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

(continued)

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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Re: K-jetronic FI on QV cars	<– Date –> <– Thread –>
From: Doug and Terri Anderson (dntdock.net)
Date: Fri, 12 Dec 2008 20:40:07 -0800 (PST)