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

[Pasqualoni, James E]

On Thursday, October 20, 2005 10:12 AM, Dave Lawson referenced:

>Do these even come into play once the engine is started?  I thought 
>once the engine "synced up" Hall,TDC and Ref sensors, that the only one

>that is really used from that point on is the Hall sensor.

Once the engine is started, the hall sensor may be disconnected. But the ECU
needs the ref mark sensor and the timing(speed) sensor in order to determine
engine position. It reads the ref mark sensor (60 deg BTDC) and then counts
flywheel teeth to determine engine position for timing. I would perform the
checks on pages 32-34 of the IST manual and verify functionality of the
speed and ref sensors.
-
Dave
-------------------------

I had similar symptoms with my 5ktq.  The bushings in the starter had let
go, causing the starter gear to crack a few teeth on the worm gear of the
flywheel.  Consequently, the ref sensor was not sending a spark signal to
the distributor for the #1 cylinder.  I would experience significant bucking
of the car at high loads and low rpm.  Once the revs were up, there seemed
to be enough residual spark in the distributor to get some ignition to the
cylinder, and it ran much better.  Could be the wiring for the ref sensor
that is causing your issues?

HTH,
Jim