Technical Help with vacuum line.

[SHERMAN41]

I just droped a new tuned Webber 32/36DVA I’ve been working on the ‘78 124 for a month on and off, I hoped to get a bit more hp out of the old girl. I removed the smog/air pump units, and all it’s equipment, gotta be 40lbs +. Any way fired her up, sounds bad, back firming on start-up at carb.just running lvery poorly. Has electronic ign (fireball 3000), basicly theres no vac landing points.
there’s one port on carb I plugged,and caped off hole in airleaner plate.
What am I doing wrong…?…..Please help, I want to drive the car soooo badly.

 

[bugsymike]

I just droped a new tuned Webber 32/36DVA I’ve been working on the ‘78 124 for a month on and off, I hoped to get a bit more hp out of the old girl. I removed the smog/air pump units, and all it’s equipment, gotta be 40lbs +. Any way fired her up, sounds bad, back firming on start-up at carb.just running lvery poorly. Has electronic ign (fireball 3000), basicly theres no vac landing points.
there’s one port on carb I plugged,and caped off hole in airleaner plate.
What am I doing wrong…?…..Please help, I want to drive the car soooo badly.

Assuming car was running smoothly with smog gear on and no timing or plug lead order has been changed , then I think you are on the right track with air leaks or weak mixture.
Was the new Weber jetted for your engine and I assume no fuel blockages in main jets, float level correct etc.
Apart from that was the fireball 300 electronic ign timed for the smog setup or the Weber carb, retarded ignition can cause backfiring through the carb, mind you so can duff inlet valves, but not the case if it was happily running before Weber carb.
With your Fireball 3000 ign is it possible to advance timing very slightly with engine running to feel for improvement, though carefully mark original position before hand just in case.
Does fault reduce if choke (cold start) control operated slightly, indicating running weak?
Probably hard with engine running as it is, but sometimes you can trace an air leak around manifold etc. using a rubber tube close to your ear and the other end to locate a hissing noise. Did that one time and the fault was a vacuum leak on the brake servo.
Lovely looking car, I can see why you want to get on the road