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Discussion Starter #1
Hello,

I recently started a thread where I thought I had a clutch noise, but have come to realize it's engine pinging/knocking. It sounded a bit different than pinging I've heard in other cars, but perhaps the aluminum block affects the tone a little. Another recent thread by Ultraclyde caused me to suspect that this was really the noise I was hearing. So, to see if it was indeed pinging, I filled up with 93 premium, on top of about 1/4 tank of 87 regular. After about 30 miles, guess what? It all but silenced the noise. I can still make it do it a tiny bit if I try hard, but for all practical purposes, it's gone. Much better, for sure. That leads me to believe that there likely isn't anything wrong with my car, rather, the gas is pretty crappy. I'll put 89 into it next tank, and see if all is still well. A few of you guys say you run 89 anyway, and I know it won't do any harm. BTW, I saw $1.99 today for regular! At any rate, this raises a couple of questions in my mind:

1) Does a split second of knock on a hard upshift hurt a motor? I'm realize sustained knocking/pinging is murder on valves, but does a 1/4-1/2 second ping on occasion really hurt anything?

2) I have to wonder if what's coming out of the pump is truly as advertised. Winter is upon us (or soon to be), and winter blends (which are more volatile) are likely being distributed. Everything that has a value has a tolerance. I also wonder if post-Katrina gas, in the interest of higher yeilds, may be on the low end of the tolerance. Meaning, perhaps that pumps which say "87" may in fact be dispensing "86" or even "85".

Any thoughts on this subject fellow 'Stangers?
 

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rainman said:
Hello,

I recently started a thread where I thought I had a clutch noise, but have come to realize it's engine pinging/knocking. It sounded a bit different than pinging I've heard in other cars, but perhaps the aluminum block affects the tone a little. Another recent thread by Ultraclyde caused me to suspect that this was really the noise I was hearing. So, to see if it was indeed pinging, I filled up with 93 premium, on top of about 1/4 tank of 87 regular. After about 30 miles, guess what? It all but silenced the noise. I can still make it do it a tiny bit if I try hard, but for all practical purposes, it's gone. Much better, for sure. That leads me to believe that there likely isn't anything wrong with my car, rather, the gas is pretty crappy. I'll put 89 into it next tank, and see if all is still well. A few of you guys say you run 89 anyway, and I know it won't do any harm. BTW, I saw $1.99 today for regular! At any rate, this raises a couple of questions in my mind:

1) Does a split second of knock on a hard upshift hurt a motor? I'm realize sustained knocking/pinging is murder on valves, but does a 1/4-1/2 second ping on occasion really hurt anything?

2) I have to wonder if what's coming out of the pump is truly as advertised. Winter is upon us (or soon to be), and winter blends (which are more volatile) are likely being distributed. Everything that has a value has a tolerance. I also wonder if post-Katrina gas, in the interest of higher yeilds, may be on the low end of the tolerance. Meaning, perhaps that pumps which say "87" may in fact be dispensing "86" or even "85".

Any thoughts on this subject fellow 'Stangers?
Have you tried a different brand of gas?
I read that Marathon was being sued by GM and others because of their lousy gas quality messing up the sending units, don't know if it would be related.
 

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Discussion Starter #3
I usually go to Albertson's and Racetrac because they're cheapest. Have had no problems until the last couple of tanks. I put in 93 Shell on Sunday, mixed with my 1/4 tank of 87. Sounded good again today back and forth from work. I think I'll try Mobil 89 on my next tank. I wish there was some way for the average guy to check fuel octane, like a test kit or something. While stations do get checked once in a while, I'm sure it's not often. I also still wonder what the tolerance really is. +/- 2 points?
 

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I use 89 octane because I occasionally heard a trace of knock on 87 octane. The switch to 89 octane stopped the valve rattle and I get about 2 mpg better mileage. Engine runs smoothly and I have had no problems with 8400 miles. The improvement in mileage has justified the additional cost.
 

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About all the questions regarding damage which may occur as a result of this 1/4 - 1/2 second spark knock which is noticed on spirited upshifts and punching the gas. In the hot summer months here in Pa, this knocking can be heard on virtually every upshift at almost any RPM. Ford engineer tells me this is normal as the knock sensor detects the detonation and retards the timing to stop the detonation. I inquired about getting the extended warranty for free if he is so sure that this is "normal" because I feel this is going to lead to severe damage over time, most likely AFTER my warranty expires. He said that would be a good idea and that he would try to get it for me. After speaking with my service manager, he said no, we won't do it. I asked my service manager what happened and he said get a lawyer. Ford sells the car with lines like Mustang is built to be driven hard and fast. Where is the fun in that when the car sounds like a piece of crap every time you upshift? The engineer said I should absolutely NOT run any higher than 87 octane in the car or Excessive carbon buildup or worse problems will occur. I have another date with the engineer in a couple of weeks to follow up on Fords latest attempt to explain / fix this "normal" whatever it is that is happening. If this is normal, then why are they trying to fix it? Does anyone know what will really happen if I run 89+ octane in the car?
 

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Discussion Starter #6
I have to wonder about those who have done reprogramming of their ECU, from Superchips or others. While we shouldn't have to do this just to run regular gas without knocking, has anyone changed their timing curve without resulting in knocks/pings?

Sounds like Ford needs to do a TSB on engine timing curve and implement it. If these motors are designed to run on 87 octane, then they should do so without knocking. I'm taking mine into the dealer sometime during the next two weeks to have the TSB concerning front end popping taken care of, and I'll ask them about the pinging, and hopefully get someone to listen to it. Of course, I'll have to put 87 octane back into it. I'll add to this post or start another when I hear what they say.

As far as the carbon issue is concerned, I find it hard to believe that running 89 instead of 87 would be that harmful.
 

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Thanks rainman! The only way Ford is going to acknowledge this thing, whatever it is, is if enough people bring their cars in to have it checked out. My owners manual does not say that using higher octane would cause damage. It only suggests that any problems that you may be having could become more pronounced with the higher octane fuel. I really don't know what that means. The only thing it does for me is make my spark knock go away, which does not sound like a bad thing to me. Thanks again, and please post the dealers comments on your spark knock concern.
 

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This may sound a bit crazy, but why not get a good tuner and dyno your car, and have the engine managment system readjusted by a professional tuner?? they can tune your car to your specific environments, and to what ever fuel you want. I run 93 Octane in mine, but I have to since I have a blower and need the slower burning fuel to reduce detonation. The reason you should not use higher than 87 octane in stock vehicle is because of the slower burning fuel, causing bulldup. One or two tanks wont hurt to try, to determine if the knock goes away. IF it does, then try different fuel, or have your timing backed off a degree or two.
 

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Discussion Starter #9
No, that doesn't sound crazy at all. It's basically what I meant a couple of posts back when I was inquiring about those who've had custom tunes done. While we shouldn't have to do this to a bone stock car, I suspect I'll get better results by going this route vs the dealer.
 

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rainman said:
No, that doesn't sound crazy at all. It's basically what I meant a couple of posts back when I was inquiring about those who've had custom tunes done. While we shouldn't have to do this to a bone stock car, I suspect I'll get better results by going this route vs the dealer.
talk with Jim at JDM Engineering. They have KickA** tunes!

www.teamjdm.com

Tell him chuckles sent ya!
 

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zman99 said:
About all the questions regarding damage which may occur as a result of this 1/4 - 1/2 second spark knock which is noticed on spirited upshifts and punching the gas. In the hot summer months here in Pa, this knocking can be heard on virtually every upshift at almost any RPM. Ford engineer tells me this is normal as the knock sensor detects the detonation and retards the timing to stop the detonation. I inquired about getting the extended warranty for free if he is so sure that this is "normal" because I feel this is going to lead to severe damage over time, most likely AFTER my warranty expires. He said that would be a good idea and that he would try to get it for me. After speaking with my service manager, he said no, we won't do it. I asked my service manager what happened and he said get a lawyer. Ford sells the car with lines like Mustang is built to be driven hard and fast. Where is the fun in that when the car sounds like a piece of crap every time you upshift? The engineer said I should absolutely NOT run any higher than 87 octane in the car or Excessive carbon buildup or worse problems will occur. I have another date with the engineer in a couple of weeks to follow up on Fords latest attempt to explain / fix this "normal" whatever it is that is happening. If this is normal, then why are they trying to fix it? Does anyone know what will really happen if I run 89+ octane in the car?
I had a 94 Lincoln Town Car (4.6L) that was supposed to run on 87 and I put 89 octane in it to get rid of the knock - sold it at 10 years old and 143,000 miles and never had a single problem with the engine. Maybe I'm wasting my money, but I have had the same knock problem on three of my four cars with 4.6L engines - only exception is my 2004 Mercury Grand Marquis - it runs OK on 87. Used 89 octane in the other three - one was the Lincoln noted above. The other was a 95 Crown Victoria (122K miles) and the third one is my 05 Mustang.

In all three cases, the higher octane got rid of the knock. I got 24 MPG highway on the Lincoln, 28-29 MPG highway on the Crown Vic and I get 25-26 MPG highway on the Mustang, 17.8 MPG around town so far, 23 MPH average speed according to the info center.

When I ran 87 octane in the Mustang it was getting about 23 MPG highway. Friend of mine in our Mustang club has had a similar experience regarding better mileage on 89 octane, so I don't think I'm imagining things...
 

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Is there a check engine light on? There has been a problem with the EGR passages in the thottle passages clogging up with carbon....on the older 4.6's
 

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I believe EGR is controled by the VCT on the new 3V engine. During light cruise the cams are used to allow some of the exhaust back into the cylinder by retarding them.
 

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I have played with various gas brands and grades.

My mustang likes Chevron, BP and Amoco.
Put Speedway in it and it runs like crap.
Shell runs great but milage is very low with it.

89 octane seems to let the car run smoother. 92 has no affect over the 89.
So mine gets 89 all the time. 87 seems to let the car run a little rough.

In my Saturn (97) - it pings, knocks and completely hates 87 octane
Car has under drive pulleys, intake, Silverstone plugs, Magnacore wires, h/o alt, etc. Saturn told me once that 89 octane would hurt the car...............100.000 miles and running great on 89 and 92 octane.

My personal opinion - different brands of gas do better than others and I suspect even between regions of the US that can vary. Just my 2 cents.
 

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Discussion Starter #15
Took my car to the dealer yesterday to take care of the front end pop TSB, and asked about the pinging issue. The good news is, the service they did took care of the front end pop issue. The bad news is, I was told that momentary pinging is normal. I had hoped that this condition had been reported before. The service manager said that this is normal, and in fact, his Crown Vic has done this all along. Part of me is inclined to believe that he's right, that a momentary ping is not harmful. However, I'm still concerned as to the long term effects. My concern is that by the time I find out he's wrong, I'll be out of warranty and sh** out of luck. I'm seeking 3rd party help, in any way I can get it. For starters, I've asked a local shop owner who has a radio show and newspaper Q&A column about this. I'll post if I get any meaningful reply.

If I haven't done so before, thanks all for your help.
 

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zman99 said:
About all the questions regarding damage which may occur as a result of this 1/4 - 1/2 second spark knock which is noticed on spirited upshifts and punching the gas. In the hot summer months here in Pa, this knocking can be heard on virtually every upshift at almost any RPM. Ford engineer tells me this is normal as the knock sensor detects the detonation and retards the timing to stop the detonation. I inquired about getting the extended warranty for free if he is so sure that this is "normal" because I feel this is going to lead to severe damage over time, most likely AFTER my warranty expires. He said that would be a good idea and that he would try to get it for me. After speaking with my service manager, he said no, we won't do it. I asked my service manager what happened and he said get a lawyer. Ford sells the car with lines like Mustang is built to be driven hard and fast. Where is the fun in that when the car sounds like a piece of crap every time you upshift? The engineer said I should absolutely NOT run any higher than 87 octane in the car or Excessive carbon buildup or worse problems will occur. I have another date with the engineer in a couple of weeks to follow up on Fords latest attempt to explain / fix this "normal" whatever it is that is happening. If this is normal, then why are they trying to fix it? Does anyone know what will really happen if I run 89+ octane in the car?
Hey Zman99,
I have been running 91 octane since August. I think its cheap insurance, especially since I run the N20 on ocassion. Anyway, I have pulled the plugs several times to check for detonation (because of the N20) and they look perfect. NO CARBON BUILDUP at all. On my dynotune, we set total timing at 30 degrees, 27 for the N20 tune. I never hear my engine knock.
 

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Steven6095 said:
I have played with various gas brands and grades.

My mustang likes Chevron, BP and Amoco.
Put Speedway in it and it runs like crap.
Shell runs great but milage is very low with it.

89 octane seems to let the car run smoother. 92 has no affect over the 89.
So mine gets 89 all the time. 87 seems to let the car run a little rough.

In my Saturn (97) - it pings, knocks and completely hates 87 octane
Car has under drive pulleys, intake, Silverstone plugs, Magnacore wires, h/o alt, etc. Saturn told me once that 89 octane would hurt the car...............100.000 miles and running great on 89 and 92 octane.

My personal opinion - different brands of gas do better than others and I suspect even between regions of the US that can vary. Just my 2 cents.
allow me to try and clarify Uh i mean further confuse the situation...

regular miid and premium for the most part have the same burn rate... kerosene and diesel have substantualy different burn rates from gasoline.

octane rating does not indicate a fuels burn rate but rather its ability to resist ignition as it is compressed.

octane is a type of hydrocarbon like propane and butane, one such variant of octane isooctane is very compression resistant and burns smoothly and has been given an octane of 100 as a result octane ratings where a measure of the mixture of octane and heptane which is a filler of sorts and has a very poor resistance to compression ignition. and is the other major constiuent in straight run gasoline. straigh run was achieved thru early refining techniques having an overal octane rating of 70 and a yeild of about 25%. cracking and isomerization improve both yields and octane ratings.

now combustion is not realy an explosion inside your engine but a smooth controlled burn from the plug to the ouside of the cylinder

there are two kinds of engine noise a ping and a knock, a ping is a load condition combining with a hotspot on the piston or chamber(carbon buildup, bad squish band design on the piston etc etc) that ignites the fuel air combo before or after the actual spark. this would be occuring very close to the actual ignition point ususaly causing a collision of flame propigation fronts inside the cylinder that results in a ping that sounds like little hammers tapping on the valves.(usualy cured by a good blast on the highway to clean out the carbon or a switch to a higher ocane fuel that will resist ignition from the hotspot.or pressure.

the other type of preignition is a knock. knocks result from a very early ignition of the fuel. the purpose of ignition timing in an engine is to create a situation where max cylinder pressure is created just as the cylinder starts to travel downwards when the fuel is ignited to early the cylinder pressures build before the cylinder gets to the top. literly like double bouning a trampoline hammering the components with max pressure before the piston heads down and trying to spin the whole thing backwards this occurs on very high compression engines with low octane fuel. they literaly diesel, igniting the fuel before the spark plugs fire. if your engine has ever run on this is an indicatior. it can also be caused by to much timing advance firing the fuel way to early.


so a ping is an issue of 2 flame fronts colliding. if the fuel is ignited and burns evenly from point of igntion as designed then no ping occurs. a knock is a pressure issue caused by the fuel lighting and burning to soon before tdc causing a huge pressure spike at top dead. one kills motors the other is annoying.

since the mechanical compression of our motors is not quite (close mabye) sufficent to ignite an 87 octane fuel it is the computer lighting the fuel causing a rise in cylinder pressure combined with a poor squish band or other combustion chamber factor that is causing the rest of the mix to light out of order resulting in ping. cure... compression resistant fuels that wont burn out of order or less initial timing to reduce pressure and therefore eliminate the creation of flame front 2 as the subsequent rise in pressure does not preignite the rest of the mix (this is why you can increase timing with good gas as it resists the tendency to pressure ignite thus you can increase overall cylinder pressure while still getting a controlled burn and recieving the benefit of the increase in power from the higher overall pressures)

therefore until ford changes the design of the piston or head the solution is less timing or better gas


in the modern era where demand is high and gas is a shitmix of chemicals that result in an equevalent octane rating , different refineries have different demands for their base products so the actual consitiuence of gas may vary greatly, each producer also has their own special blend. there are also ways to manipulate octane ratings such as adding alcohol to fuel mtbe tel etc. alcohol does actualy slow the burn rates to help the fuel perform better during octane rating testing ( it should be noted that alcohol combinations in in excess of 20% can and will match the real world performance of leaded fuels no major producers i am aware of offer this high a concentration)

i have noted from personal experience that the one alcohol blend around here available in up to i think 10% in a premium fuel does not perform as well in its ability to resist compression knock or dieseling when compared to a fuel with non alcohol additives with the same ocane ratings, however due to its slower burn on a lower compression engine you can raise the initial timing to push cylinder pressures closer to the fuels compression max to gain power. i am going to avoid all together the subject of bs research octane numbers, fuel additives and octane modifiers and the sneaky lowdown oil companies resistance to higher alcohol concentrations and less reliance on pantentable alternatives like mtbe and historicaly tetra ethyl lead

suffice it to say since the mechanical compression of our engines is reasonably high in combination with the early timing my advice is avoid alcohol blends and stick with a brand name fuel provider as the shite all goes to the independent stations. bump the grade if it helps. whoever said higher octane will harm an engine is full of it. avoiding low grade gas is more important. and if you want it eliminated all together get a tune and pull back the timing a few degrees. (she might only make 290 instead of 300 but no ping) or up the fuel grade. and avoid leaded race fuels at all costs as they will kill your cats before you can pull out a hundred and use it to light a smoke.

if you ever wanted to know more about motor fuels check out
http://chemistry.about.com/cs/howthingswork/a/aa070401a_2.htm

and to boggle your mind with corporate irresponsiblility
http://jove.eng.yale.edu/pipermail/eas-info/2005/000792.html
ahhhhhhh tired now
:kooky:
 

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Yeah!, What he said! I was thinking the exact same thing! :rolleyes:

Actually TimeMachine, that was good :worship :worship :worship ....I didn't know the difference between ping and knock...now I do. I feel like I just graduated a class.

So ping = annoying, knock = engine killer, cure = less timing, higher octane, or both. Avoid crap gas given to independent stations, and higher octane will not harm your engine---unless you put leaded race gas in the tank.

Did I pass?:kooky:
 

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TM, excellent post!
 

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Wow! After all of that, I have a question. Instead of paying big bucks for the premium gas, what about just adding octane boost? It's what I do for my 1966 coupe and has worked fine so far (since it was originally built for leaded fuel). No problems with the GT, yet, so I ask because my truck has really started knocking lately (of course) at cold starts until it warms up some. I'm wondering if it's just the mileage on the truck (111,000), or the fuel I'm running. My dad suggested just adding a quart of Slick 50 next time I change the oil, or next time it needs a quart; and to add some fuel-injector cleaner....
 
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