warm up problems

[Brian and Lyn Hood]

Our 1990 MX5 starts easily, but the revs drop from about 1250 to 1000
immediately after starting. Car then runs rough for the first 0.5km and
stalls at the 1st intersection. Once warmed up it runs beautifully. Runs
at about 500-600 revs. Petrol consumption is down dramatically. Was about
25-26, now 17-18MPG.

Have changed the spark plug leads, put in two lots of injection cleaner and
had it professionally tuned at a local garage.

Comments or suggestions please!

Brian Hood
Ph (09) 629 0338

As we do not check our e-mails everyday, please telephone us on 09 629 0338
if the matter is urgent. Thanks.

Visit the Mercedes-Benz Club Auckland website
www.geocities.com/mercauckland/

[Louisa Currie]

I had this problem a little while back. My previous mechanic had fitted the
wrong spark plugs and set the timing too low (I think). I went to John
Andrew Mazda who fitted the correct spark plugs and re-tuned it. No
problems now.

Louisa

From Michael.Hay@nrma.co.nz Fri Apr 27 16:13:48 2007
content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Subject: RE: warm up problems
Date: Mon, 20 May 2002 08:32:47 +1200
Thread-Topic: warm up problems
Thread-Index: AcH++t7YX4XQyoVLSdqnJ7k0KSducAAd0aLw
From: "Michael Hay" <Michael.Hay@nrma.co.nz>
To: "MX5List" <mx5list@mx5club.org.nz>
Content-Transfer-Encoding: 7bit
Precedence: list
Message-ID: <lhnWs.A.2HB.1jXMGB@L733>

I've had the same problem with mine since i purchased it 3 months ago. It had been tuned/serviced etc just before picking it up yet still idled lower than it should, and very occasionally stalled when cold.

Yesterday I unearthed my trusty timing gun, printed of the ignition setting pages from http://www.miata.net/garage/ignition.html#timing and got to work. I adjusted the idle up from around 700 to the recommended 850, and advanced the timing to 14 degrees. Now my baby runs superb. a bit more go, and very smooth idling.

Even if you don't have a timing gun, adjust the idle following the instructions on miata.net. 500-600 rpm sounds a little to low. Am i right or not guys?

[MC]

Also make sure you have TEN & GND connected with a jumper wire/paper clip
in the little black diagnosis connector box when setting the timing and
idle, idle speed should be set at 800/900 rpm
MC