>>
>
>My 87 3.9 V6 is giving me fits: It suddendly lost about 50% power, and
stumbles, and is sometimes hard to start when hot.
>
>Parts replaced: plugs,wires, front fuel filter, PCV, rotor, dist cap, O2
sensor.
>
>Have clamped off vac hoses one at a time at carb/manifold, no change.
>
>Hooked up oscilloscope to O2 and carb mixture solenoid. Observations:
>
>First 60 seconds after warm start: O2 near 0 volts, but has spikes. O2 will
rise if I simulate choke by obstructing air intake with my hand. Solenoid
waveform is 20% low, 80% hi. Repeats every 100 milliseconds.
>
>After 60 seconds: Same symptoms except duty cycle changes to 2% low, 98%
hi. RPM drops a little. Disconnecting O2 and/or solenoid harness has no effect.
>
>I did check to make sure the O2 signal makes it up to the computer. It does.
>
>Any ideas? I'm getting desperate.
>
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:07:48 EDT