Miata Mailing List: November 1997, Message #52
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From: 	Jeff Anderson <janderso@erols.com>

Subject: Re: Jump-starting a Miata(was RE:'93 batte

Date: 	Sat, 1 Nov 1997 13:38:42 +0000



On Fri, 31 Oct 1997 16:06:43 +0000 "John Freas" <jfreas@gte.net> writes:

>Previously on Jump-starting, Dan Scolnick <dans@interport.net> said...

>> verboten?

>> i've bump started ALL of my manual transmission cars ALL my life when

>> appropriate or applicable. 

>> dead batteries and on hills.

>> why use the starter when you can use gravity?

 

>I couldn't agree more.  Please note that /I/ didn't say it was 

>verboten, I said that IIRC, Mazda and many other manufacturers claim

>it is in their owner's manuals.

>

>	-John

>------------------------------------------------

>John Freas (jfreas@gte.net.nospam)





I agree that a straight stick Miata can often be pushed started quite

easily.  However not always -- it depends on the state of the Miata

battery.  



If the Miata battery is in its state where its voltage is low and high

charging current heats the battery without actually charging it then a

push start will not work.  I've seen Miatas in this battery condition

that would get started with a battery jump and die immediately when the

jumper cables were removed.  As I recall, the first I heard of this was

when MCA wrote about it sometimes happening.



I know that the makers say that the newer cars should not be pushed

started and I often wondered why.  I finally read somewhere an answer

that seems credible.  



It's the possible catalatic converter damage that can result from an

explosion within the catalatic converter when the car is pushed started

rather than under it's own power by the key switch.  When key switched

started the ECU supposedly controls things differently to avoid this

happening.  



I've pushed started newer cars without ever seeing this to be an actual

problem.  I've got a good strong hunch that this could only be a problem

if the starter were cranked and cranked before the push start attempt. 

But what the heck, if it did happen and blew out the cat. then the car

may run better afterwards without the cat's back pressure.    Now I'm

starting to wonder if this method would be a good substitute for the

bypass pipes that can't be sold in the USA. :-)



-- 

Jeff Anderson            @   @     @     @   @@@@@   @      

Arlington, VA           @ @ @ @    @    @ @    @    @ @

91 Silver, 92 Blue     @   @   @   @   @ @ @   @   @ @ @ 

MCA, Capital Chapter  @         @  @  @     @  @  @     @

M Club #97

                  1) I CURE THE MIATA'S BAD HEAD REST SOUND.

                 =========== re mid-96 and older =========== 

 2) Miata special high performance ANTENNA SPLITTER for CB use too. 

    Ends scratching your Miata with magnetically mounted CB antennas.

e-mail for info: janderso@erols.com

  See:  http://www.geocities.com/MotorCity/5361/Jeff.html