L-Jet going full Rich on Deceleration Options

[Brian Fuerbach]

1974 1.8 with L- jet. Been playing with a wide band air fuel meter and noticed that when I lift the throttle the AFR goes to max value on the gauge. I thought it was supposed to go lean. I checked the throttle position switch and it checks out fine. Going to check the wiring harness next.

What else should I check? Decel valve?

[wonkipop]

try measuring the Air Fuel Mix at idle too to compare to what you have on throttle lift and coasting.

the decel valve scenario is not unlike the AAV scenario at cold start?
sort of.

the throttle is at closed/idle switch position.
but during that AAV cold start scenario the AAV causes the flapper to open, causes the injector duration to increase and its part of how you get that quicker idle.
its got a scenario to over-write the warm idle scenario that involves more fuel.
there is other stuff going on too, like temp sensors.

at lift off coast its kind of similar but obviously different.
you have the decel valve in combo with the flapper over writing the throttle switch in closed position. its in combo with the fuel pressure drop.
the decel valve is letting the AFM draw air and move the flapper - it follows then it must also be getting a little fuel to burn on its way down to idle?
i mean thats what a decel valve does - at least in L jet?
but if i am correct its got no way of knowing how much fuel its giving other than by spec parameters around what fuel flows through the injector at the lower pressure. if the fuel pressure was higher its going to put more fuel in?
the injector opening is in a routine that conforms to amount of flapper movement, engine revs (from white wire on coil) and closed throttle position. its a timed opening?
so if fuel pressure is off then the timed opening of injectors will deliver too much or too little fuel.

i came across something that said min amount of pressure in system has to be 26 psi to open the injectors. don't know how accurate that is. but it does show that the injectors may have a narrow band of operation below 28 psi and that pressure drop takes them down to something close to the point where they won't open.

its just a thought. there will be L jet experts here that really know.
i am a bit like you. really trying to get my head around my L jet without giving myself too much of a migraine.

@Emerygt350 asked how does it know how fast the engine is spinning.
see here.
i like the way emery is curious about how the L jets are working.
the more stuff i read the more i came across explaining in historical terms just how hell bent bosch was on really simplifying the fuel injection system. anything they could do they did to not have an extra component in it.