Air meter sensor "play"

The 'play' is the free-space between the plunger in the fuel distribution block, and the arm of the sensor plate.

The 'play' is felt as very-easy to move plate, and then there's slightly more resistance as it touches down on the plunger. The plunger resistance is very minimal as felt at the sensor plate.

How do you know the left bank (7-12, I'm assuming) is rich?

If you have zero play on the 7-12 bank, it could be a few things:
The adjustment screw is very tight and has taken out all the play.
The plunger is stuck full-open in the fuel distributor and so contact is never felt, basically 'infinite play'.

Which family engine do you have? Euro spec? Do you have oxygen sensors?

There is no factory setting for the amount of 'play'. The WSM on D33 describes setting the 'base' mix adjustment of the fuel distributor (aligning). The process in a nutshell is to back off the mixture screw and then disconnect a fuel injector line at the fuel distributor, and jumper the fuel pump to run. No fuel should flow. If it does, continue to loosen the screw until no fuel flows (this is best done with two people and only running the fuel pump a few seconds at a time). Once no fuel flows, tighten the mixture screw until fuel just begins to flow, then back off the screw again by a half-turn. Follow the mixture adjustment procedures from there, which varies between cars with and without O2 sensors.

 

"Play" only applies to (and should be present on) the KE-Jet TR (not the K-Jet TR). If there is no "play", the plunger is (already wrongly) deflected upward -- so the slits could (wrongly) be open when no air is entering the engine.

CIS Flow Tech recommends 1 to 3mm play (measured in airflow plate deflection from its rest position) being present as the sanity check IIRC.

 

Also, with the setup used on the 3x8s --- not sure if the same set up is used on the injected Boxers or the TRs ? --- the air flow sensor is inverted (upside down) as compared to all (that I am aware of at least) other CIS applications. And, in that case (Ferrari) the plate should not have any free play at all.

 

The plate has free play in the 308 as well. 3-4mm is normal, if not ideal.

 

I am afraid that is simply not correct.

The sensor plate on the injected 3x8s / Mondials does not have any free play --- therefore there is no free play adjustment or specification.

There is a "rest / stop" height adjustment and specification, however.

Again, I am not sure whether the injected BB / TR uses a similar air flow meter, or if they use the more conventional setup (like most German cars running CIS) where the plate moves up (instead of down), and there is free play between initial sensor movement and when it first contacts the tip of the control plunger.

 

All of the injected 308, 328, and brother Mondials are K-Jet = no free play when the fuel pump is running with engine not running (because there is no physical stop for the plunger except for the airflow plate mechanism contacting the rest pin) -- whether or not the airflow metering device is the downdraft or updraft style doesn't make any difference for this. KE-Jet does have free play when the fuel pump is running with engine not running because there is a separate physical stop for the plunger itself (again, regardless of whether the airflow metering device is the downdraft or updraft style).

 

Does someone have a diagram to show these parts and exactly what dimensions are being adjusted and how?

Thanks

Phil

 

TR WSMPage D35
Cat Supplement Page D71 -

Lots more info in the WSM...

Rgds,
Vincenzo
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Try putting a few miles on it before you send off fuel diffs. There is much truth to the old adage 'Italian tune up'. You might be surprised how some of the little fuel gremlins go away after some spirited driving.