From:	Dave Darling [darling@simlab.arc.nasa.gov]
Sent:	Monday, May 24, 1999 10:27 AM
To:	wayne@pelicanparts.com
Subject:	Re: [914] Backfiring 914

>Date: Mon, 24 May 1999 09:49:04 -0700
>To: Alex O'Connor <AlexO35@aol.com>
>From: Dave Darling <darling@simlab.arc.nasa.gov>
>Subject: Re: [914] Backfiring 914
>Cc: "914" <914@rennlist.org>
>Bcc:
>X-Attachments:
>
>At 8:06 AM -0700 5/22/99, AlexO35@aol.com wrote:
>>     I got my new engine installed and running this week.  The only problem
>>is an annoying backfire.  What causes an engine to do this?  I haven't set
>>the timing yet because of this problem.  Any thoughts?
>
>	Improper timing can cause backfiring.  Having plug wires swapped
>around can cause very hard starts, and TRULY impressive backfires.  (My
>friend who was helping me out jumped about a foot, and it took a minute
>for our ears to stop ringing!)
>	Backfires are actually caused by a wide variety of things.  I have
>had problems with the timing (pop the distributor back in and guess is NOT
>a very good way to set it!), the swapped plug wires, the ignition cut-off
>rev limiter, a valve seat falling out of the head and popping back in again,
>and VERY rich fuel mixtures.  So far.  I am told that lean mixtures can also
>cause backfires--don't know the mechanism, though.
>
>	I'd suggest adjusting the valves, doing a compression check, and
>setting the timing.  See if that helps at all.  Then start the FI (or carb)
>diagnostic procedures.
>
>--DD
>

Dave Darling                                  74 914 2.0 (decapitated)
                      darling@simlab.arc.nasa.gov
                        "OFF WITH ITS HEADS!"


<img border="0" src="http://www2.pelicanparts.com/track.cgi" width="3" height="3">