Exhaust whistle and rough idling when cold

Archives of Posts to the NZ MX5 List back in 2006
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kiwipete
Tentative sideways sliding....
Tentative sideways sliding....
Posts: 49
Joined: Sat May 20, 2006 6:38 pm
Location: Glendowie, Auckland

Exhaust whistle and rough idling when cold

Post by kiwipete » Tue May 02, 2006 12:34 am

Hey there.

When starting from cold, my '89 120k idles very roughly sometimes
stalling... plug lead perhaps or carbon? Also when accelerating the exhaust
whistles... seems worst under load. I reckon it's after market system and
would guess cat converter removed... any ideas?

regards.. kiwipete from Akl
kiwipete
89 MX5
Plus 99 MX5 owned by my darling!
Plus 15 motorcycles of various makes.

MadMaz
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Thu May 18, 2006 10:56 pm
Location: Pukekohe

Exhaust whistle and rough idling when cold

Post by MadMaz » Tue May 02, 2006 9:38 am

Gidday kiwipete

I'd go right through the following checklist & approach:

If your car's done 120k's, replace the plug leads and replace the plugs
if over 15,000k old. The distributor cap might also need replacing if the
alloy posts inside are significantly corroded or there are signs of
electrical "tracking marks". (Hey also make sure the cam belt has been
replaced - unbolt the top cover and a quick visual check will tell the story
straight away. If shiny in appearance - replace!!).

Tank right up with 98 octane fuel and a full bottle of petrol injector
cleaner. Replace the engine oil with a semi synthetic grade or fully
synthetic & replace the oil filter if both more than 7,000 k's old, air
filter if over 20,000 k's old. Take to a tune shop and do the 14 Deg advance
and have the idle bleed screw adjusted for a smooth idle with a warm engine.

At 120k, it's 95% likely the above will solve your problems. Low compression
is not very likely at those k's, unless the car has been very poorly
maintained, nor a faulty ECU likely unless someone has
used ordinary jumper leads without resistors to start another car.

The whistle is caused by resonance present somewhere in the
exhaust system - sometimes caused by the exhaust gases passing over the
holes in the perforated inner tube of worn out resonators - like air can be
made to whistle by blowing over the holes of a flute for example.

I'd go to an exhaust shop, haul the car up on the lift and get a thorough
check done of the exhaust system. If the cat's still there, definitely
remove it if the car's done 120k and put a new resonator in it's place.
Check the condition of the existing rear muffler and of the resonator if
fitted (some cars don't have them).

After all this, go for a long drive periodically slowing down, selecting
second gear and taking it to the redline (on a quiet section of 100k open
road) several times. It's well known that Jap engines, especially
performance DOHC's, like to be driven hard every now and again to "clear the
throat", especially if used regularly in the suburbs.

You'll be surprised at how much better the car will accelerate with better
torque down low and maintain a steady 100k cruise with a surprisingly light
right foot - along with easy starting, smooth idling and better mpg's!

Cheers
Mark
(Firm Believer in 98 Go Juice - Go For It!).

From sklauss@teamnissan.co.nz Fri Apr 27 17:58:08 2007
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Subject: F/I day
Date: Tue, 2 May 2006 10:56:58 +1200
Thread-Topic: F/I day
Thread-Index: AcZtco0lDpswC8QvRq+3QcKCWAn1qg==
From: "Stefan Klauss" <sklauss@teamnissan.co.nz>
To: <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <9O5rCC.A.USH.bGZMGB@L733>

Would be right out interested. Let us know where and when it would be
planed for.

Cheers

Stefan Klauss


Email: sklauss@teamnissan.co.nz


DISCLAIMER:

This message may contain confidential information that is legally
privileged and is intended only for the use of the parties to whom it is
addressed. If you are not an intended recipient, you are hereby notified
that any disclosure, copying, distribution, or use of any information in
this message is strictly prohibited. If you have received this message
in error, please notify the sender immediately and delete the message.
Thank you
Firm Believer in 98 Go Juice - Go for it!

MadMaz
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 100
Joined: Thu May 18, 2006 10:56 pm
Location: Pukekohe

Exhaust whistle and rough idling when cold

Post by MadMaz » Tue May 02, 2006 9:38 am

Gidday kiwipete

I'd go right through the following checklist & approach:

If your car's done 120k's, replace the plug leads and replace the plugs
if over 15,000k old. The distributor cap might also need replacing if the
alloy posts inside are significantly corroded or there are signs of
electrical "tracking marks". (Hey also make sure the cam belt has been
replaced - unbolt the top cover and a quick visual check will tell the story
straight away. If shiny in appearance - replace!!).

Tank right up with 98 octane fuel and a full bottle of petrol injector
cleaner. Replace the engine oil with a semi synthetic grade or fully
synthetic & replace the oil filter if both more than 7,000 k's old, air
filter if over 20,000 k's old. Take to a tune shop and do the 14 Deg advance
and have the idle bleed screw adjusted for a smooth idle with a warm engine.

At 120k, it's 95% likely the above will solve your problems. Low compression
is not very likely at those k's, unless the car has been very poorly
maintained, nor a faulty ECU likely unless someone has
used ordinary jumper leads without resistors to start another car.

The whistle is caused by resonance present somewhere in the
exhaust system - sometimes caused by the exhaust gases passing over the
holes in the perforated inner tube of worn out resonators - like air can be
made to whistle by blowing over the holes of a flute for example.

I'd go to an exhaust shop, haul the car up on the lift and get a thorough
check done of the exhaust system. If the cat's still there, definitely
remove it if the car's done 120k and put a new resonator in it's place.
Check the condition of the existing rear muffler and of the resonator if
fitted (some cars don't have them).

After all this, go for a long drive periodically slowing down, selecting
second gear and taking it to the redline (on a quiet section of 100k open
road) several times. It's well known that Jap engines, especially
performance DOHC's, like to be driven hard every now and again to "clear the
throat", especially if used regularly in the suburbs.

You'll be surprised at how much better the car will accelerate with better
torque down low and maintain a steady 100k cruise with a surprisingly light
right foot - along with easy starting, smooth idling and better mpg's!

Cheers
Mark
(Firm Believer in 98 Go Juice - Go For It!).

From sklauss@teamnissan.co.nz Fri Apr 27 17:58:08 2007
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Subject: F/I day
Date: Tue, 2 May 2006 10:56:58 +1200
Thread-Topic: F/I day
Thread-Index: AcZtco0lDpswC8QvRq+3QcKCWAn1qg==
From: "Stefan Klauss" <sklauss@teamnissan.co.nz>
To: <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <9O5rCC.A.USH.bGZMGB@L733>

Would be right out interested. Let us know where and when it would be
planed for.

Cheers

Stefan Klauss


Email: sklauss@teamnissan.co.nz


DISCLAIMER:

This message may contain confidential information that is legally
privileged and is intended only for the use of the parties to whom it is
addressed. If you are not an intended recipient, you are hereby notified
that any disclosure, copying, distribution, or use of any information in
this message is strictly prohibited. If you have received this message
in error, please notify the sender immediately and delete the message.
Thank you
Firm Believer in 98 Go Juice - Go for it!

joanie
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 109
Joined: Fri May 19, 2006 3:48 pm
Location: Paekakariki

Exhaust whistle and rough idling when cold

Post by joanie » Tue May 02, 2006 11:09 am

After all this, go for a long drive periodically slowing down, selecting
second gear and taking it to the redline (on a quiet section of 100k open
road) several times. It's well known that Jap engines, especially
performance DOHC's, like to be driven hard every now and again to "clear the
throat", especially if used regularly in the suburbs.


Actually I believe its known as an Italian tune-up :-)
Joan H

From chris.tankard@aderant.com Fri Apr 27 17:58:09 2007
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Subject: RE: F/I day
Date: Tue, 2 May 2006 11:09:27 +1200
Thread-Topic: F/I day
Thread-Index: AcZtco0lDpswC8QvRq+3QcKCWAn1qgAAb5eN
References: <232964E37F858D4395B01BD7AE8FAF3E23D8C8@tnserver01.teamnissan.co.nz>
From: "Chris Tankard" <chris.tankard@aderant.com>
To: "MX5List" <mx5list@mx5club.org.nz>, <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <JPvit.A.WSH.bGZMGB@L733>

In regard to timing I am looking ar approx 6 weekends away.

Stefan - you're on the list.

C

________________________________

From: e-admin@mx5club.org.nz on behalf of Stefan Klauss
Sent: Tue 2/05/2006 10:56 AM
To: mx5list@mx5club.org.nz
Subject: F/I day


Would be right out interested. Let us know where and when it would be planed
for.

Cheers

Stefan Klauss


Email: sklauss@teamnissan.co.nz


DISCLAIMER:

This message may contain confidential information that is legally privileged
and is intended only for the use of the parties to whom it is addressed. If
you are not an intended recipient, you are hereby notified that any
disclosure, copying, distribution, or use of any information in this message
is strictly prohibited. If you have received this message in error, please
notify the sender immediately and delete the message. Thank you


________________________
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joanie
Need, more, 5-ing, time....
Need, more, 5-ing, time....
Posts: 109
Joined: Fri May 19, 2006 3:48 pm
Location: Paekakariki

Exhaust whistle and rough idling when cold

Post by joanie » Tue May 02, 2006 11:09 am

After all this, go for a long drive periodically slowing down, selecting
second gear and taking it to the redline (on a quiet section of 100k open
road) several times. It's well known that Jap engines, especially
performance DOHC's, like to be driven hard every now and again to "clear the
throat", especially if used regularly in the suburbs.


Actually I believe its known as an Italian tune-up :-)
Joan H

From chris.tankard@aderant.com Fri Apr 27 17:58:09 2007
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Subject: RE: F/I day
Date: Tue, 2 May 2006 11:09:27 +1200
Thread-Topic: F/I day
Thread-Index: AcZtco0lDpswC8QvRq+3QcKCWAn1qgAAb5eN
References: <232964E37F858D4395B01BD7AE8FAF3E23D8C8@tnserver01.teamnissan.co.nz>
From: "Chris Tankard" <chris.tankard@aderant.com>
To: "MX5List" <mx5list@mx5club.org.nz>, <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <JPvit.A.WSH.bGZMGB@L733>

In regard to timing I am looking ar approx 6 weekends away.

Stefan - you're on the list.

C

________________________________

From: e-admin@mx5club.org.nz on behalf of Stefan Klauss
Sent: Tue 2/05/2006 10:56 AM
To: mx5list@mx5club.org.nz
Subject: F/I day


Would be right out interested. Let us know where and when it would be planed
for.

Cheers

Stefan Klauss


Email: sklauss@teamnissan.co.nz


DISCLAIMER:

This message may contain confidential information that is legally privileged
and is intended only for the use of the parties to whom it is addressed. If
you are not an intended recipient, you are hereby notified that any
disclosure, copying, distribution, or use of any information in this message
is strictly prohibited. If you have received this message in error, please
notify the sender immediately and delete the message. Thank you


________________________
Visit http://www.aderant.com for information on products and services.
Visit https://support.aderant.com for information on support.

kiwipete
Tentative sideways sliding....
Tentative sideways sliding....
Posts: 49
Joined: Sat May 20, 2006 6:38 pm
Location: Glendowie, Auckland

Exhaust whistle and rough idling when cold

Post by kiwipete » Tue May 02, 2006 4:08 pm

Thanks so much for suestions... will do and report back. Appreciate the
assistance.

kiwipete

From petergarrity@gmail.com Fri Apr 27 17:58:10 2007
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Date: Tue, 2 May 2006 16:31:02 +1200
From: "Peter Garrity" <petergarrity@gmail.com>
To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: Exhaust whistle and rough idling when cold
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Hi Mark,
it was interesting to read your post for our 1996 NA is approaching 120km. I
was asking at the Mazda dealer in Wellington (this was some time ago) about
advancing the timing to 14, and he talked me out of it. His argument was
that you use up much more fuel. I was wondering what you, or anyone else has
to say about that, and if you had any comments on the difference in
performance.
Cheers,
Peter

On 5/2/06, Mark O'Sullivan <mark.os@slingshot.co.nz> wrote:
[...]
kiwipete
89 MX5
Plus 99 MX5 owned by my darling!
Plus 15 motorcycles of various makes.

Okibi
See my 5 and raise you.
See my 5 and raise you.
Posts: 94
Joined: Fri May 19, 2006 2:03 am

Exhaust whistle and rough idling when cold

Post by Okibi » Tue May 02, 2006 8:06 pm

The exhaust "whistle" and rough idle COULD be a loose pipe from your rocket
cover breather to the intake runner (from the AFM to the Throttle Body) .


It could also be related to the valve from the other side of the rocker
cover to the intake manifold.


- Dave.
If you had access to a car like this, would you take it back right away? Neither would I.

Okibi
See my 5 and raise you.
See my 5 and raise you.
Posts: 94
Joined: Fri May 19, 2006 2:03 am

Exhaust whistle and rough idling when cold

Post by Okibi » Tue May 02, 2006 8:06 pm

The exhaust "whistle" and rough idle COULD be a loose pipe from your rocket
cover breather to the intake runner (from the AFM to the Throttle Body) .


It could also be related to the valve from the other side of the rocker
cover to the intake manifold.


- Dave.
If you had access to a car like this, would you take it back right away? Neither would I.

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