Ford Probe '97 4-cyl brief power loss

Hello,

My Ford Probe recently (past 2 weeks) started showing some problems
with intermittent brief power losses. The only thing I notice is that
while driving the RPM indicator drops and the radio resets itself. A
split-second later RPMs are up to where they were before and the radio
starts playing again. This has happened 3 times today with 40 minutes
between the incidents, at low and high speeds.

Any ideas what might be causing this ?

My guess is that you are getting a momentary disconnect of electrical power,
maybe due to a bad ground, battery connection, etc. This supports a loss of
power, radio reset, etc.

Hmm, I can see that if it happened without the engine running. But if
the alternator is spinning then doesn't that mean there are essentially
two power sources (alternator and battery) ? So with a bad ground from
either one there should still be another connection or not ?
Thanks.

"grubertm" > wrote in message
oups.com...
> Hmm, I can see that if it happened without the engine running. But if
> the alternator is spinning then doesn't that mean there are essentially
> two power sources (alternator and battery) ? So with a bad ground from
> either one there should still be another connection or not ?

Lets not limit it just to a bad ground, but expand it to a bad connection of
some type.
This is what will cause a radio reset condition, and supports temporary
power loss as well.

If you can find a schematic on this car, you might be able to narrow down
the circumstances that would lead to a temporary loss of voltage.

If it were I, I would check and clean all ground terminals, battery
terminals, etc and make sure connections were good as a starter.

'Intermittents' like this can be hell to find, at times.

Well it has not ocurred again in the past week so I guess it really was
a simple mistake on my part:
After reconnecting the battery ground terminal I I had tightened the
nut but did not tighten it all the way. Now I applied some more torque
and the problem has disappeared.

grubertm wrote:
> Well it has not ocurred again in the past week so I guess it really was
> a simple mistake on my part:
> After reconnecting the battery ground terminal I I had tightened the
> nut but did not tighten it all the way. Now I applied some more torque
> and the problem has disappeared.

Well, there you go! The alternator only generates voltage potential
above ground. Therefore, even though it would supply + voltage to a
loose battery positive terminal, a loose battery ground terminal would
still cause an open circuit in the entire system (in reference to
battery ground, which is the true source of electron flow; your chassis
is just along for the ride).

Glad you found the cause.

Toyota MDT in MO