Spark Knock in my Harley F150
Hey Guys. :-wink I normally hang out in the 67-72 truck section but I'm having trouble with my 2003 Harley F150. It has Diablo programer,s/c power pulleys,12# boost,throttle body,C&L air duct,and Cold air intake. These have all been in it for years. Nothing changed except maybe the gas here in Phoenix Arizona. It does seem to be better with Chevron.
Driving home from work it is normal at first. After maybe about 10 miles it starts spark knocking under load up a grade. The farther I drive it, it spark knocks easier. By the time I get home 30 miles from work it will spark knock even on a level city road if I lug it in overdrive and accelerate like passing a car. The funny thing is that if I stop and get gas it reverts back to normal on the drive home. No codes in PCM. I had a tech here at the Ford dealer I work for read my PCM. It says everything normal and the knock sensors are working. Any Ideas? |
sounds like you maxed out the MAF and burnt at least one plug...
so start with the plugs gapped for the additional boost, and if the issue persists, then swap out the COPS and time for a MAf upgrade and a TUNE |
Just swap out the COPs?? Don't even test them?? That's one expensive swap to do without confirming they are faulty. Besides, bad coils won't give spark knock. Spark knock (Detonation) happens when the compressed air/fuel mixture in the cylinder ignites from heat BEFORE the spark plug fires. Therefore it couldn't be a COP. It can destroy a normal motor quickly let alone a S/C motor. You most likely are having a lean condition, or too low octane fuel. Check for gaskets leaks all around the S/C and intake. Pretty much anything after the MAF sensor including vacuum hoses. I've read about the S/C'ed 5.4s having a vacuum line leak at an elbow behind everything out of sight.
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Oops old thread. My bad.
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Originally Posted by SwOkcOffRoader
(Post 14089770)
Oops old thread. My bad.
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Well gentleman now the air temp is back up so is my detonation. The problem may be I had the engine's thermostat changed a bit before this problem started. I had the aftermarket 160 taken out while the cooling system was flushed and a factory one installed. I figured either way the engine would reach the same running temp. What is your opinions? What brand stat and from whom do you guys buy yours?
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is your intercooler pump working??
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Originally Posted by STOFFERJ
(Post 14469706)
is your intercooler pump working??
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Hey guys I'd like to re-vive this thread since I never resolved the issue. Pump is working. Still no check engine light so no codes. The Service Dept here is no help since I have all the aftermarket stuff on it. Last time the plugs were changed 4 of them were fried. Pinhead didn't tell me which 4. Recently one of my Wholesale customers told me he thinks I got 4 "lazy" injectors. I went "things that make you say HMMMM". I know spark knock and fried plugs mean Too Lean. I kept wanting to blame knock sensor,Diablo, etc. Hadn't considered the fuel source. This makes sense ,kinda (lazy?), to me. So gentlemen, I'm asking your opinions. I am at work and don't have the time in between answering Wholesale Parts phones to use the search engine above or I would and research it myself. Thanks in advance.
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I am new to Lightnings but maybe a crank or cam sensor?
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Originally Posted by ChiefM
(Post 15106089)
I am new to Lightnings but maybe a crank or cam sensor?
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I'm leaning towards intake gasket leak, POSSIBLY a partially clogged fuel rail on one side. My only idea to try and figure out what cylinders are freaking out, is to get a temp gun and measure the exhaust manifold temps right by the cylinder ports. Do this right after it's freaking out bad. Hotter temps on certain cylinders will tell you which ones to look at.
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Originally Posted by SwOkcOffRoader
(Post 15111767)
I'm leaning towards intake gasket leak, POSSIBLY a partially clogged fuel rail on one side. My only idea to try and figure out what cylinders are freaking out, is to get a temp gun and measure the exhaust manifold temps right by the cylinder ports. Do this right after it's freaking out bad. Hotter temps on certain cylinders will tell you which ones to look at.
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I found this,
The oil treatment on K&N-type low-restriction filters has been known to collect on the wires of the MAF sensor, causing a malfunction. You might try Seafoam How to use SeaFoam to clean your Engine - The RIGHT way! which is safe and won't harm anything. I probably would just use it in the fuel where it works all the time. All this is assuming that carbon is actually the problem. It could also be a fault in the engine controls by allowing too much spark advance. In the old days we would get out the timing light and check the timing and adjust it at the distributor. I guess now they have to hook it up and do a diagnostic. Dealers and other shops now also do injection cleaning which is probably a good idea since you're having a severe problem. Premium fuel is good for this on a temporary basis because it reduces 'ping' and also has more cleaners. I would keep using it and put in a can of Sea-Foam with each fill of 15 gallons or more. If it doesn't get any better in the first few weeks, you probably should have the diagnostic done to see if there are any control or sensor problems. Most engines have a 'knock sensor' that could go bad and fail to send the signal to retard timing to prevent knock. |
Originally Posted by ChiefM
(Post 15118928)
I found this,
The oil treatment on K&N-type low-restriction filters has been known to collect on the wires of the MAF sensor, causing a malfunction. You might try Seafoam How to use SeaFoam to clean your Engine - The RIGHT way! which is safe and won't harm anything. I probably would just use it in the fuel where it works all the time. All this is assuming that carbon is actually the problem. It could also be a fault in the engine controls by allowing too much spark advance. In the old days we would get out the timing light and check the timing and adjust it at the distributor. I guess now they have to hook it up and do a diagnostic. Dealers and other shops now also do injection cleaning which is probably a good idea since you're having a severe problem. Premium fuel is good for this on a temporary basis because it reduces 'ping' and also has more cleaners. I would keep using it and put in a can of Sea-Foam with each fill of 15 gallons or more. If it doesn't get any better in the first few weeks, you probably should have the diagnostic done to see if there are any control or sensor problems. Most engines have a 'knock sensor' that could go bad and fail to send the signal to retard timing to prevent knock. |
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