I have a 1989 ford f350 460 efi we have had a continuing problem. This thing wants to start rich it will start then die start and run sluggish then settle down it still acts like it is running rich at idle. Also it doesn't start like most efi Fords you know usually a high idle for a few seconds and then settle down to a nice idle speed. I have replaced the o2 sensor the act sensor and cleaned the air bypass valve there are no engine codes. the timimg is at 10 degrees with pip pulled. This is a new engine and I don't want to hurt it by running rich. the old engine had the same problem. What else should I check? It almost acts like there is some fuel leaking into the system when it is turned off like an old carb system would do. also replaced all the injectors when we had the engine rebuilt.

 

Whats the fuel pressure reading at start-up. Maybe you have a bad regulator.

Chris

79 F-150 Lariat: Long-bed, 2wd, 460 (intake, headers, cam, early heads), C-6 (shift kit)
79 Mustang: 460 swap under way, balanced rotating assembly, forged pistons, truck rods, c-8 heads ported, Lunati solid lifter cam, more stuff...
98 Chevy Silverado ext. cab 4x4 (work truck)
95 Lexus SC300 (wife's baby)

 

The fuel pressure when running is 38 lbs. Will check it again at start up, What should I see when the pump runs before starting. I know that engine vacume causes the regulator to hold down fuel pressure.

 

Check the TPS with meter