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]

here is another note on that decel thing.

the idea that the L jets can do a lean condition on deacceleration may not be entirely attributed to its primitive lunar module brain and pre program routines.
it might also be a kind of frankenstein sledgehammer/cuckoo clock attached to the side of it all with vac hoses.

ie it just burns the excess hydrocarbons on back off with a good old vac retard trick.

reason i say this is @Van B brought up the different decel valve on the 75 1.8s on another thread.
and it is different. its a big monster flat can thing. which i know little about.

but i do know that the exhaust manifold stubs on the 75 1.8s were different as well.
they were thicker and held more heat in them. vw and porsche referred to these thicker stubs with real fancy words. "thermal reactors". not the thermal reactors we later came to know and love.

i'm putting 2 and 2 together here and coming up with 15 i know.

but a bigger decel can (more O2?), get those exhaust stubs nice and hot, change the distributor slightly (think its a different distributor too) and........do you burn even more hydrocarbons coming off the gas pedal and pass the emission test without an air pump.
and all the time you think the dumbo brain controlling it all is doing something smart with the air/fuel mix.

i dunno.

in 76 the 912E had to get an air pump. i don't know when and how the air pump kicks in. don't have a 912E. never seen one. none here. but they had L jet and had to get that air pump to pass the ever increasing emission test. 914 1.8s didn't need the air pump. so is the whole lean off thing about these gadgets and requirements of emissions.

i would have thought a temporary spike in richness on back off is not a terrible thing.
but if is persistent then that is something different i'm guessing.