1228746 TBI 305V8 stumble

[Shannen Durphey]

Jay Vessels wrote:

> 
> Problems:  Car idles fine, but off-idle is rough enough to cause a stumble.
>  General lack of power.  If I didn't know better I'd suspect a fuel
> pressure problem.  Could a restriction in the return line cause these
> problems?
Well...  Those are symptoms, not really problems.  Semantics?  No, I'm saying
that without knowing what is really happening it's hard to say what's causing
the problem.  Rich?  Lean?  

> 
> Timing seems to be set right (emmissions label for '85 calls for 0 degrees,
> which seems to make the car start and idle fine, no strain on the starter
> at all).  Set minimum air wihtout problems.
> 
> TPS on this throttle body isn't adjustable, and closed-throttle voltage is
> 0.75V.  Is this right?
Yup.  .75 is high end of limit for some vehicles.  Whatch using for a .bin?

> 
> The '89 used the small-cap HEI which we didn't want to use.  
Perfectly acceptable setup.  Why discard it?

> We re-used the
> (known good) CCC large-cap HEI.  I swapped connectors on the harness so
> that the '89 harness would plug into the '85 distributor.  Timing light
> shows about 12 degrees at idle with the ECM controlling the timing.  Could
> I have a timing-related problem?  

Possibly.

> Surely if I wired it wrong I would have
> thrown a code.
Generally.

> 
> Any help is greatly appreciated,
More details, please.  Lean/rich off idle?  What happens w/ O2 sensor
disconnected?  Warm engine or cold?  Which bcc?  Throttle body match the
engine/calibration?  Injector size correct?  Many car .bins are set for 6 deg.
btdc base, many trucks for zero.  What is the setting in the .bin?  How about
basic spark issues?  TCC problems?  Flat tires? <g>  Faulty wood grain on the
side? <G>  

Hard to diagnose a problem such as "off idle hesitation."  'Specially without
more info.
Shannen


> Jay Vessels
> 1982 Chevrolet S-10 Sport, 2.8V6 TBI
> 1994 Chevrolet Cavalier Z24 Conv., 3.1V6 MPI
> 
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