stumbling 4kcsq

[rob hod]

    Hi Jim

    I had a similar problem. A new set of plugs made a big improvement but
it was properly cured by a new set of injectors. The injectors were a bit
leaky, had varying spray patterns and were quite corroded along their length
which was  preventing the flow of air from the shrouding area through the
tips. Its my guess that this flow of air is very important for efficient
atomisation at low flow rates. Bad injector seals may also be causing a
vacuum leak (as suggested by others).

    Probably worth doing the vacuum leak test(s) and then pulling your
injectors to see what condition they are in. Best not to pull the injectors
unless you have some new seals (the big o-rings) as if the old ones are very
old they may disintegrate when you try to get the injectors out. Then again
if you don't know the history of the car it may be worth just shopping
around for a good price on a new set of injectors which should include the
seals, and be done with the job.

    BTW there is no idle mixture adjustment as such, just an overall mixture
adjustment.

    HTH


rob
----- Original Message ----- > Message: 14
> Date: Mon, 4 Mar 2002 11:29:33 -0800 (PST)
> From: "James D. Hanson" <jhanson at westmont.edu>
> To: <quattro at audifans.com>
> Subject: Re: >
> Oh, it just occurred to me that this may be related.. (duh)
> it failed emissions at idle, with high CO levels.
> Running too rich?
>
> Thanks,
> Jim
>
> On Mon, 4 Mar 2002, Brady Moffatt wrote:
>
> > Jim,
> >
> > Mine did the same thing, and what "cured" it was richening up the idle
> > mixture a bit. What  _caused_ the problem, though, was some vacuum leaks
> > (manifold gaskets, injector seals). Once those were fixed, the mixture
had
> > to be leaned back out a bit. HTH.
> >
> > Cheers,
> > Brady Moffatt
> > Montreal, Quebec, Canada
> > 86 4ksq, 282,000km
> > 72 Datsun 240Z, 180,000 miles
> >
> > ----- Original Message -----
> > From: "James D. Hanson" <jhanson at westmont.edu>
> >
> >
> > > My 87 4kcsq seems to have a problem... when accelerating away from a
stop,
> > > the engine stumbles between about 1000 and 2000 rpm.  Accelerator
position
> > > seems to have no effect.  If I rev the engine first a few times, then
> > > accelerate, there's no problem.  Similarly, if I don't give it a
chance to
> > > settle into idle, its fine.  This happens warm and cold, though its
most
> > > noticeable when the engine is warm.
> > > Any ideas what is causing this?
> > >
> > > Thanks,
> > > Jim
> > >
> >
>
>
>