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Hey guys,
i currently own and drive a 1999 accord 4-cylinder automatic. It has 187,000 original miles on the original f23a4 engine and maxa trans.
My cars engine makes a rather weird humming/ticking noise around idle, but only when cold. Once the engine is up to operating temp ( usually within 1/2 mile or so), its very quiet, no noise to be heard at all like this.
If I rev the engine up by hand with the hood open (while cold), the noise fades away as the rpm rise, but when I let it idle down the noise comes back again for a brief moment. Only around that certain rpm range when cold it makes the noise. This car has had oil changes every 3-4k miles for the past 30k miles that I have owned it, and I have some records that indicate the previous owner did the same. My buddy and I adjusted the valves a few oil changes ago, and he said the insides of my engine are VERY clean for its age, and he knows cars much better then I do.
I used a stethoscope to feel around when the engine is cold, and its definitely coming from around the intake manifold area. I couldnt exactly pin point it, but i know its not any of the accessories/belts/pulleys.
I went ahead and googled “honda engine noise”, and found a youtube video that (surprisingly) displays the almost the exact same noise that my car makes:The ticking noise is much more noticeable on my car then in this video, but for the most part the noise sounds close to my car when cold. Other then this noise, it runs exceptionally well and has good power everywhere for what it is.
Im hoping that maybe someone on this forum would know or recognize this noise. I know that a very small tick can make a huge noise, I learned that from bad sway bar bushings. 🙂
Thanks,
Andrew
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You may need a valve adjustment.
https://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car
I checked the valves yesterday, only 5 valves needed adjustment. I looked around, all the cam lobes look fine. I replaced the valve cover gasket (for the 4th time) and I changed my oil. Im trying rotella t6 5w-40. I was running valvoline synthetic high mileage 5w-30. Only had 2,400 on the oil, so I left the filter. I haven’t run the car yet today, as Im going to replace the input speed sensor in my friends 01 maxima first.
To my knowledge, Shell Rotella T6 is rated for use in heavy duty diesel engines. I’m not sure it’s even certified for spark ignition/gasoline engine use. While being an excellent lubricant in the proper application, you might be running an oil which doesn’t have an additive package appropriate for your requirements.
Update:
I have since adjusted my valves and switched my oil to a 10w-30 synthetic-blend oil and a new bosch oil filter. I checked the timing belt tension while I had the valve cover off, and the belt is still pretty darn tight and everything else looks fine.
The noise is relatively faint now, and really only audible with the windows down, and on deceleration (cold obviously). I live on a hill, and drive down it every morning for work, which is when I hear the noise mostly, after the first 1/4 mile, I don’t hear it much. The car is quiet like a mouse once warmed up to operating temp, which is usually within a mile of home. I have a scan-gauge so I can watch the water temp rise and the noise fade.
I am beginning to think its either piston-slap or something with the transmission (which is original to the car); either of which is to be expected from high-mileage Honda’s of this vintage. Either way I’m just going to drive the wheels off this car.Okay, so this may sound weird.
I have a scangauge OBD2 digital readout on this car. I got curious, so I set it to “IGN”, or ignition timing.
With the car somewhat cold, I fired it up. The timing sits at around 9-10* at idle (~1000rpm when cold), and when I rev the engine up to about 2k-2.5k rpms, timing goes up to about 15-17* on throttle, but when I let off the throttle, the knocking noise is present and timing jumps to 35*. Im going to monitor the timing the best I can tomorrow on my way to work, and see if there is still a relation between the two.
Although, I am trying to figure out why the ECU would throw so much timing at the engine when cold. Maybe one of you guys on here would know, but this leads leads me to think that maybe the noise is actual pre-ignition/pinging/knocking.
Im considering getting a new knock sensor and o2 sensors. I recently replaced the ignition rotor, coil and dist cap a few months ago. I still have the original coil, so I can try to put the old one back in and try it.
I already have new NGK spark plug wires in the mail, since some sort of vermin decided to naw a bit out on one of the wires 😆 .
EDIT: this car has the ULEV f23a4 motor, and its a J vin code, so it was built in Japan.
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