911SC 3L 1978 Bad performance when warm

[irmabark]

Car was standing for plus-minus 5 years. Removed and cleaned out fuel tank, refit, fit new fuel pump, new fuel filter. Fit recon fuel distributor, warm-up regulator strip and reset, new plug leads, new injectors. Cold start, no problem, revving-up smoothly, after driving about 4km's starting to back-fire and misfire.
Problematic until cooled down. Main fuel pressure 5.2bar & control pressure 3.7bar. Injectors quantities have been calibrated. Anyone had similar problem?

[timmy2]

Any problems starting it when warm?
Have you set the mixture up with a CO tester?
All vacuum lines new?
New distributor cap and rotor?
Timing settings?

[Scott R]

Really sounds ignition related. Try swapping out to a known good CDI box and run the test again.

[kodioneill]

Sound like a lean mixture problem. Check pop off valve see if it's seated properly. Check for vacuum leaks. Did you check and set mixture if so how ?

[Bob Kontak]

kodioneill is on target. Your control pressure is way too high - for starters. If you knew enough to check the pressures why didn't you know what your pressure operating range was?

3.4 bar is your max warm control pressure at 40C - 104F. That's pretty f**king hot for November.

[Bob Kontak]

[timmy2]

Actually Bob I believe the graph is for Cold control pressures. (As per box beside it)
His Warm control pressure is 0.1 bar higher then what it says in the chart next to the graph.( 3.2-3.6 bar)
His system control pressure should be 4.5 to 5.2 bar car off, pump running.
His readings are at the top end of the scale.
I'd be more interested in the residual pressures when warm and the CO mixture he has.
Also Ignition and timing conditions.

[Bob Kontak]

Yep - I gotta eat shiet on this one. Sorry to the OP for coming off like a jerk. I'm not really, just only when I am. heh heh.