Honda Car Forum

I know it's not a Mazda group, but it's a pretty bright lot in here, and
I doubt this issue is really Mazda-specific.

We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
'93 Protege, and while the new engine (well, used, from a wrecker) fired
right up and seems to run smoothly, there are some bad noises. One is a
steady clicking that appears to be one of the injectors. That one
doesn't worry us so much, but what does is the rattling/clanking sound
that SEEMS to be coming from the intake manifold and/or throttle body.
It almost sounds like something lose banging around, as it's steady in
time with the engine at idle, and starts after the engine starts to
warm, gets worse as it warms up, and seems to go away when we rev.

Everything bolted to the back of the engine seems tight and solid; there
doesn't appear to be any "outside" source of the noise. We're wondering
if it might be an intake valve and the noise is just travelling up the
manifold such that it seems to come from there.

Any other ideas of what to look at? Any help is appreciated...


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Built ford tough

"Matt Ion" <soundy@moltenimage.com> wrote in message
news:86Wdf.495786$oW2.406312@pd7tw1no...
>I know it's not a Mazda group, but it's a pretty bright lot in here, and I
>doubt this issue is really Mazda-specific.
>
> We just completed an engine swap (1.8l four, auto, EFI) in my buddy's '93
> Protege, and while the new engine (well, used, from a wrecker) fired right
> up and seems to run smoothly, there are some bad noises. One is a steady
> clicking that appears to be one of the injectors. That one doesn't worry
> us so much, but what does is the rattling/clanking sound that SEEMS to be
> coming from the intake manifold and/or throttle body. It almost sounds
> like something lose banging around, as it's steady in time with the engine
> at idle, and starts after the engine starts to warm, gets worse as it
> warms up, and seems to go away when we rev.
>
> Everything bolted to the back of the engine seems tight and solid; there
> doesn't appear to be any "outside" source of the noise. We're wondering
> if it might be an intake valve and the noise is just travelling up the
> manifold such that it seems to come from there.
>
> Any other ideas of what to look at? Any help is appreciated...
>
>
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>
>

> Jamco wrote:
> Built ford tough

>> I know it's not a Mazda group, but it's a pretty bright lot in here,
>> and I doubt this issue is really Mazda-specific.

>>> Some, perhaps.

Matt Ion wrote:
> I know it's not a Mazda group, but it's a pretty bright lot in here, and
> I doubt this issue is really Mazda-specific.
>
> We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
> '93 Protege, and while the new engine (well, used, from a wrecker) fired
> right up and seems to run smoothly, there are some bad noises. One is a
> steady clicking that appears to be one of the injectors. That one
> doesn't worry us so much, but what does is the rattling/clanking sound
> that SEEMS to be coming from the intake manifold and/or throttle body.
> It almost sounds like something lose banging around, as it's steady in
> time with the engine at idle, and starts after the engine starts to
> warm, gets worse as it warms up, and seems to go away when we rev.
>
> Everything bolted to the back of the engine seems tight and solid; there
> doesn't appear to be any "outside" source of the noise. We're wondering
> if it might be an intake valve and the noise is just travelling up the
> manifold such that it seems to come from there.
>
> Any other ideas of what to look at? Any help is appreciated...
>

I'd really post this in the mazda group. It is most likely a well known
problem.

Might be a heat shield or something like that. Sound travel can fool
you.
Get a fishing pole (or actually any thing stick), putting one end on
potentially offending parts. Make a fist around the other side of the
stick and put your fist to your ear - this makes a poor man's
stethoscope.
You might be able to find it this way.

--or--

Mazdas have decent stereos, right? Just turn it up


Remco

Remco wrote:
> Matt Ion wrote:
>
>>I know it's not a Mazda group, but it's a pretty bright lot in here, and
>>I doubt this issue is really Mazda-specific.
>>
>>We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
>>'93 Protege, and while the new engine (well, used, from a wrecker) fired
>>right up and seems to run smoothly, there are some bad noises. One is a
>>steady clicking that appears to be one of the injectors. That one
>>doesn't worry us so much, but what does is the rattling/clanking sound
>>that SEEMS to be coming from the intake manifold and/or throttle body.
>>It almost sounds like something lose banging around, as it's steady in
>>time with the engine at idle, and starts after the engine starts to
>>warm, gets worse as it warms up, and seems to go away when we rev.
>>
>>Everything bolted to the back of the engine seems tight and solid; there
>>doesn't appear to be any "outside" source of the noise. We're wondering
>>if it might be an intake valve and the noise is just travelling up the
>>manifold such that it seems to come from there.
>>
>>Any other ideas of what to look at? Any help is appreciated...
>>
>
>
> I'd really post this in the mazda group. It is most likely a well known
> problem.

The only Mazda group my server seems to carry is rec.autos.makers.mazda;
I did post there, but there appears to be almost no traffic.

> Might be a heat shield or something like that. Sound travel can fool
> you.

There is no heat shield, we didn't put it back on.

> Mazdas have decent stereos, right? Just turn it up

This is a Very Bad Noise. Something is wrong and masking it won't help.


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Matt Ion wrote:
> Remco wrote:
> > Matt Ion wrote:
> >
> >>I know it's not a Mazda group, but it's a pretty bright lot in here, and
> >>I doubt this issue is really Mazda-specific.
> >>
> >>We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
> >>'93 Protege, and while the new engine (well, used, from a wrecker) fired
> >>right up and seems to run smoothly, there are some bad noises. One is a
> >>steady clicking that appears to be one of the injectors. That one
> >>doesn't worry us so much, but what does is the rattling/clanking sound
> >>that SEEMS to be coming from the intake manifold and/or throttle body.
> >>It almost sounds like something lose banging around, as it's steady in
> >>time with the engine at idle, and starts after the engine starts to
> >>warm, gets worse as it warms up, and seems to go away when we rev.
> >>
> >>Everything bolted to the back of the engine seems tight and solid; there
> >>doesn't appear to be any "outside" source of the noise. We're wondering
> >>if it might be an intake valve and the noise is just travelling up the
> >>manifold such that it seems to come from there.
> >>
> >>Any other ideas of what to look at? Any help is appreciated...
> >>
> >
> >
> > I'd really post this in the mazda group. It is most likely a well known
> > problem.
>
> The only Mazda group my server seems to carry is rec.autos.makers.mazda;
> I did post there, but there appears to be almost no traffic.
>
> > Might be a heat shield or something like that. Sound travel can fool
> > you.
>
> There is no heat shield, we didn't put it back on.
>
> > Mazdas have decent stereos, right? Just turn it up
>
> This is a Very Bad Noise. Something is wrong and masking it won't help.
>

I've not worked very much on Mazdas but see if it has an exhaust system
where the pipe is dual sleeved -- basically a muffler inside another
pipe.
They tend to resonate at very specfic frequencies when the inner pipe's
mounting breaks and rattles against the outer pipe.

My wife's acura made awful noise around 1200 rpm when cold -- found it
was coming from the pipe going from the engine to the cat. A fix
(besides replacing it) is to carefully cut the outer pipe and reweld
the connection from the outside to the inside.

Remco

> > Matt Ion wrote:
> >
> >>I know it's not a Mazda group, but it's a pretty bright lot in here, and
> >>I doubt this issue is really Mazda-specific.
> >>
> >>We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
> >>'93 Protege, and while the new engine (well, used, from a wrecker) fired
> >>right up and seems to run smoothly, there are some bad noises. One is a
> >>steady clicking that appears to be one of the injectors.

You sound like a guy with a lot of auto repair experience and so you
probably already checked, so for my own and other amateurs' edification, and
just to eliminate it: Have you checked the valve lash? Too wide a gap will
cause clicking.

If it's in spec but on the wide side, then the clicking is supposed to go
away after warmup.

Elle wrote:
>>>Matt Ion wrote:
>>>
>>>
>>>>I know it's not a Mazda group, but it's a pretty bright lot in here, and
>>>>I doubt this issue is really Mazda-specific.
>>>>
>>>>We just completed an engine swap (1.8l four, auto, EFI) in my buddy's
>>>>'93 Protege, and while the new engine (well, used, from a wrecker) fired
>>>>right up and seems to run smoothly, there are some bad noises. One is a
>>>>steady clicking that appears to be one of the injectors.
>
>
> You sound like a guy with a lot of auto repair experience and so you

Thank you I'm not a professional mechanic, but I do have a fair bit
of experience, particularly with 4-banger rice burners We all have
the occaisional brain fart (especially after three days working in an
unheated carport to do this engine swap), which is why I posted this in
the first place - sometimes it just takes a fresh brain to look at a
problem.

> probably already checked, so for my own and other amateurs' edification, and
> just to eliminate it: Have you checked the valve lash? Too wide a gap will
> cause clicking.

We (myself and another experienced mechanic who also worked on the swap)
had considered that, but the location and type of noise didn't seem to
fit. A broken valve spring was also suggested. Frankly, I'm all for
checking these things, but unfortunately didn't have enough time to do
it myself, and the other guy doesn't seem to want to bother.

The idea does seem to fit though, by my thinking - the noise appears to
be coming from the throttle body or intake manifold, which could well
correspond to a noisy intake valve, echoing back up the intake.

> If it's in spec but on the wide side, then the clicking is supposed to go
> away after warmup.

It hasn't run long enough to warm up yet - the noise gets louder and
worse within the first 60 seconds of running, and we shut it down to
avoid any potential damage (this is a REALLY scary kind of noise to be
coming from an engine).

Thanks for the diagnosis (so refreshing to have an intelligent
converation on this, instead of the usual snide retorts). I'll make sure
one of us does look under the valve cover.


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