Hi Guys.
I have rebuilt a 800cfm +1975 carb with the APT valve.
To dial it in properly i have been using a wideband sensor in the x pipe of my dual exhaust.
My problem is that when i decelerate or start braking, the engine leans out drastically.
I have tried 3 different float levels to be sure that was not the problem.
With the float level 10mm the car would cruise too lean, while with the float at 6mm i could not adjust the idle screws properly(turning them all the way in resulted in AFR 14:1, while anything but fully in would create a rich idle of 13 - 13.5:1.
At 8mm float level the car is cruising a bit too lean still.
I have dialed the timing in perfectly, making sure TDC was actually TDC by uaing a piston stop turning engine both ways and marking up during the procedure.
The timing is at 15 in idle, 34 at 3000rpm with 10 from the manifold vacuum advance. New hei dizzy, plugs and wires. Timing is dead on in my opinion!
Can anyone help me out as to what i should try to not have the car die on me during braking?
Make sure the fuel pressure is not too high/low?
Suggestions?
The engine is a rebuilt stock bottom end 1975 L48 corvette engine sporting a mild cam pulling 19hg vacuum, Edelbrock 65cc perf.rpm heads, performer intake, Long tube headers, dual 2.5 exhaust with an X pipe and free flow mufflers.
Car is an 87 el camino with a th350 trans abd stock non posi 2.41rear end!
Thanks in advance
