Miatapower List Archive

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





All,

Has anyone experienced this or maybe have some ideas.

When I start my car - it sounds just fine. A nice quiet hum. Even when I rev
it a little bit - still a happy hum.

When I first drive it though and bring the boost gauge up to about 10 in HG
vacuum - I hear this really throaty sound, repetitive sound ( almost like
knocking - eeks ). But it sounds more like an exhaust leak ( I had my Dad in
the car today for a second opinion - he thought it was an exhaust leak too ).
But after about 3-4 minutes of driving - it's gone. Like the cold metal
expanded a bit and sealed somewhere - WAG.

I think the sound is getting a little worse - it might have been what I though
was engine clatter earlier ( when I was running 5w30 weight oil - just changed
to 10w40 today ) or even the HLA's a couple of weeks ago ( when I switched to
5w30 oil ... ).

I've had the cat off a couple of times - replacing between that and a test pipe.
Put in new gaskets. So I don't think that's it. Plus it sounds like it's
coming from the hood - not from under the car.

It's hot right now, so I'm not going to touch it - but maybe the exhaust
manifold bolts or downpipe bolts off the turbo.

Any ideas, please let me know.

Thanks,

Dan

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


Dan, I had a similar noise recently - turned out that two of the bolts
holding my Greddy/Mitsubishi turbo had broken, and exhaust gas was escaping
under load (not necessarily boost, but partial throttle as well). I was
puzzled, since I could not feel a leak at idle - however, once the gasket
burned out, I could feel a leak alright. Once I had the manifold off I
found that it was cracked around the turbo mounting flange. Before all
this, my downpipe cracked and had to be replaced. I guess it never rains
but it pours.

So, it may be your downpipe, a broken bolt/stud or two, or a cracked
manifold. Sounds just like an exhaust leak, anyway. Good luck tracking it
down, and I hope it's not too expen$ive.

Steven Searle


----- Original Message -----
From: <(email redacted)>
To: <(email redacted)>
Sent: Sunday, July 04, 1999 3:51 PM
Subject: Start up noise diagnosis


> All,
>
> Has anyone experienced this or maybe have some ideas.
>
> When I start my car - it sounds just fine. A nice quiet hum. Even when I
rev
> it a little bit - still a happy hum.
>
> When I first drive it though and bring the boost gauge up to about 10 in
HG
> vacuum - I hear this really throaty sound, repetitive sound ( almost like
> knocking - eeks ). But it sounds more like an exhaust leak ( I had my Dad
in
> the car today for a second opinion - he thought it was an exhaust leak
too ).
> But after about 3-4 minutes of driving - it's gone. Like the cold metal
> expanded a bit and sealed somewhere - WAG.
>
> I think the sound is getting a little worse - it might have been what I
though
> was engine clatter earlier ( when I was running 5w30 weight oil - just
changed
> to 10w40 today ) or even the HLA's a couple of weeks ago ( when I switched
to
> 5w30 oil ... ).
>
> I've had the cat off a couple of times - replacing between that and a test
pipe.
> Put in new gaskets. So I don't think that's it. Plus it sounds like it's
> coming from the hood - not from under the car.
>
> It's hot right now, so I'm not going to touch it - but maybe the exhaust
> manifold bolts or downpipe bolts off the turbo.
>
> Any ideas, please let me know.
>
> Thanks,
>
> Dan
>
>

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


Check your EGR pipe connection at the manifold - not easy to get to and
harder to diagnose. It had my 2 resident experts stumped, then the brass
adapter vaporized and the problem became obvious.

Mel
------------------------------------------------------------
Mel Hoagland ((email redacted))
"Wheezy" black 96 FMII (vrrooommmm?)

-----Original Message-----
From: (email redacted) <(email redacted)>
To: (email redacted) <(email redacted)>
Date: Sunday, July 04, 1999 6:15 PM
Subject: Start up noise diagnosis


>
>
>
>
>All,
>
>Has anyone experienced this or maybe have some ideas.
>
>When I start my car - it sounds just fine. A nice quiet hum. Even when I
rev
>it a little bit - still a happy hum.
>
>When I first drive it though and bring the boost gauge up to about 10 in HG
>vacuum - I hear this really throaty sound, repetitive sound ( almost like
>knocking - eeks ). But it sounds more like an exhaust leak ( I had my Dad
in
>the car today for a second opinion - he thought it was an exhaust leak
too ).
>But after about 3-4 minutes of driving - it's gone. Like the cold metal
>expanded a bit and sealed somewhere - WAG.
>
>I think the sound is getting a little worse - it might have been what I
though
>was engine clatter earlier ( when I was running 5w30 weight oil - just
changed
>to 10w40 today ) or even the HLA's a couple of weeks ago ( when I switched
to
>5w30 oil ... ).
>
>I've had the cat off a couple of times - replacing between that and a test
pipe.
>Put in new gaskets. So I don't think that's it. Plus it sounds like it's
>coming from the hood - not from under the car.
>
>It's hot right now, so I'm not going to touch it - but maybe the exhaust
>manifold bolts or downpipe bolts off the turbo.
>
>Any ideas, please let me know.
>
>Thanks,
>
>Dan
>
>

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


My header bolts (allen head) had been loosening up. I understand this is not
uncommon. Corky says put a star "lock" washer in. Worked so far.

Mark S. Allen
Angleton TX

(email redacted) wrote:

> All,
>
> Has anyone experienced this or maybe have some ideas.
>
> When I start my car - it sounds just fine. A nice quiet hum. Even when I rev
> it a little bit - still a happy hum.
>
> When I first drive it though and bring the boost gauge up to about 10 in HG
> vacuum - I hear this really throaty sound, repetitive sound ( almost like
> knocking - eeks ). But it sounds more like an exhaust leak ( I had my Dad in
> the car today for a second opinion - he thought it was an exhaust leak too ).
> But after about 3-4 minutes of driving - it's gone. Like the cold metal
> expanded a bit and sealed somewhere - WAG.
>
> I think the sound is getting a little worse - it might have been what I though
> was engine clatter earlier ( when I was running 5w30 weight oil - just changed
> to 10w40 today ) or even the HLA's a couple of weeks ago ( when I switched to
> 5w30 oil ... ).
>
> I've had the cat off a couple of times - replacing between that and a test pipe.
> Put in new gaskets. So I don't think that's it. Plus it sounds like it's
> coming from the hood - not from under the car.
>
> It's hot right now, so I'm not going to touch it - but maybe the exhaust
> manifold bolts or downpipe bolts off the turbo.
>
> Any ideas, please let me know.
>
> Thanks,
>
> Dan