[urq] hesitation, bucking on takeoff - not resolved yet!

[Buchholz, Steven]

... I never remember which situations I've added a tuppence to ...
thought I had offered up the question on the OXS Freq Valve before ...
don't remember that being addressed ... 

I see that you've swapped F/TCU, so that does reduce the likelihood
somewhat ... but ... 

Have you listened for the buzzing of the freq valve when the car is
exhibiting the symptom?  

Do you know for a fact that the fuel pump is staying on during these
episodes?

I think I saw others post about what you see on the tach ... one thing
that is very common on V8s is that the flywheel sensors fail ... usually
with heat related symptoms ... one of these days I want to see what
changes on a bad as compared to a good sensor ... but in any case, if
you lose either the reference or the speed sensor on an I-5 the F/TCU is
not going to have the info it needs to determine when to fire the spark.
I suppose another component which may have thermal issues is the Hall
Sender in the dizzy ... here again, if the signal from the Hall Sender
gets screwed up the F/TCU will not be able to determine when to fire the
coil.  Typical troubleshooting technique for the flywheel/dizzy sensors
is to cool them off ... 

Steve B
San Jose, CA (USA)
> 
> Following through with others advice:
> 
> Swapped ignition module - located above glovebox.
> 
> Checked distributor wiring - no problem there and it has the connector
and
> locking clip still in good condition.
> 
> Checked idle switch - good continuity and about .003ohm resistance.
> Disconnected switch to run closed loop.  I re-adjusted so duty cycle
is 50%
> +/- 1% at idle with no switch.  Problem still happens with switch
> disconnected, but may have run slightly better - hard to tell.  I
reconnected
> the idle switch and duty stayed as set.
> 
> The car accelerates great between bucks - spins wheels then cuts,
spins then
> cuts while trying to get up my steep driveway.
> 
> I am wondering if it is not getting power on one or more cyl. either
due to
> spark or compression.
> 
> I really have gone over this car and ignition was all new, and now the
fuel
> injection is sorted too - everything cleaned up.
> 
> I can feel that with the positive changes I've made, once I repair
this
> annoying problem, this car is going to run fantastic.  If I could just
figure
> out what is not working right - as it is the car is not driveable.