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I took my 2006 Dyna Super Glide in for a 1,000 mile service and inquired about putting in a set of HD platinum or Screaming Eagle platinum spark plugs in. They told me that platinum plugs sometimes give a false engine fault code with the EFI models because of an ion sensor within the computers software. The ion sensor informs the computer of an engine misfire. I assume the resistance of the spark is constantly being measured. I don't think there is an actual "ion sensor".

Does anyone have any information on this?
 

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Get a standard plug, and change them every 10k.

Thorns
 

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steverxr said:
I took my 2006 Dyna Super Glide in for a 1,000 mile service and inquired about putting in a set of HD platinum or Screaming Eagle platinum spark plugs in. They told me that platinum plugs sometimes give a false engine fault code with the EFI models because of an ion sensor within the computers software. The ion sensor informs the computer of an engine misfire. I assume the resistance of the spark is constantly being measured. I don't think there is an actual "ion sensor".

Does anyone have any information on this?
sounds like bs.
 

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Total Nutcase
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The dealership is correct. Another name for Ion sensors is Spark Knock Retard sensors. They detect denotation and retard the timing to protect your engine.

"Ion Sensing System – this system uses ion-sensing technology to detect detonation or engine misfire in either the front or rear cylinder by monitoring the electrical energy at the spark plug following every timed spark. If an abnormal level of energy is detected across 2 or 3 spark firings the ECM responds by retarding spark timing in the problem cylinder as needed to eliminate it."
 

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my dealer told me a similar story on my 04 FXD. Said any plugs ofther than OEM (specificly no SE splitfires, etc) would cause the ecm to read the plug wrong. I bought the SE plugs anyway, and had no problems, untill Jan after a long storage...back cylander would not fire, (there is another thread on that today) Swapped to OEM plugs, and it fired right up
 

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Well I am running Iridium plugs and after 900+ miles they are running just fine. They don't say Harley-Davidson on them either. Oh and if Platinum plugs are so bad for HDs why do they sell them at the dealership? :dunno:

Some other useful information Spitfire spark plugs have been proven on a dyno in a car magazine to reduce HP/TQ and fuel mileage. Just wish I could remember which mag it was. Was done about 5 years ago I believe.
 

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I was told unless you have a hi-comp motor to stay with stock plugs
 

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wkohn said:
Oh and if Platinum plugs are so bad for HDs why do they sell them at the dealership?
Because there are lots of Harleys without FI? And because they're another gimmick the dealers can make money on?
 

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murphdog said:
Because there are lots of Harleys without FI? And because they're another gimmick the dealers can make money on?
Ah come on now. You mean the spark plug knows if the bike is FI or carb. Remember back in the thread that the problem was on a FI bike. Mine is FI and runs fine. Dealers won't like them because they will not need to be changed for 60k miles. Now a carb bike will not have the same sensors as a FI bike and will not have the same BS story about the sensors to fall back on. But will the dealer use it anyways? You bet your life he will cause he wants to sell you his over priced old technology HD plugs every 10K.

The auto companies have been using Platinum plugs for years with FI systems. And guess what no problems. Other than the plugs last longer and help to give better performance. We wouldn't want that now would we?
 

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I had aproblem with the split fires. But the Platium are fine on my scoot.
Sparky
 

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wkohn said:
Ah come on now. You mean the spark plug knows if the bike is FI or carb. Remember back in the thread that the problem was on a FI bike. Mine is FI and runs fine. Dealers won't like them because they will not need to be changed for 60k miles. Now a carb bike will not have the same sensors as a FI bike and will not have the same BS story about the sensors to fall back on. But will the dealer use it anyways? You bet your life he will cause he wants to sell you his over priced old technology HD plugs every 10K.

The auto companies have been using Platinum plugs for years with FI systems. And guess what no problems. Other than the plugs last longer and help to give better performance. We wouldn't want that now would we?
Automotive vehicles in years past used a knock sensor to detect knocking. Use of ION sensors or the monitoring of amperage used to a given spark gives a reading of individual cyl. info. The plugs would need to pull the same amperage as the OEM to work properly. It would have nothing to do with platinum,iridium, or whatever else electrode or electrode covering. The plug beeing used would need to meet the OEM resistance characteristics. Otherwise the amperage pulled that the ECM is reading will be out of specs and the spark advance etc would be messed up. Most likely giving a code too.
 

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man4mopar said:
Automotive vehicles in years past used a knock sensor to detect knocking. Use of ION sensors or the monitoring of amperage used to a given spark gives a reading of individual cyl. info. The plugs would need to pull the same amperage as the OEM to work properly. It would have nothing to do with platinum,iridium, or whatever else electrode or electrode covering. The plug beeing used would need to meet the OEM resistance characteristics. Otherwise the amperage pulled that the ECM is reading will be out of specs and the spark advance etc would be messed up. Most likely giving a code too.
No codes. Now what?
 

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iridium plugs

while I did increase engine size I stayed with flat tops so I assume it is standard compression (high tq low hp) . would iridium plugs be any improvement or a waste of money? do they have longer life?
 

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wkohn said:
No codes. Now what?
Not one person is debating whether or not your bike is working or not. What they are telling you, albeit with a lack of listening, is that the system is designed for the stock plugs or ones that measure the same resistance. Harley isn't trying to scam anyone here, they designed a system around these plugs and it's their recommendation to use them. The stock plugs aren't that expensive and if you are going to buy a Harley don't complain about the cost of plugs, everyone knows what they are getting into. Now that doesn't mean that the everyday Harley owner who clearly knows more than the engineers that designed these bikes can't run whatever plugs they want and tell HD to pack sand.:whatever: I've personally seen where non Harley plugs pop a code and so have other people and I've ran other plugs without codes for many miles, but at some point in time the system will notice an irregular reading and a code may result. If you don't have a code you may never get one, but the system IS looking for a specific measurement that was programmed using STOCK Harley Davidson plugs.
 

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wkohn said:
Ah come on now. You mean the spark plug knows if the bike is FI or carb. Remember back in the thread that the problem was on a FI bike. Mine is FI and runs fine. Dealers won't like them because they will not need to be changed for 60k miles. Now a carb bike will not have the same sensors as a FI bike and will not have the same BS story about the sensors to fall back on. But will the dealer use it anyways? You bet your life he will cause he wants to sell you his over priced old technology HD plugs every 10K.

The auto companies have been using Platinum plugs for years with FI systems. And guess what no problems. Other than the plugs last longer and help to give better performance. We wouldn't want that now would we?
I believe it's the FI ECM knowing what the spark plug is, not the plug knowing if the bike is FI or carb. Some FI people have had problems with non-stock plugs, some haven't. I don't think anyone in this thread with a carb has said a dealer told him he would have problems with any kind of plug, platinum or otherwise. You asked why dealers sell platinum plugs, I said because there are lots of Harleys without FI. Some FI bikes throw codes with platinum plugs, carb bikes don't. Why are you having a problem with that? I don't consider $3 old technology plugs overpriced, but I do $16 triple platinum ones. Is there some type of correlation between auto companies using platinum plugs without problems and Harleys? I couldn't be happier that your bike runs fine, but I don't understand what your argument is.
 

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wkohn said:
No codes. Now what?
Without monitoring the pids I would say your platinum plugs are close in range of spec. Though who knows if it is optimizing advance and retardation of spark timing correctly.Since the ION sensing was calibrated for the spark plug harley uses and says to use.
 

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murphdog said:
I believe it's the FI ECM knowing what the spark plug is, not the plug knowing if the bike is FI or carb. Some FI people have had problems with non-stock plugs, some haven't. I don't think anyone in this thread with a carb has said a dealer told him he would have problems with any kind of plug, platinum or otherwise. You asked why dealers sell platinum plugs, I said because there are lots of Harleys without FI. Some FI bikes throw codes with platinum plugs, carb bikes don't. Why are you having a problem with that? I don't consider $3 old technology plugs overpriced, but I do $16 triple platinum ones. Is there some type of correlation between auto companies using platinum plugs without problems and Harleys? I couldn't be happier that your bike runs fine, but I don't understand what your argument is.
Well I have a hard time believing the dealer about stuff like this because of hearing people being told by a dealer if you don't use HD oil, filters, tires, polish (okay I'm stretching that one but you get the idea) that your warranty will be voided. So when someone tells me that the dealer said. I pretty much don't believe them.
 
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