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Old December 9th 04, 01:49 PM
Neil Nelson
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In article >,
Mark > wrote:

> Hi,
> I am having a problem with a 1995 Ford Aerostar, 3.0L, 130k miles. The
> engine will crank, but it won't start. I'm getting 39 lbs of fuel
> pressure at the fuel rail. I checked one plug wire, and it is getting
> spark. Can a bad hall effect sensor give me these symptoms? If so, can
> this be changed without removing the distributor from the engine?
> Thanks in advance for any help,


Check for rot and corrosion at every spark plug *wire* terminal,
that means both ends of all six plug wires AND the coil wire.
Just because you have spark at one plug doesn't mean you have it
at the other five. Odds are, you'll find the coil terminal and
coil wire terminal caked with corrosion either at the coil, at
the distributor cap or both. (Fords are lousy for this)
Check for injector pulse at one or two injectors, this can be
done with a 12 volt test light substituted in place of the
injector *at* the injector. A #194 bulb (side marker) with the
contacts bent straight should be a very close fit to the injector
plug and will not load the circuit enough to cause any damage
(appx 1/4 amp).

To replace the Hall switch, you'd need to remove the distributor,
and then remove the drive gear on the bottom of the shaft.
if you don't have the proper tools to remove the gear, odds are
you'll break the gear.
I wouldn't say it's impossible, but it would be very unlikely to
have a failed Hall switch and have spark but no signal to the PCM
to signal the injectors.
Chronic Hall switch failures in Fords went away in the late 80s.

Pull a couple of spark plugs, are they wet, dry, black with soot,
worn, wrong part #?
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