Hey folks, I'm really stumped on this problem. 350 TBI engine, high miles
Symptoms:
-cranks rough, but starts quickly (like initial timing is too high) sometimes, it will kick back instead of starting.
-in park, won't accelerate off idle with heavy throttle application, shudders violently. BUT, it will accelerate normally if running at 1500rpm or more.
-Runs extremely rough and then stalls with EST Bypass disconnected, no matter where you turn the distributor. Timing light drops out randomly.
-with EST bypass connected, the engine will run smoothly anywhere from
0-24degrees timing.
Tests:
-20in Vac steady at idle, 25in steady at 2500RPM
-IGN module tested OK, (swapped in spare just incase, no change)
-pickup coil measures in spec
-ign coil measures in spec
-cap and rotor, plug wires have 5000 miles on them look new.
-injectors have nice uniform pattern.
-plugs are a bit on the black side, just sooty not wet.
-MAP reads 1V at idle and 4.6V with key on engine off.
Why can't I set the base timing? Every time I disconnect the EST bypass she goes dodo.
Regards, Brent