Ferrari Mailing List: Re: K-jetronic FI on QV cars

[Rick Lindsay (rolindsay]

My car is a Euro QV running K-Jetronic w/o lambda.  It has no cats.  When the 
car was 'federalized' a begillion years ago, they added an aftermarket lambda 
sensor, a cheesy little control module in a plastic box and a valve inserted in 
the control pressue line to modulate the control pressure and therefore, the 
fuel:air ratio.  All of that add-on crap failed and is now gone.

The whole purpose of this thread, as it began, was to understand how this car 
should work in its native state.  Some of the parts that modulate the basic 
fuel and air metering are not working correctly.  Repairing those woes is my 
goal.

rick
'83 Mondial QV
'79 308GTB


--- On Fri, 12/12/08, Doug and Terri Anderson <dnt [at] dock.net> wrote:

> From: Doug and Terri Anderson <dnt [at] dock.net>
> Subject: Re: [Ferrari] K-jetronic FI on QV cars
> To: "rolindsay" <rolindsay [at] yahoo.com>
> Cc: ferrari [at] ferrarilist.com
> Date: Friday, December 12, 2008, 10:40 PM
> Fuel pressures and CO setting is what makes the system tick.
>  The O2 sensor 
> is there ONLY for dithering the fuel (rather oxygen) more /
> less to make the 
> three way cat work.  Much later, the O2 or Lambda sensor,
> multiple sensors 
> play a major major role in controlling emissions and fuel
> trim.  Word of 
> caution - NEVER use red RTV unless branded O2 safe.  NEVER
> use any silicone 
> cleaners around the intakes.   Just ta thought - I could be
> wrong/
> DOUG
> 
> ----- Original Message ----- 
> From: "E M" <pokiebaron [at] gmail.com>
> To: "DOUG" <dnt [at] dock.net>
> Cc: <ferrari [at] ferrarilist.com>
> Sent: Thursday, December 11, 2008 4:27 PM
> Subject: Re: [Ferrari] K-jetronic FI on QV cars
> 
> 
> > Oh yeah, and for those how haven't tinkered with a
> CIS system before,
> > remember, the system is under a LOT of pressure!  Use
> caution!
> >
> > Ed
> > 911SC
> >
> > 2008/12/11 Jeff Greenfield <coyote [at] acme-ltd.com>
> >
> >>
> >>   Rick -
> >>
> >>
> >>
> >>   You wrote: "Cold start enrichment is
> handled by the cold start
> >>    injector. Warm-up idle speed is controlled by
> the Aux Air Valve"
> >>
> >>
> >>
> >>    This is not entirely  correct. Cold start
> enrichment is helped by the
> >>   cold start injector by way of the Thermo Time
> Switch (TTS), however
> >>   the cold start injector ONLY fires during
> cranking.
> >>
> >>
> >>
> >>   The warm up regulator does more to control the
> fuel mixture during
> >>   warm up. CIS is dependant on fuel pressure (and
> the pressure
> >>   differential in the fuel distributor) to control
> mixture, so the WUR
> >>   varies the fuel pressure depending on engine
> temperature. If the fuel
> >>   pressure in a CIS system is off just a little
> bit it will cause all
> >>   kinds of wonky behavior.
> >>
> >>
> >>
> >>   If there is any doubt that there are mixture
> issues, then the fuel
> >>   pressure needs to be checked. This requires a
> fuel gauge with a 'T'
> >>   and a switching valve so you can isolate the
> system, primary and rest
> >>   pressures. This a little more involved than just
> plumbing a gauge into
> >>   the circuit, firing up the fuel pump, and
> reading the pressure.
> >>
> >>
> >>
> >>   20 or so some years ago, CIS was very common on
> VW's, Audi's, BMW's,
> >>   Volvos, and a bunch of others. I've worked
> on most at one time or
> >>   another, and am very glad that there are not
> many cars with CIS left
> >>   in this world. I swore I would never own a car
> with CIS, then I had to
> >>   go and buy a 308 QV :-)
> >>
> >>
> >>
> >>   Jeff - who after all these years still does not
> fully understand CIS,
> >>   but I seem to understand it well enough to
> diagnose and repair them.
> >>
> >>
> >>
> >>   -------- Original Message --------
> >>   Subject: Re: [Ferrari] K-jetronic FI on QV cars
> >>    From: rolindsay [at] yahoo.com
> >>   Date: Thu, December 11, 2008 6:49 pm
> >>   To: Jeff Greenfield <COYOTE [at] acme-ltd.com>
> >>   Cc: ferrari [at] ferrarilist.com
> >>   The story I'm told is that the US spec cars
> have a higher initial idle
> >>   to heat the cat (for emissions control). Since
> the Euro cars of the
> >>   same vintage don't have cats they need only
> idle a little faster to
> >>   aid warmup and to idle stable when cold.
> >>   Cold start enrichment is handled by the cold
> start injector. Warm-up
> >>   idle speed is controlled by the Aux Air Valve.
> Yea, it works like a
> >>   vacuum leak. ;-P
> >>   Rick
> >>   Sent via BlackBerry by AT&T
> >>   -----Original Message-----
> >>   From: JAshburne [at] aol.com
> >>   Date: Thu, 11 Dec 2008 18:10:56
> >>   To: rolindsay<rolindsay [at] yahoo.com>
> >>   Cc: <ferrari [at] ferrarilist.com>
> >>   Subject: Re: [Ferrari] K-jetronic FI on QV cars
> >>   Rick
> >>   FWIW, my 400i has two of the K-Jetronic FI
> systems and it typically
> >>   idles
> >>   around 1,300-1,400 after startup but fairly
> quickly (< 5 minutes)
> >>   settles down
> >>   to 1,000 rpm idle. 2,000 rpm sounds a bit high
> for an idle speed even
> >>   if
> >>   right from a cold start.
> >>   John
> >>   In a message dated 12/11/2008 6:02:02 P.M.
> Eastern Standard Time,
> >>   coyote [at] acme-ltd.com writes:
> >>   Rick -
> >>   Yes and no.
> >>   The US cars are more complex than those sold in
> the rest of the world,
> >>   and they have more stuff that affects this. I
> also believe (but could
> >>   be wrong) that the euro cars don't idle as
> high on a cold start.
> >>   It also depends a lot on ambient temperature. If
> the car has been left
> >>   out overnight in 20 degree weather, the idle
> won't be as high since
> >>   the transmission oil and other fluids being
> thicker will cause
> >>   significant drop.
> >>   When it is about 50 - 60 degrees, yes the idle
> will be somehere around
> >>   1500 - 2000 for a few minutes.
> >>   But, if the car starts ok when cold, and drives
> ok immediatley on a
> >>   cold start, then everything is alright.
> >>   If there were a problem with the AAV, it most
> likely would not idle
> >>   well when cold. You could try cleaning the AAV,
> sometimes they get
> >>   gummed up.
> >>   A problem with the cold start injector, or TTS
> would cause an extended
> >>   crank when cold, but once started should not
> have any effect.
> >>   A problem with WUR, would cause a bunch of
> varying idle and
> >>   driveability problems.
> >>   I had a 3.2 Mondial in the shop this past summer
> that had come to MA
> >>   from AZ. The AAV had been disconnected. The car
> wouldn't idle
> >>   initially on a cold start. We're talking
> ambient temps of 60ish
> >>   degrees in this case.
> >>   Reconnected it and all was well.
> >>   YMMV,
> >>   Jeff
> >>   Sent from my iPhone
> >>   On Dec 11, 2008, at 4:21 PM, Rick Lindsay
> <rolindsay [at] yahoo.com> wrote:
> >>   > Hey Gang,
> >>   >
> >>   > On your QV 3x8s and Mondials, does the idle
> speed run high at start-
> >>   > up? I have heard stories of the US cars
> idling really high
> >>   > (>2000rpm) when first started cold.
> Every book I have read on K-
> >>   > Jetronic discussed the cold start injector
> and the additional air
> >>   > valve to raise cold idle speed. My Euro. QV
> has none of that
> >>   > behavior. First start-up or after a long
> run, engine cold, hot or
> >>   > in between, it idles at 1000rpm. Should it
> have a higher idle speed
> >>   > when cold?
> >>   >
> >>   > What I'm asking is whether the cold
> start circuit in my car is
> >>   > working properly. It starts flawlessly but
> has no increase in idle
> >>   > speed at all.
> >>   >
> >>   > Thoughts?
> >>   >
> >>   > rick
> >>   >
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