Re: Timing Jump on 165/TPI System

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

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@bright.net>
| To: gmecm@efi332.eng.ohio-state.edu <gmecm@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@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
| >
| >
|