing with wires coming out of it mounted on the throttle body.

If you still have the original plugs and plug wires I would chuck them for good after market replacements, possibly going one temp range cooler with the plugs. Also check your intake system for leaks. If it is not sealed up well it could be sucking air in from behind the MAF, also sucking in hot air from under the hood, both of those things will also contribute to detonation. An easy way to check for an intake leak is to spray a little carb cleaner around the joints in your intake system while the motor is idling. Start just behind the MAF. If while spraying the joints the rpm surges, you have found a leak.

Sorry about the length of this post but I hope this helps a little....Jim

 

[LXTra]

One more thing. Definitely clean the MAF. But you need to find out what solvent can be safely used to clean it. The wrong type could kill it and it's not a cheap part to replace. Keep us posted on any progress...Jim

 

[Xplor]

LXTra, thanks for your reply! Everything you said seems to make perfert sence. However, I just discovered a Ford modification label under the hood. It was hand written..Repro PCV with some new code, but I believe it meant PCM. I know. Another thing I notice that the cleaner that they used went in through a fuel line. I haven't seen any traces of finger smudge around the throttle body (I know because my engine is clean, with fine dust on top of it therefore, untouched). So they didn't take that off. The service advisor told me that a cleaner was used and I even asked him if they touched the computer and he said no. Well, now am really starting to fustrated, since I saw that stricker that was attached. If they reprogrammed the computer, then I thought I would feel the lost of power, but it felt the same. I had all the stock airbox in and did the battery disconnect before I took it to the dealer. I am going to call back the dealer and ask them if they really did do something with the computer, it would tick me off it they did. I still get a spark knock. I will probably do the MAF sensor cleaning, to see if that a problem. I'll look for a circuit board cleaner for that. There was a somewhat a improvement from that 1st visit, but the knock still exist. The TPS part, I will mention it to the advisor whwn it goes back. The only time the spark knock occurs it when the engine warms up and going ata steady highway speeds alone with going over hills, overpasses, etc. Thanks again. Anyone else wanna share there thought and advice, feel free.

 

[Rhett]

One possibility, and it may have already been discussed here, is that the entire powertrain control module (PCM) aka computer..needs to be replaced. It seems unlikely on such a new vehicle that the computer could be out but I have heard of it happening. Also it would concern me (to the point that I would consider the PCM damaged) if the computer had been reprogrammed at least one time and the problem persists.

Another possibility is that one or more of the O2 sensors are misreading. This can cause a lean condition because the sensor tells the PCM how much O2 is in the exhaust stream. The PCM then in turn modifies the firing based on this information. Again, however, I think this is an unlikely possibility on a newer vehicle such as yours. The O2s should last many years.

 

[Xplor]

okay my Ex is going to the dealer on 10/3, this time a different one. I wish I could will stand and watch the techs. I know I can't due to the shops insurance policy. And the fact that the shop area is in a different area of the service advisor area. I wonder if I want to leave a note with these possiblity to look at. It seems it could be from anything from the MAF(MASS), TPS, CPU, O2s, vaccum leaks, exhaust manifold, and whatever else that everyone was suggesting. I know this is going to be hard to pen point with the technology with the today's vehicles. I guess I will find out what this dealer will do.