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

[E M (pokiebaron]

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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