Re: Timing Jump on 165/TPI System

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

| 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
| -----Original Message-----
| From: John T. Martin <gmman@eskimo.com>
| To: gmecm@efi332.eng.ohio-state.edu <gmecm@efi332.eng.ohio-state.edu>
| Date: Sunday, January 09, 2000 10:33 AM
| 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.
| >-----Original Message-----
| >From: Craig Moates <craig.moates@home.com>
| >To: gmecm@efi332.eng.ohio-state.edu <gmecm@efi332.eng.ohio-state.edu>
| >Date: Saturday, January 08, 2000 9:08 PM
| >Subject: Timing Jump on 165/TPI System
| >
| >
| >Folks,
| >
| >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
| >
| >
| >
|