[Diy_efi] 4.3L TBI Timing Issues.

[David Allen]

  It sounds like the ignition moule is running in timing bypass mode.  This
should flag a code and turn on the check engine light but there are
instances where it might not.
  I would verify the check engine light is really working and there are no
codes. After that make sure the 4 wires between the ECM and ignition module
are good, and the "Set Timing" connector is not unplugged.
  Maye someone else will think of something else to try too!
David


----- Original Message ----- 
From: "David Daniel" <ss396 at pinn.net>
To: <diy_efi at diy-efi.org>
Sent: Friday, December 09, 2005 6:57 PM
Subject: [Diy_efi] 4.3L TBI Timing Issues.


> I recently transplanted a TBI 4.3 out of a '85 Monte Carlo into my '81
> Malibu. I've been trying to diagnose a slight stutter under light
> throttle conditions. Tonight I hooked the timing light up to check the
> spray pattern on my TBI injectors. They looked fine, so I took a look
> at the timing. I could increase the throttle slowly, holding steady at
> several points, and the timing was not advancing at all. Then, once I
> get to a certain point, I see the timing advance all at once. I know
> it shouldn't jump like that, but what could be causing this to happen?
> I can feel it when I drive, too. It kinda stutters as I roll on the
> throttle, then it smooths out and takes off once the RPM's come up a
> bit. I don't have a tach yet, so I'm not sure what RPM range this is
> happening, and the CEL is not lit. Any ideas?
>
> Dave D.
> '81 Malibu Wagon <-4.3 TBI, the st-st-stutterer
>
>
>
>
>
> -- 
> No virus found in this outgoing message.
> Checked by AVG Anti-Virus.
> Version: 7.0.323 / Virus Database: 267.13.12/193 - Release Date: 12/6/2005
>
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/diy_efi
>