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]

i am doing some more reading on just how the L jets handled backing off on decel.

i feel pretty sure that mine, without its decel valve connected would also be appearing to go very rich when i come off gas. doing a fuel dump more or less. probably like yours.
but maybe for slightly different reason. ie no decel valve.

there is no fuel cut off in these early L jets.

making sure the fuel pressure regulator is being operated by the vacuum line at both idle and coming off the gas is part of confirming the system.

but that i think is the way they are.

the distributor is definitely doing something to help clean up the hydrocarbons.
so it may well be that there is nothing here of concern if your afr etc are fine everywhere else.

by looking for info on your afr condition i now understand something about mine when its cold and i give it a rev and it almost dies and comes back to life. i'll post that up when i can summarise it simply and clearly. but its down to what the distributor is doing in that instance on my car.

[Brian Fuerbach]

by looking for info on your afr condition i now understand something about mine when its cold and i give it a rev and it almost dies and comes back to life. i'll post that up when i can summarise it simply and clearly. but its down to what the distributor is doing in that instance on my car.

While adjusting my decel valve I was able to simulate the same die and comeback to life situation as you. I think without the valve you will always have this issue.