'96 V-6 XLT Intermittent Starting Problem Solved

Now and then, for no apparent reason, my Explorer would crank but not start.
There was no noted pattern -- happened 5-6 times a week intermittently and
randomly with engine hot and cold. No OBD codes stored. Spraying starting
fluid in the air intake while cranking would enable starting. Naturally,
whenever mechanic had the vehicle for diagnosis it would not act up.
Replaced the fuel pump relay on a hunch, and can now definitely hear fuel
pump activate for a few seconds when ignition key's turned to run, before
cranking. Problem seems to be gone, not having reappeared for three weeks.
Len
--
Eliminate "ns" for email address.

The power consumption of the ignition circuit is tiny compared to what the
starter draws. What you are suggesting is highly unlikely.

"Ulysses" /> wrote in message
...
> I had the same problem on my '97 4.0L V6. I removed and cleaned the
> crankcase position sensor connector (bottom front of
> engine). I also replaced the battery. I'm pretty sure it was just the
> battery that was the problem: enough power to crank the engine
> but not enough to make a spark. I guess the computer decides that it's
> better to leave you stranded where you are than leave you
> stranded where you are going.

"Len Krauss" > wrote in message
. ..
> Now and then, for no apparent reason, my Explorer would crank but not
start.
> There was no noted pattern -- happened 5-6 times a week intermittently and
> randomly with engine hot and cold. No OBD codes stored. Spraying starting
> fluid in the air intake while cranking would enable starting. Naturally,
> whenever mechanic had the vehicle for diagnosis it would not act up.
> Replaced the fuel pump relay on a hunch, and can now definitely hear fuel
> pump activate for a few seconds when ignition key's turned to run, before
> cranking. Problem seems to be gone, not having reappeared for three weeks.
> Len
> --
> Eliminate "ns" for email address.
>
>

I had the same problem on my '97 4.0L V6. I removed and cleaned the
crankcase position sensor connector (bottom front of engine). I also
replaced the battery. I'm pretty sure it was just the battery that was the
problem: enough power to crank the engine but not enough to make a spark. I
guess the computer decides that it's better to leave you stranded where you
are than leave you stranded where you are going.

I suggest making sure your battery connections are clean and tight and check
the cells with a hydrometer. I suspect you will find one or two low cells.
Car batteries seem to have a habit of being OK and then suddenly dying
(right about at the end of the warranty period). BTW that particular
battery is so bad now it will not accept a charge at all.

"Happy Traveler" > wrote in message
. ..
> The power consumption of the ignition circuit is tiny compared to what the
> starter draws. What you are suggesting is highly unlikely.
>
> "Ulysses" /> wrote in message
> ...
> > I had the same problem on my '97 4.0L V6. I removed and cleaned the
> > crankcase position sensor connector (bottom front of
> > engine). I also replaced the battery. I'm pretty sure it was just the
> > battery that was the problem: enough power to crank the engine
> > but not enough to make a spark. I guess the computer decides that it's
> > better to leave you stranded where you are than leave you
> > stranded where you are going.
>
>

My understanding is that a "bad" crankcase postiton sensor (or sensor
connection) will cause a "no spark" condition because the computer doesn't
know the position of the crankcase so it basically says "to hell with it."
When I checked my sensor connection it looked like it could use some
cleaning but didn't really look all that bad. I surmised that the problem
was probably not the sensor connection but the battery. The battery was
definately bad. Having a system that would decide that it's OK to crank the
engine but not allow spark due to a slight decrease in available battery
voltage does not seem like a good idea to me and I certainly don't like it
but given my experience with other kinds of computers it did not seem
impossible or unlikely to me, just unreasonble. From what you are saying
then it probably was a dirty connection on the sensor. It was my #1 suspect
partly due to it's exposure to the elements.

In any case the problem has not returned. :-)

"Len Krauss" > wrote in message
. ..
> Now and then, for no apparent reason, my Explorer would crank but not
> start.
> There was no noted pattern -- happened 5-6 times a week intermittently and
> randomly with engine hot and cold. No OBD codes stored. Spraying starting
> fluid in the air intake while cranking would enable starting. Naturally,
> whenever mechanic had the vehicle for diagnosis it would not act up.
> Replaced the fuel pump relay on a hunch, and can now definitely hear fuel
> pump activate for a few seconds when ignition key's turned to run, before
> cranking. Problem seems to be gone, not having reappeared for three weeks.
> Len

Try this simple test - Before actually starting the truck, switch the
ignition switch from off to run three or four times (not to start). Each
time you switch to run, pause for a count or two to allow the fuel pump to
run. After the third or fourth switch to run, try starting the truck. If it
always starts up promptly, then chances are you problem is either a failed
check valve or a leaky injector. If it is a leaky injector you should
occasionally get a cloud of black smoke when the truck starts, otherwise it
is probably the check valve in the pump assembly (i.e. fix = new fuel pump).
You could get much the same indication by checking the fuel pressure after
the truck sets for an extended period.

Ed

"Happy Traveler" > wrote in message
. ..
> The power consumption of the ignition circuit is tiny compared to what the
> starter draws. What you are suggesting is highly unlikely.

If you have a weak battery, the system voltage can drop so low when you are
trying to start the vehcile that the PCM doesn't perform properly. Modern
starters will run at a much lower voltage than in the old days. However,
under these conditions they draw a lot of current, which knocks the system
voltage way down.

Ed


> "Ulysses" /> wrote in message
> ...
>> I had the same problem on my '97 4.0L V6. I removed and cleaned the
>> crankcase position sensor connector (bottom front of
>> engine). I also replaced the battery. I'm pretty sure it was just the
>> battery that was the problem: enough power to crank the engine
>> but not enough to make a spark. I guess the computer decides that it's
>> better to leave you stranded where you are than leave you
>> stranded where you are going.
>
>

Since I was in a situation where I could not reproduce the fault in any
predictable manner, I read about others' experiences on other Explorer
forums. The top culprit and my first "shot-in-the dark" was the fuel pump
relay. At $10 it was cheap to try. My next item would have been the
crankshaft position sensor. But the relay fixed the problem.

This may not be an elegant way to do trouble-shooting, but if you can't
reproduce the
trouble and have no fault codes set, it seems reasonable to try some low
cost fixes that have been reported by others.
Len


--
Eliminate "ns" for email address.
"Ulysses" /> wrote in message
...
>
> "Happy Traveler" > wrote in message
> . ..
> > The power consumption of the ignition circuit is tiny compared to what
the
> > starter draws. What you are suggesting is highly unlikely.
> >
> > "Ulysses" /> wrote in message
> > ...
> > > I had the same problem on my '97 4.0L V6. I removed and cleaned the
> > > crankcase position sensor connector (bottom front of
> > > engine). I also replaced the battery. I'm pretty sure it was just
the
> > > battery that was the problem: enough power to crank the engine
> > > but not enough to make a spark. I guess the computer decides that
it's
> > > better to leave you stranded where you are than leave you
> > > stranded where you are going.
> >
> >
>
> My understanding is that a "bad" crankcase postiton sensor (or sensor
> connection) will cause a "no spark" condition because the computer doesn't
> know the position of the crankcase so it basically says "to hell with it."
> When I checked my sensor connection it looked like it could use some
> cleaning but didn't really look all that bad. I surmised that the problem
> was probably not the sensor connection but the battery. The battery was
> definately bad. Having a system that would decide that it's OK to crank
the
> engine but not allow spark due to a slight decrease in available battery
> voltage does not seem like a good idea to me and I certainly don't like it
> but given my experience with other kinds of computers it did not seem
> impossible or unlikely to me, just unreasonble. From what you are saying
> then it probably was a dirty connection on the sensor. It was my #1
suspect
> partly due to it's exposure to the elements.
>
> In any case the problem has not returned. :-)
>
>

"Len Krauss" > wrote in message
. ..
> Since I was in a situation where I could not reproduce the fault in any
> predictable manner, I read about others' experiences on other Explorer
> forums. The top culprit and my first "shot-in-the dark" was the fuel pump
> relay. At $10 it was cheap to try. My next item would have been the
> crankshaft position sensor. But the relay fixed the problem.
>
> This may not be an elegant way to do trouble-shooting, but if you can't
> reproduce the
> trouble and have no fault codes set, it seems reasonable to try some low
> cost fixes that have been reported by others.
> Len
>

The first thing I did was go buy a fuel pump gauge and check the fuel
pressure. That tested OK on mine. Next I checked for spark which took some
time waiting for the engine to misbehave again. I had no spark. I checked
the voltage at the coils and a bunch of other stuff and everything tested
OK.

I hope your new relay solves the problem.

BTW you can get your battery load-tested for free at many auto parts stores.


>
> --
> Eliminate "ns" for email address.
> "Ulysses" /> wrote in message
> ...
> >
> > "Happy Traveler" > wrote in message
> > . ..
> > > The power consumption of the ignition circuit is tiny compared to what
> the
> > > starter draws. What you are suggesting is highly unlikely.
> > >
> > > "Ulysses" /> wrote in message
> > > ...
> > > > I had the same problem on my '97 4.0L V6. I removed and cleaned the
> > > > crankcase position sensor connector (bottom front of
> > > > engine). I also replaced the battery. I'm pretty sure it was just
> the
> > > > battery that was the problem: enough power to crank the engine
> > > > but not enough to make a spark. I guess the computer decides that
> it's
> > > > better to leave you stranded where you are than leave you
> > > > stranded where you are going.
> > >
> > >
> >
> > My understanding is that a "bad" crankcase postiton sensor (or sensor
> > connection) will cause a "no spark" condition because the computer
doesn't
> > know the position of the crankcase so it basically says "to hell with
it."
> > When I checked my sensor connection it looked like it could use some
> > cleaning but didn't really look all that bad. I surmised that the
problem
> > was probably not the sensor connection but the battery. The battery was
> > definately bad. Having a system that would decide that it's OK to crank
> the
> > engine but not allow spark due to a slight decrease in available battery
> > voltage does not seem like a good idea to me and I certainly don't like
it
> > but given my experience with other kinds of computers it did not seem
> > impossible or unlikely to me, just unreasonble. From what you are
saying
> > then it probably was a dirty connection on the sensor. It was my #1
> suspect
> > partly due to it's exposure to the elements.
> >
> > In any case the problem has not returned. :-)
> >
> >
>
>