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

[Thatcher Hubbard]

I think the ICU stayed in the same place for the life of the WX/WR/MB cars.
Ben, it's easy to miss because it seems way too small for something that's
electronic (about 2" square), especially if you've seen the F/TCU in the
passenger footwell. It will have a thick black connector going into it and
usually has a big felt pad on the underside. You can see it pretty easily if
you drop the glove box out of the car. I know that there are a few ICUs that
fellow listers have been able to loan out for troubleshooting purposes. I do
not need mine anymore, I'm going EFI, but I suspect the ICU may have been
the cause of my bucking problem and it may not help you with your problem at
all. If you would like I'd be more than willing to drop it into the mail to
you at some point though.

It's important to see what your tach does when the car is bucking. Mine
would drop to 0 and then bounce up towards redline, I could tell by sound
that the engine was still turning, and so conclude tha the tach signal was
wrong. Since the tach signal comes off of the coil, it indicated to me that
a) the coil was shot, b) the coil was not getting a signal to fire or c) the
12v supply to the coil was cutting out under certian conditions so it was
unable to fire when it was told to. If your tach doesn't behave oddly (i.e.
it seems to consistently indicate what the engine is actually doing) you may
have to look elsewhere, but it's good indicator to start with.

On 10/19/05, Ed Kellock <ekellock at gmail.com> wrote:
>
> The ignition module is up under the dash over on the passenger side. You
> have to remove the glove box to get to it.
> Mine is an '85 just in case the earlier cars had it in a different spot.
> Ed
>
> On 10/19/05, Ben Swann <benswann at comcast.net> wrote:
> >
> > Where is the ignition module on this car? It is seeming to be more of an
> > ignition problem.
> >
> > Whatever it is it is definately due to getting warm/hot - probably not
> > helping my trouble-shooting..
> >
> > Ben
> >
> > [Date: Wed, 19 Oct 2005 14:07:55 -0600
> > From: Thatcher Hubbard <thatcher.hubbard at gmail.com>
> > Subject: Re: [urq] hesitation, bucking on takeoff - not resolved yet!
> > To: Urq List <urq at audifans.com>
> > Message-ID:
> > <7cd43ae20510191307m3c1a7c51ma28973cb1a7579a6 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > I would suggest that since all of the work you've done to your fuel
> system
> > seems to have made little difference that you should check the ignition.
> > You
> > mentioned that you replaced your coil, have you checked the ignition
> > control
> > unit?]
> >
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