No subject

Thu Nov 20 15:09:11 EST 2003

distributor pulse is coincident with a crank pulse, and the ECU will
consider this unique occurence to be #1 cyl.Comp TDC, inasmuch as it knows
nothing of the relative physical placement of parts.  Thus, the ECU will
control and fire the engine on either crank TDC, always the one to which the
distributor is timed.  Therefore I believe, and Dan has so proved that
engine can function properly with the distributor located 180d form its
normal oriention!

Smile Scott, you can have the last word.


> From: QSHIPQ at
> Date: Sun, 23 Jun 2002 15:37:41 EDT
> To: 200q20v at
> Cc: dans at, b.m.benz at, urq at
> Subject: RE:  Boost and TDC and distributors
> Gentlemen:
> If you ONLY removed the distributor and left the cam and crank TDC's intact
> (as described), you CANNOT put the distributor in 180 off, or it won't run.
> You can physically put the distributor in any way that fits, you just need to
> rotate the body until you have rotor pointing at number 1 (window plate hash
> mark and nick in dist aligned).
> If you are 180 out you will have the distributor 180 degrees from the nick on
> the outer lip when the crank shows TDC -0-.  When this happens, you can't
> start the motor, because the timing reference pin and the dist window need
> this condition for Motronic to fire the car.  AFTER the car is started, the
> dist window is ignored, so you can rotate the distributor and the car will
> continue to run, but should toss a code.
> Ned and I had several discussions on TDC windows over the years, mostly on
> the MC and early urqs.  At one of the Grattan track events in the early 90's
> there was an urq that wouldn't start when warm.  What happens in the urq's
> (and could happen in any car that is teetering on the edge of the dist
> window) is that the head warps slightly causing the distributor to misalign.
> Car still runs, but at hot shut down and restart the window was out of whack.
> Car cold, no problems.  Did this on my '84 when I first got it too.
> WRT 20vt stuff Dan, you could have too much slop in the gears (metal or
> plastic), or you were just on the edge of the window.  That said, when you
> install the distributor, many times you will find that the TDC reference hash
> are off a bit sometimes causing a "perfect" tdc reference to be not so.  Your
> procedure of moving the distributor CW and CCW is what most of us end up
> doing with the same problem.
> I'm not at all with the thinking that you were 180off in timing Dan, but -0-
> on the distributor is +/- 2 degrees if service tech manual recall serves.
> That's a 1% rotational error.
> Scott Justusson

More information about the 200q20v mailing list