Re: Timing Jump on 165/TPI System

["Bruce Plecan" <nacelp@bright.net>]

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@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@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