Help - Weird sounds coming from inside the engine!!
Joined: Oct 2000
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From: WA
Originally posted by blackdemon
cdelena - I'm still not sure abt the engine oil, but if you read the European forum, there's this thread about this guy who broke his piston-conrod setup (with pictures). Presumably due to engine oil viscosity - he was not over-revving.
cdelena - I'm still not sure abt the engine oil, but if you read the European forum, there's this thread about this guy who broke his piston-conrod setup (with pictures). Presumably due to engine oil viscosity - he was not over-revving.
Let me again assure you that it is not an oil viscosity issue.
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Joined: Dec 2002
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From: Bandar Seri Begawan
cdelena - thx for that vote of 'reassurance' 
I was just brainstorming a while ago....and thought....could it be an ECU glitch? Have you heard anyone suffering from such problems? Is it advisable to do an ECU reset? I mean...since there's no visible mechanical damage (plus the fact that the knocking sound is intermittent), i'm now thinking that the ECU is retarding timing/ignition at some point in the VTEC phase.
Darn....i hate troubleshooting!!
I was just brainstorming a while ago....and thought....could it be an ECU glitch? Have you heard anyone suffering from such problems? Is it advisable to do an ECU reset? I mean...since there's no visible mechanical damage (plus the fact that the knocking sound is intermittent), i'm now thinking that the ECU is retarding timing/ignition at some point in the VTEC phase.
Darn....i hate troubleshooting!!
Joined: Mar 2001
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The valve adjustment interval is quite long - over 100,000 miles. But if they are noisey, they need to be adjusted at that time regardless of mileage.
That knocking sound upon throttle release from elevated rpm should be an indicator of what's going on. I'm sorry, but I'm not the one to know what that might be.
That knocking sound upon throttle release from elevated rpm should be an indicator of what's going on. I'm sorry, but I'm not the one to know what that might be.
Joined: Sep 2002
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From: Sydney
Hi,
I assume you have checked for missing throttle plate screws and eliminated valve train noise. Have you carried out a leakdown test on the cylinders? (more sensitive than a compression test)
Have you tried high RPM with the vtec oil soleniod disconnected?
If the noise is most apparent at high rpm when you lift of the throttle I would suggest that you remove the head and have a good look inside. Do this earlier rather than later as you may avoid an expensive blow up.
When you lift off the inlet vacuum is high ( ie lowest absolute pressure). On both the power and inlet stroke there is nothing pushing the piston back down the bore. If there is any stretch in the rod, rod bolts or cracks in the piston, thats when the piston is going to hit the head. Under power the inlet vacuum is near atmospheric ( 15 psi) and the engine is under power so there is something pushing the piston back down on both the inlet/power strokes. This takes up any slack and stops the piston hitting the head.
Good luck with it.
I assume you have checked for missing throttle plate screws and eliminated valve train noise. Have you carried out a leakdown test on the cylinders? (more sensitive than a compression test)
Have you tried high RPM with the vtec oil soleniod disconnected?
If the noise is most apparent at high rpm when you lift of the throttle I would suggest that you remove the head and have a good look inside. Do this earlier rather than later as you may avoid an expensive blow up.
When you lift off the inlet vacuum is high ( ie lowest absolute pressure). On both the power and inlet stroke there is nothing pushing the piston back down the bore. If there is any stretch in the rod, rod bolts or cracks in the piston, thats when the piston is going to hit the head. Under power the inlet vacuum is near atmospheric ( 15 psi) and the engine is under power so there is something pushing the piston back down on both the inlet/power strokes. This takes up any slack and stops the piston hitting the head.
Good luck with it.
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Joined: Mar 2002
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If the knocking were constant, I would be suspicious of valve clearance, but not if it is spiratic. I haven't ever had any injector problems, so I don't have any idea what they would be like, but it sounds logical that one of them could be the problem.
If there is a local shop with a dyno that measures Air / Fuel ratio, I would go for that. If the power drops off when the knocking starts, and the air / fuel ratio increases by 33%, I think that would be a good indicator.
If there is a local shop with a dyno that measures Air / Fuel ratio, I would go for that. If the power drops off when the knocking starts, and the air / fuel ratio increases by 33%, I think that would be a good indicator.
Joined: Aug 2002
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From: Mount Rainier
Originally posted by blackdemon
I was just brainstorming a while ago....and thought....could it be an ECU glitch? Have you heard anyone suffering from such problems? Is it advisable to do an ECU reset? I mean...since there's no visible mechanical damage (plus the fact that the knocking sound is intermittent), i'm now thinking that the ECU is retarding timing/ignition at some point in the VTEC phase.
Darn....i hate troubleshooting!!
I was just brainstorming a while ago....and thought....could it be an ECU glitch? Have you heard anyone suffering from such problems? Is it advisable to do an ECU reset? I mean...since there's no visible mechanical damage (plus the fact that the knocking sound is intermittent), i'm now thinking that the ECU is retarding timing/ignition at some point in the VTEC phase.
Darn....i hate troubleshooting!!
We only did a visual check and 'shake-n-rattle' check...haven't inspected the valves one-by-one.
The VTEC build-up (i.e. 5900 to 8300) is still there, but after throttle is released, that's when the knocking sound appears.
He's PULLING TEETH in Bandar Seri Begawan Brunei. ISTBH.
my .02
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Joined: Nov 2002
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From: Toronto
this might have already been addressed, but have you reduced your octane of fuel. poor octane can cause knocking or pinging sounds in the engine. And also as mentioned before, fuel system can be a big factor in small, annoying problems that never seem to go away. That is because most people overlook fuel system when diagnosing problems.
Joined: Mar 2001
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Originally posted by Benfica-S2000
this might have already been addressed, but have you reduced your octane of fuel. poor octane can cause knocking or pinging sounds in the engine. And also as mentioned before, fuel system can be a big factor in small, annoying problems that never seem to go away. That is because most people overlook fuel system when diagnosing problems.
this might have already been addressed, but have you reduced your octane of fuel. poor octane can cause knocking or pinging sounds in the engine. And also as mentioned before, fuel system can be a big factor in small, annoying problems that never seem to go away. That is because most people overlook fuel system when diagnosing problems.
Thread Starter
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Joined: Dec 2002
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From: Bandar Seri Begawan
Hi guys..
Sorry for the late update. Well, here's some late-breaking news: ECU was checked and guess what, the casing was badly corroded (??). Technician said it was due to the condensation from the air conditioning unit's blower (or something like that). the ECU was opened and seemed like there were some parts which was affected. Now waiting for the replacement parts...if that doesn't solve the problem, i might have to get a 2nd hand ECU from Japan.
There are only 5 S2Ks on the roads of Brunei, so right now i'm still looking for someone who's willing to 'borrow' their ECU for testing purposes (S2K owners here aren't exactly networked) - just to make sure that it's really the ECU which is causing the problem.
Engine scan reveals no error codes, apparently. Funny, huh?
All valves and springs has been physically checked - no cuts or fractures detected.
I haven't ruled out the possibility of the low octane problem. In Brunei, the unleaded fuel here goes at 97-Octane (that's the highest we get here in Brunei). What's really the recommended octane rating for the F20C? What octane rating do you get stateside? I heard that octane rating in Japan is between 103 to 107...wow.
So guys, whatever it is....wish me luck
Sorry for the late update. Well, here's some late-breaking news: ECU was checked and guess what, the casing was badly corroded (??). Technician said it was due to the condensation from the air conditioning unit's blower (or something like that). the ECU was opened and seemed like there were some parts which was affected. Now waiting for the replacement parts...if that doesn't solve the problem, i might have to get a 2nd hand ECU from Japan.
There are only 5 S2Ks on the roads of Brunei, so right now i'm still looking for someone who's willing to 'borrow' their ECU for testing purposes (S2K owners here aren't exactly networked) - just to make sure that it's really the ECU which is causing the problem.
Engine scan reveals no error codes, apparently. Funny, huh?
All valves and springs has been physically checked - no cuts or fractures detected.
I haven't ruled out the possibility of the low octane problem. In Brunei, the unleaded fuel here goes at 97-Octane (that's the highest we get here in Brunei). What's really the recommended octane rating for the F20C? What octane rating do you get stateside? I heard that octane rating in Japan is between 103 to 107...wow.
So guys, whatever it is....wish me luck