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]

chookyard = chickenyard.

think the limeys call them chooks too.
a ye olde english thing more so than original aus slang.

limeys = usa slang. = poms in aus. translates as prisoners of his/her majesty i believe.
ie prisoners trapped in the motherland. ignoring as australians do that they were the original prisoners of another prison island. aus slang is endless circles of b s.

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getting back to topic.
does this sound like your afr readings brian.

[Van B]

chookyard = chickenyard.

think the limeys call them chooks too.
a ye olde english thing more so than original aus slang.

limeys = usa slang. = poms in aus. translates as prisoners of his/her majesty i believe.
ie prisoners trapped in the motherland. ignoring as australians do that they were the original prisoners of another prison island. aus slang is endless circles of b s.

------

getting back to topic.
does this sound like your afr readings brian.

That’s opposite. That example is going super lean.

[wonkipop]

chookyard = chickenyard.

think the limeys call them chooks too.
a ye olde english thing more so than original aus slang.

limeys = usa slang. = poms in aus. translates as prisoners of his/her majesty i believe.
ie prisoners trapped in the motherland. ignoring as australians do that they were the original prisoners of another prison island. aus slang is endless circles of b s.

------

getting back to topic.
does this sound like your afr readings brian.

That’s opposite. That example is going super lean.

thats good,
its interesting for me then.
it seems to say with those 911s its not shutting off fuel, but the fuel is going to a lower level not influenced by air mass sensor (or equiv to afm, not sure what they have).
and since its not getting air its a pretty small amount of fuel?

must be what mine does when i back off gas without decel. just goes down to idle metering of fuel. i sure don't get what that pelican poster called popping. i might get some what i would call burble. so i doubt i get the rich thing fuel dump. probably get the opposite. not enough for anything much to happen except engine braking and a bit of fuel being expelled into exhaust and doing a little snap and crackle without the pop.
but there is no real combustion going on. its just spitting out a bit of fuel that is coming in. which is detonating in the exhaust. but its not a "real" rich condition thats occuring under true power combustion.

brian's thing is interesting.

is it possible that the oil filler cap might be coming into play.
given we discovered the horror of it being a pcv valve.

the mechanism seems to want to close off the crankcase if exposed to engine vacuum.

it can't get exposed to that when the throttle is closed. not via the throttle plate - crankcase vent port is above the throttle plate.
but could it be drawing as a result of the decel valve wanting to draw air in during decel. be exposed to fairly high manifold vacuum (draw) that way during over-run. is the pcv valve then meant to close in those instances. could it be drawing in excess of crankcase vapors, blow by fumes, oil mist etc.
could that increase the afr reading? "fowl plugs" as emery would say. you guys would know more than me about what can send one of those probes down the scale to say there was more "fuel" in it - besides perhaps real fuel so to speak.