Timing Jump on 165/TPI System

[Mark Romans]

I've got a MSD6AL, with Accell coil in cap. MSD box is hidden under the
battery box.
It stalled on me 3x today.  All at idle or on deceleration.  Restarts fine.
Mark
-----Original Message-----
From: Bruce Plecan <nacelp at bright.net>
To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
Date: Monday, January 10, 2000 9:36 PM
Subject: Re: Timing Jump on 165/TPI System


>Ahh, get a MSD low resistance center bushing, and a good aftermarket coil.
>MSD makes a kit for using a remote coil.
>  Better yet get a late model small cap distributor, and use a good coil
>with that.
>Then might even use a good spark box.
>  I know not oem looking then, but worth it, IMHO.
>Using a remote coil late dissy, I have 230K miles on the original
>module........
>Grmpy
>
>
>
>| Sorry Bruce:  Forgot to answer, large cap dizzy!
>| Mark
>| -----Original Message-----
>| From: Bruce Plecan <nacelp at bright.net>
>| To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
>| Date: Sunday, January 09, 2000 6:51 PM
>| Subject: Re: Timing Jump on 165/TPI System
>|
>|
>| >
>| >It usually makes the engine surge wildly, when it applies, on modified
>| >engines, even mild surge on stockers.
>| >  The mechanics are opening IAC, and adding fuel.  If bad enough I think
>it
>| >might move the timing.
>| >Grumpy
>| >  You might just for grins try uping the BL to a higher number for the
>idle
>| >stall thing.
>| >
>| >
>| >| I just rechecked and 700 rpm's for both GDF files, stall1 and stall2.
>I
>| >| wonder if that has something to do with stall saver rpm's?
>| >| Next question, what specifically does stall saver do?
>| >| Mark
>| >
>| >| From: Bruce Plecan <nacelp at bright.net>
>| >| Subject: Re: Timing Jump on 165/TPI System
>| >| >| Hey Bruce: If I disconnect my est connector, should I see the
>advance
>| >at
>| >| >| 2500 rpm?
>| >| >Yes
>| >| >| I am wondering if this is why I have the idle problem.  Remember
how
>| >the
>| >| >| signal goes to zero advance?
>| >| >As I recall it did that during the stall and it was right at 400 rpm,
>| >which
>| >| >is when the ecm drops out of bypass, and it would read 0 as I
>understand
>| >| >things.
>| >| >The only failure I've personnally had or diagnosed with a gm module
is
>| >hot
>| >| >stalling, and progressing to where the engine needs to cool before it
>| >would
>| >| >restart.
>| >| >BTW, is yours a large or small cap Dissy
>| >| >Bruce
>| >| >| Mark
>| >| >| From: John T. Martin <gmman at eskimo.com>
>| >| >| Subject: Re: Timing Jump on 165/TPI System
>| >| >| >My  $.02
>| >| >| >That is a normal condition, also a test for P/U coil signal
>strength.
>| >| The
>| >| >| >advance is triggered by the P/U coil signal amplitude, not RPM. It
>is
>| >a
>| >| >| back
>| >| >| >up as I understand it, but a good test if you suspect a weak
magnet
>| in
>| >| >the
>| >| >| >dist. We had a run of K engines with shaft problems a while back
>and
>| >in
>| >| >| >bypass (est disconnected), 2500 rpm the advance was not triggered.
>| >Also
>| >| >the
>| >| >| >weak pick-up signal affects idle quality.
>| >| >| >Subject: Timing Jump on 165/TPI System
>| >| >| >A question:
>| >| >| >With timing control connector disconnected (ie. setting timing on
a
>| >| >| >165-based TPI motor), timing should sit still, which it does for
me
>| at
>| >| >low
>| >| >| >RPM. However, when I idle it on up to say 2000 or 2500, it seems
to
>| >| >advance
>| >| >| >like 12 degrees or so, instantaneously, and hold up there until I
>| idle
>| >| it
>| >| >| >back down. Then it jump-returns to the previous value. This is all
>| >| >| >timing-light based. Any thoughts on what is being seen? There's
>about
>| >a
>| >| >1-3
>| >| >| >degree drift on idle-up, probably from timing chain stretch, but
>| >that's
>| >| >not
>| >| >| >huge.
>| >| >| >Anyways, fishing for thoughts. It's not problematic, just would
>like
>| >to
>| >| >| >understand what's happening and why.
>| >| >| >Sincerely,
>| >| >| >Craig
>| >
>| >
>|
>