Classic Mustangs List Archive

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Mail From: David Kunz (email redacted)

Hey Gang,

I thought I'd play "stump the list" with this one.

When I bought my '65 coupe from my uncle (the original owner) 5 years
ago, he told me there was an occasional noise from the fuel pump once
the engine gets warm. He said that it had done this ever since the
timing chain was replaced at appox 110,000 miles. At the time I bought
the car, the engine had just over 120K on it. Now: about 142K.

The basics:

Stock 289 4-V A-code. Runs very strong, quiet, etc. Oil was changed
every 3K since new. Oil pressure gauge hooked up to engine (early '65
dash with warning light only) shows 55psi cold, 25-30 warm.

Sure enough, ever since I've owned the car, the fuel pump has made a
"knock, knock, knock" sound when the engine is idling when warm -- but
not all the time. Though my uncle told me he had replaced the fuel pump,
I replaced it again shortly after I got the car anyway. No help.

Recently, it started making the noise all the time. Perfectly quiet when
started up...fine on the way to the freeway...as soon as I exit the
freeway and the engine returns to idle, the noise is there.

My mechanics, who are very good at Fords and Mustangs, had heard other
small block Ford V-8s make a similar sound. Reluctanly, at my request,
they replaced the fuel pump with a new AC unit. The knock then actually
got worse. Becoming even more frustrated, I asked them to pull the
timing cover and have a look inside.

They did this, and found that the replacement timing chain had stretched
quite a bit. Also, the eccentric that drives the fuel pump (on the front
of the cam) was pretty chewed up. They installed a new chain and found a
good used eccentric. After all this, the noise is still there, as bad as
ever.

Tonight I spent about 10 minutes with a mechanic's stethoscope (as I've
done in the past with this) listening to *every* part of the engine, top
and bottom. The engine is remarkably quiet everywhere but the fuel pump,
where the metallic "knock, knock, knock" persists.

I'm at my wit's end...any thoughts would be most appreciated.

Dave Kunz
'65 coupe
'68 fastback (Bullitt replica)
'89 Merkur XR4Ti (hey, it's a Ford)

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This read-only message was archived from a public mail list.
Mail From: (email redacted) (email redacted)

I have the same symptoms and it is driving me BATS! I am "on the trail" of
this enigma and will let you know if I find it. Would ppreciate any news as
to what you may find. Wayne

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This read-only message was archived from a public mail list.
Mail From: Christopher T. Maher (email redacted)

David, my 68 289 has done that as long as I can remember and my friend's 66
convertible does the same thing. I always wondered what it was myself, I
have since resigned myself to the fact that it is a just a characteristic of
the 289 engine. If anyone comes up with a cure though I sure would be
interested.
BTW, mine did it before and after a complete rebuild.

Christopher Maher
1968 Hardtop
289 "C" code/ C4 auto
Highland Green/ Ivy gold

-----Original Message-----
From: David Kunz <(email redacted)>
To: (email redacted) <(email redacted)>
Date: Friday, June 18, 1999 1:57 AM
Subject: [CM:17409] 289 Fuel Pump Knock


>Hey Gang,
>
>I thought I'd play "stump the list" with this one.
>
>When I bought my '65 coupe from my uncle (the original owner) 5 years
>ago, he told me there was an occasional noise from the fuel pump once
>the engine gets warm. He said that it had done this ever since the
>timing chain was replaced at appox 110,000 miles. At the time I bought
>the car, the engine had just over 120K on it. Now: about 142K.
>
>The basics:
>
>Stock 289 4-V A-code. Runs very strong, quiet, etc. Oil was changed
>every 3K since new. Oil pressure gauge hooked up to engine (early '65
>dash with warning light only) shows 55psi cold, 25-30 warm.
>
>Sure enough, ever since I've owned the car, the fuel pump has made a
>"knock, knock, knock" sound when the engine is idling when warm -- but
>not all the time. Though my uncle told me he had replaced the fuel pump,
>I replaced it again shortly after I got the car anyway. No help.
>
>Recently, it started making the noise all the time. Perfectly quiet when
>started up...fine on the way to the freeway...as soon as I exit the
>freeway and the engine returns to idle, the noise is there.
>
>My mechanics, who are very good at Fords and Mustangs, had heard other
>small block Ford V-8s make a similar sound. Reluctanly, at my request,
>they replaced the fuel pump with a new AC unit. The knock then actually
>got worse. Becoming even more frustrated, I asked them to pull the
>timing cover and have a look inside.
>
>They did this, and found that the replacement timing chain had stretched
>quite a bit. Also, the eccentric that drives the fuel pump (on the front
>of the cam) was pretty chewed up. They installed a new chain and found a
>good used eccentric. After all this, the noise is still there, as bad as
>ever.
>
>Tonight I spent about 10 minutes with a mechanic's stethoscope (as I've
>done in the past with this) listening to *every* part of the engine, top
>and bottom. The engine is remarkably quiet everywhere but the fuel pump,
>where the metallic "knock, knock, knock" persists.
>
>I'm at my wit's end...any thoughts would be most appreciated.
>
>Dave Kunz
>'65 coupe
>'68 fastback (Bullitt replica)
>'89 Merkur XR4Ti (hey, it's a Ford)
>
>------------------------------------------------------------------------
>All the list info you'll ever want: antler.moose.to/~server/cm


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All the list info you'll ever want: antler.moose.to/~server/cm