Excessive spark knock
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From: San Antonio, TX
Excessive spark knock
Well, I tried Mmaxed's ground cable tightening and, in fact found it to be les than snug. I have noticed slightly better shifting since I tightened it.
On my trip yesterday, I experienced a lot of spark knock at 3/4 to full throttle on just about any grade I encountered. None of the grades between the Texas coast and San Antonio are very steep at all, just long and gradual. I was towing my 20' boat (approx 4500 lbs) with 4 adults in the truck. I average 10.5 MPG on the trip, which is not bad at all.
I ran 1 and 3/4 tanks tanks fuel on the trip. The first tank was Chevron 89 octane from the station I use most often. The second tank was Shell 89 octane. I decided to use 89 octane due to a very slight spark knock that occurred on my last trip. The check engine light never came on.
Air and fuel fliters have been changed in the last 5k miles. Both are Motorcraft parts.
As I've posted before, this truck just doesn't have the same grunt that my '05 did. Maybe my engine is throwing a code or could benefit from a reflash of the PCM.
I guess I'll stop by the dealer and have it checked as a warranty issue.
On my trip yesterday, I experienced a lot of spark knock at 3/4 to full throttle on just about any grade I encountered. None of the grades between the Texas coast and San Antonio are very steep at all, just long and gradual. I was towing my 20' boat (approx 4500 lbs) with 4 adults in the truck. I average 10.5 MPG on the trip, which is not bad at all.
I ran 1 and 3/4 tanks tanks fuel on the trip. The first tank was Chevron 89 octane from the station I use most often. The second tank was Shell 89 octane. I decided to use 89 octane due to a very slight spark knock that occurred on my last trip. The check engine light never came on.
Air and fuel fliters have been changed in the last 5k miles. Both are Motorcraft parts.
As I've posted before, this truck just doesn't have the same grunt that my '05 did. Maybe my engine is throwing a code or could benefit from a reflash of the PCM.
I guess I'll stop by the dealer and have it checked as a warranty issue.
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Mine has never had a spark knock that I have heard. Hope the dealer can track it down quickly.
I am jealous of the mileage. That's about what mine makes without a trailer if I'm bucking any kind of wind. Mid 12s on the best tanks.
I am jealous of the mileage. That's about what mine makes without a trailer if I'm bucking any kind of wind. Mid 12s on the best tanks.
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From: San Antonio, TX
I stopped by the dealer yesterday. There are no TSBs addressing this issue, or any for that matter, on V10s.
The service writer didn't think that spark knock under WOT throttle with a heavy load was much of a problem. He asked if I could bring the truck in, with the boat in tow, so they could evaluate it while the knock is occurring.
I'll try a different brand of gas on an empty fill up next time. If it happens again, I may stop by the dealer with the boat in tow.
Has anyone changed the plugs on a 3V motor yet? These late model engines run so lean. There is always black soot in the tailpipe. Makes me wonder what the plugs look like. I wonder if the plugs can even go 50k, much less the advertised 100k under such a lean mixture.
Art, Will the knock sensor throw a code? Maybe it's time to get a scan guage. Or a good excuse at least.
The service writer didn't think that spark knock under WOT throttle with a heavy load was much of a problem. He asked if I could bring the truck in, with the boat in tow, so they could evaluate it while the knock is occurring.
I'll try a different brand of gas on an empty fill up next time. If it happens again, I may stop by the dealer with the boat in tow.
Has anyone changed the plugs on a 3V motor yet? These late model engines run so lean. There is always black soot in the tailpipe. Makes me wonder what the plugs look like. I wonder if the plugs can even go 50k, much less the advertised 100k under such a lean mixture.
Art, Will the knock sensor throw a code? Maybe it's time to get a scan guage. Or a good excuse at least.
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I know some vehicles are supposed to test it, as in advance the timing until it hears it and then back off, and if it never hears it, it throws a code.
But I've never heard of it with the V10.
If the dealer says "no problem" with spark knock, that's a bunch of BS. It IS a problem, and the knock sensor (if the '08 has one?) should make sure it never happens.
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From: SE Texas
They run so lean because they're always running in stoich,and the PCM programing never allows open-loop richening for power/durability until it sees an overtemp condition for the cats,manifolds or O2 sensors. When it does see one of these overtemp conditions-it drowns the engine in a 10:1 (or richer in some strategies) fuel mixture to cool it off. I'm betting bad knock sensor(s),or even terrible OEM tune is to blame for the knocking. In the majority of the OEM programs,if the knock sensor isn't reporting knock,there is an amount of spark advance that is allowed,and spark is added in degrees/second until it knocks or it reaches the PCM's limit for advance. It works the same way in reverse when the sensor "sees" knock-it'll retard the timing by degrees/second until the knock stops or it reaches it's limit for spark retard.
JL
JL
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Johnny, are you a master certified Ford tech?? I've never heard an answer that in-depth before on these boards.
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JL
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Question for you Johnny. The scan gauge in my '08 almost always shows closed loop running empty. Only after several seconds of being floored will it go into open loop. On the other hand with the fifth wheel on it is almost always in open loop. If it is heat triggering the open loop, does that mean that the exhaust is restrictive enough to cause the heat buildup? At least one poster here reported improved throttle response with a free flowing muffler on an '08.
And a big thanks for explaining how this stuff really works!
And a big thanks for explaining how this stuff really works!
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Joined: Oct 2006
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From: SE Texas
Question for you Johnny. The scan gauge in my '08 almost always shows closed loop running empty. Only after several seconds of being floored will it go into open loop. On the other hand with the fifth wheel on it is almost always in open loop. If it is heat triggering the open loop, does that mean that the exhaust is restrictive enough to cause the heat buildup? At least one poster here reported improved throttle response with a free flowing muffler on an '08.
And a big thanks for explaining how this stuff really works!
And a big thanks for explaining how this stuff really works!
JL
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From: San Antonio, TX
So, if I'm understanding this correctly, it would be better for the engine to give it a good flogging on a regular basis.
Also, what's a boxcode?
Thanks for the insight Johnny.
Also, what's a boxcode?
Thanks for the insight Johnny.
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From: Long Island USA
Keeps the cylinders clean, the valves seated, and the BSEG always comes in handy 
Boxcode is the code on the PCM. It's a unique code that says which firmware (flash) you have.
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From: San Antonio, TX
I'm going to revive this old thread.
This is the tunig strategy my truck came from the factory with TDFG5P3 HEX
I had the spark knock that I originally reported when I started this thread.
I got a SCTX3 tuner from 5 Star in, partially in hope of eliminating this problem . It helped, but the knock persisited.
I returned the tune to stock and took it to the dealer. After reproducing the problem, the PCM was reflashed. The new strategy is TDFG6P6 HEX.
For 2 weeks, the spark knock was gone. I hooked up the boat and the knock happened twice. Now it happens randomly. Could happen one day on a steep grade, and the next day be fine.
I haven't tried uploading a custom tune since the dealer changed the strategy. I need to check with Mike at 5 Star and get his opinion.
I'm also wondering if there may be a lot of carbon build up on the valves since there is a heavy coating in the tailpipe (always has been).
Maybe a spark plug change is in order, even though it only has 36k miles onit.
This is the tunig strategy my truck came from the factory with TDFG5P3 HEX
I had the spark knock that I originally reported when I started this thread.
I got a SCTX3 tuner from 5 Star in, partially in hope of eliminating this problem . It helped, but the knock persisited.
I returned the tune to stock and took it to the dealer. After reproducing the problem, the PCM was reflashed. The new strategy is TDFG6P6 HEX.
For 2 weeks, the spark knock was gone. I hooked up the boat and the knock happened twice. Now it happens randomly. Could happen one day on a steep grade, and the next day be fine.
I haven't tried uploading a custom tune since the dealer changed the strategy. I need to check with Mike at 5 Star and get his opinion.
I'm also wondering if there may be a lot of carbon build up on the valves since there is a heavy coating in the tailpipe (always has been).
Maybe a spark plug change is in order, even though it only has 36k miles onit.
Postmaster
Joined: Oct 2006
Posts: 4,171
Likes: 12
From: SE Texas
I'm going to revive this old thread.
This is the tunig strategy my truck came from the factory with TDFG5P3 HEX
I had the spark knock that I originally reported when I started this thread.
I got a SCTX3 tuner from 5 Star in, partially in hope of eliminating this problem . It helped, but the knock persisited.
I returned the tune to stock and took it to the dealer. After reproducing the problem, the PCM was reflashed. The new strategy is TDFG6P6 HEX.
For 2 weeks, the spark knock was gone. I hooked up the boat and the knock happened twice. Now it happens randomly. Could happen one day on a steep grade, and the next day be fine.
I haven't tried uploading a custom tune since the dealer changed the strategy. I need to check with Mike at 5 Star and get his opinion.
I'm also wondering if there may be a lot of carbon build up on the valves since there is a heavy coating in the tailpipe (always has been).
Maybe a spark plug change is in order, even though it only has 36k miles onit.
This is the tunig strategy my truck came from the factory with TDFG5P3 HEX
I had the spark knock that I originally reported when I started this thread.
I got a SCTX3 tuner from 5 Star in, partially in hope of eliminating this problem . It helped, but the knock persisited.
I returned the tune to stock and took it to the dealer. After reproducing the problem, the PCM was reflashed. The new strategy is TDFG6P6 HEX.
For 2 weeks, the spark knock was gone. I hooked up the boat and the knock happened twice. Now it happens randomly. Could happen one day on a steep grade, and the next day be fine.
I haven't tried uploading a custom tune since the dealer changed the strategy. I need to check with Mike at 5 Star and get his opinion.
I'm also wondering if there may be a lot of carbon build up on the valves since there is a heavy coating in the tailpipe (always has been).
Maybe a spark plug change is in order, even though it only has 36k miles onit.
JL
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From: Pa
What rpm range does the ping occur and at what throttle position?
I just got my dads 03' dialed in with his diablosport tuner. The 87 performance canned tune pinged a tad under 3k rpm and quite a bit over 3k rpm especially pulling. I modified the tune by taking out some timing in the affected rpm ranges a little at a time until the ping was gone. This was running 87 octane fuel only and the truck has over 83k on it. I suspect a little timing needs to be taken out as every truck and situation is a little different.
I just got my dads 03' dialed in with his diablosport tuner. The 87 performance canned tune pinged a tad under 3k rpm and quite a bit over 3k rpm especially pulling. I modified the tune by taking out some timing in the affected rpm ranges a little at a time until the ping was gone. This was running 87 octane fuel only and the truck has over 83k on it. I suspect a little timing needs to be taken out as every truck and situation is a little different.