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| Engine Noise (Page 1/3) |
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nero
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MAY 01, 08:56 PM
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Hello, one issue figured out but now a different issue to figure out.
Its an 87 Gt 2.8L that I am trying to get back on the road after almost 3 years. It starts up with no issues but it just does not sound good. No smoking out of the exhaust and the idle is pretty smooth (cold fast idle in the video). I thought is may have been an exhaust leak / manifold leak but I could not find any exhaust leaks at the manifold or anywhere else. But it does not sound great, some type of ticking or missing sound. Below is a link to a quick video, any thoughts in what to check? I checked the firing order, all the exhaust connections. Also, when revving it up, it will pop out the exhaust. I did do a bit of work to it over the years such as replacing the ECM, replaced exhaust, plugs and wires, brakes lines, clutch lines...etc, but no major mechanical engine work as it drove fine, when I drove it home (1.5 hour drive) prior to fixing it up over the pas few years.
Any thoughts as to where to start looking for the cause of the engine sound?
[This message has been edited by nero (edited 05-01-2022).]
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IMSA GT
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MAY 01, 09:27 PM
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Before we even start, is that your idle speed or is someone in the car pressing the gas pedal?
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nero
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MAY 01, 09:39 PM
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| quote | Originally posted by IMSA GT:
Before we even start, is that your idle speed or is someone in the car pressing the gas pedal? |
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Hello IMSA GT, thanks for the reply. Its the cold idle. Just started up. It's still 'cool' up here in Canada (about 8-10C today). Once it runs for about 5 min it idles down to 650-700 or so. The cold idle was somewhere around1500-1750.[This message has been edited by nero (edited 05-01-2022).]
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Skybax
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MAY 01, 09:50 PM
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You need to use a piece of heater hose 2 to 3 foot long and hold one end to your ear, use it like a stethoscope, moving other end around to different areas on the engine to narrow in on the sound.
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Patrick
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MAY 01, 10:20 PM
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Difficult to tell from a video, but it sounds to me like an exhaust leak.
Check to make sure that all exhaust manifold bolts are actually in place.
I wouldn't be surprised if you discover that the forward exhaust manifold is cracked.
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hunter29
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MAY 01, 10:24 PM
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Does it go away when it warms up?
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nero
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MAY 01, 10:27 PM
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| quote | Originally posted by Skybax:
You need to use a piece of heater hose 2 to 3 foot long and hold one end to your ear, use it like a stethoscope, moving other end around to different areas on the engine to narrow in on the sound. |
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Thanks for the tip, I will give that a try.
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nero
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MAY 01, 10:33 PM
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| quote | Originally posted by Patrick:
Difficult to tell from a video, but it sounds to me like an exhaust leak.
Check to make sure that all exhaust manifold bolts are actually in place.
I wouldn't be surprised if you discover that the forward exhaust manifold is cracked. |
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Hello Patrick, that is what I have been leaning towards as the issue but I can't track down any leaks. All the manifold bolts are there and they both look solid with along with the gasket. For sure I could have missed something, so I will check it out again. The forward facing one it hard to get a great look at but I have looked from below and above and I can't see any issues.
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hunter29
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MAY 01, 10:35 PM
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You can also use a piece of 2x2 wood , a hammer, anything that will transmit the sound to your ear.
This works good for listening to the inside of the engine.
Example, lay your wood stick on the valve cover, put the other end to your ear,
Never tried the heater hose,
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nero
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MAY 01, 10:35 PM
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| quote | Originally posted by hunter29:
Does it go away when it warms up? |
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Unfortunately it does not, same type of noise when it is warmed up.
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