'88 LX 5.0 not running after sitting (long)

I have a problem that has me a bit perplexed...

Today a friend of mine and I started up two 5.0 cars that sat in a field for
the last few months or so, waiting for the spring thaw. Both cars are as
stock as you can find 'em, and ran with no problems when parked. The one,
an '85 GT 5.0 CFI AOD fired right up after a battery charge. Not a problem.

The other, an '88 LX 5.0 SEFI 5-speed, didn't want to run. At all, not
cold, not warm, nothing. It didn't need a charge, but immediately upon
start up, it sputtered and died. It won't hold an idle. It doesn't seem to
rev up at all when hitting the throttle, but pumping it was ok and it would
get to almost 2500RPM with a quick 10%-0 repeated pumping cycle. Hitting
the throttle to the floor made it just slow to a sure stop every time, like
it only wanted to rev when the throttle plate was closing or closed.
Backfires or afterfires (not sure if it was burning up in the cats or in the
intake) were common during this pumping, especially when going more like
75%-0 continuously.

Grabbed some tools and took a look. I didn't have my computer scanning
tools, and the '88 didn't have a CEL, so I don't know if it was throwing a
code. That's for the next adventure.

First, added some dry gas mixed with a fresh couple gallons of 93 octane.
Both cars sat the same length of time, but maybe one had questionable gas.
This did nothing.

Checked all the wires... they're fine and connected. Pulled the cap, and it
was a little corroded, so we cleaned it up a bit. Still no change.

Pulled the IAC plug, and it actually held a 500RPM idle. I was shocked. By
my deductions, it was getting too much air for the fuel it was getting.
Putting a fuel pressure gauge on the schrader valve showed 30PSI at this
idle, and the number would fluctuate with the throttle, but not drop below
30.

I put a timing light on the coil wire at 500RPM, just to see. There was a
miss every now and then, showed by the light and the stutter of the engine,
but it was fairly constant. Pumping the throttle to rev it up, there were
no breaks. Same with using plug wire #1. Even with the full-throttle from
2500RPM, the light never missed, but the engine was slowing fast.

Timing at 500RPM without the SPOUT (yes, it ran that way too as long as the
IAC was disconnected) was around 14 or 15 degrees, running 93 octane gas.

My theories at this point (without a computer scan) are...

O2 sensors wouldn't matter because it did this cold, well before the sensors
would be used for fuel trim anyway

MAF sensor is N/A - this is a speed density car. The only other tools used
to map the fuel are the RPM, TPS, and MAP. The hall effect sensor in the
distributor could be bad, the TPS could be way off, the MAP could have
problems, could be a vacuum leak (though none was heard), or injectors could
be plugged.

The car hasn't been tuned in a while, so my friend will throw a cap, rotor,
plugs, and wires on it... but I have a feeling it won't help. The light
shouldn't light unless the plug fires or is shorted together somehow, and
the 500 RPM idle was mostly smooth, indicating a fire on all 8.

Any other suggestions or things that I'm missing? We have a spare
distributor out of a known-good engine, new 19# injectors in a Ford box, and
MAP sensors are pretty cheap. I just hate throwing parts at a problem, even
if the parts are free.

TIA,

JS

In addition to the usual suspects (plugs, secondary wires, dizzy cap and
rotor) you mentioned, make sure there's a healthy spark from the ignition
coil output.

--
Mike
93 Cobra

In article <g%21e.24186$qN3.2098@trndny01>, "JS" > wrote:

> I have a problem that has me a bit perplexed...
>
> Today a friend of mine and I started up two 5.0 cars that sat in a field for
> the last few months or so, waiting for the spring thaw. Both cars are as
> stock as you can find 'em, and ran with no problems when parked. The one,
> an '85 GT 5.0 CFI AOD fired right up after a battery charge. Not a problem.
>
> The other, an '88 LX 5.0 SEFI 5-speed, didn't want to run. At all, not
> cold, not warm, nothing. It didn't need a charge, but immediately upon
> start up, it sputtered and died. It won't hold an idle. It doesn't seem to
> rev up at all when hitting the throttle, but pumping it was ok and it would
> get to almost 2500RPM with a quick 10%-0 repeated pumping cycle. Hitting
> the throttle to the floor made it just slow to a sure stop every time, like
> it only wanted to rev when the throttle plate was closing or closed.
> Backfires or afterfires (not sure if it was burning up in the cats or in the
> intake) were common during this pumping, especially when going more like
> 75%-0 continuously.
>
> Grabbed some tools and took a look. I didn't have my computer scanning
> tools, and the '88 didn't have a CEL, so I don't know if it was throwing a
> code. That's for the next adventure.
>
> First, added some dry gas mixed with a fresh couple gallons of 93 octane.
> Both cars sat the same length of time, but maybe one had questionable gas.
> This did nothing.
>
> Checked all the wires... they're fine and connected. Pulled the cap, and it
> was a little corroded, so we cleaned it up a bit. Still no change.
>
> Pulled the IAC plug, and it actually held a 500RPM idle. I was shocked. By
> my deductions, it was getting too much air for the fuel it was getting.
> Putting a fuel pressure gauge on the schrader valve showed 30PSI at this
> idle, and the number would fluctuate with the throttle, but not drop below
> 30.
>
> I put a timing light on the coil wire at 500RPM, just to see. There was a
> miss every now and then, showed by the light and the stutter of the engine,
> but it was fairly constant. Pumping the throttle to rev it up, there were
> no breaks. Same with using plug wire #1. Even with the full-throttle from
> 2500RPM, the light never missed, but the engine was slowing fast.
>
> Timing at 500RPM without the SPOUT (yes, it ran that way too as long as the
> IAC was disconnected) was around 14 or 15 degrees, running 93 octane gas.
>
> My theories at this point (without a computer scan) are...
>
> O2 sensors wouldn't matter because it did this cold, well before the sensors
> would be used for fuel trim anyway
>
> MAF sensor is N/A - this is a speed density car. The only other tools used
> to map the fuel are the RPM, TPS, and MAP. The hall effect sensor in the
> distributor could be bad, the TPS could be way off, the MAP could have
> problems, could be a vacuum leak (though none was heard), or injectors could
> be plugged.
>
> The car hasn't been tuned in a while, so my friend will throw a cap, rotor,
> plugs, and wires on it... but I have a feeling it won't help. The light
> shouldn't light unless the plug fires or is shorted together somehow, and
> the 500 RPM idle was mostly smooth, indicating a fire on all 8.
>
> Any other suggestions or things that I'm missing? We have a spare
> distributor out of a known-good engine, new 19# injectors in a Ford box, and
> MAP sensors are pretty cheap. I just hate throwing parts at a problem, even
> if the parts are free.
>
> TIA,
>
> JS

"JS" > wrote in message news:g%21e.24186$qN3.2098@trndny01...
> I have a problem that has me a bit perplexed...
>
> Today a friend of mine and I started up two 5.0 cars that sat in a field
for
> the last few months or so, waiting for the spring thaw. Both cars are as

The way it is running (so to speak) sounds like a weak coil. I have seen
most of the symptoms you described on a number of cars: won't rev, idles
okay sometimes, back firing (I've never heard it called after firing),
missing, etc.

I'd make the coil swap before digging into the spark plugs.
--
-Donald in Austin

"The other Donald" > wrote in message
...
>
> "JS" > wrote in message news:g%21e.24186$qN3.2098@trndny01...
>> I have a problem that has me a bit perplexed...
>>
>> Today a friend of mine and I started up two 5.0 cars that sat in a field
> for
>> the last few months or so, waiting for the spring thaw. Both cars are as
>
> The way it is running (so to speak) sounds like a weak coil. I have seen
> most of the symptoms you described on a number of cars: won't rev, idles
> okay sometimes, back firing (I've never heard it called after firing),
> missing, etc.
>
> I'd make the coil swap before digging into the spark plugs.
> --
> -Donald in Austin

Donald and Mike,

Thanks for the suggestion of the coil. After you mentioned this, I
remembered a battle I had with an '88 GT that I thought for sure was the
distributor, and it turned out to be the TFI coil.

My friend swapped the coil with one in a '90 that had worked when we pulled
the car apart a few years ago. No help. He went out and bought a new coil,
thinking that perhaps that one was bad too, but to no avail.

We're still at a loss. I don't think he's had time to get into the plugs
due to Easter rapidly approaching.

Thanks again for your help, and have a good Easter holiday if you're so
inclined.

JS

The symptoms sound very similar to what I was experiencing in my 88GT when
the fuel pump started going out.

"JS" > wrote in message news:wAu1e.44841$db6.16499@trndny02...
>
> "The other Donald" > wrote in message
> ...
> >
> > "JS" > wrote in message
news:g%21e.24186$qN3.2098@trndny01...
> >> I have a problem that has me a bit perplexed...
> >>
> >> Today a friend of mine and I started up two 5.0 cars that sat in a
field
> > for
> >> the last few months or so, waiting for the spring thaw. Both cars are
as
> >
> > The way it is running (so to speak) sounds like a weak coil. I have seen
> > most of the symptoms you described on a number of cars: won't rev, idles
> > okay sometimes, back firing (I've never heard it called after firing),
> > missing, etc.
> >
> > I'd make the coil swap before digging into the spark plugs.
> > --
> > -Donald in Austin
>
> Donald and Mike,
>
> Thanks for the suggestion of the coil. After you mentioned this, I
> remembered a battle I had with an '88 GT that I thought for sure was the
> distributor, and it turned out to be the TFI coil.
>
> My friend swapped the coil with one in a '90 that had worked when we
pulled
> the car apart a few years ago. No help. He went out and bought a new
coil,
> thinking that perhaps that one was bad too, but to no avail.
>
> We're still at a loss. I don't think he's had time to get into the plugs
> due to Easter rapidly approaching.
>
> Thanks again for your help, and have a good Easter holiday if you're so
> inclined.
>
> JS
>
>

Years ago my 88GT did this exact thing you describe and I too was at a
loss of ideas through process of elemination. I thought I had bad gas
and I went through the same things you describe. Anyway to make a long
story short, while car was at idle I unplugged the TPS and it ran
smooth (at idle) I put a new TPS on and it ran fine. Before it was
backfiring through the intake manifold.





On Mon, 28 Mar 2005 07:21:35 GMT, "ironrod" >
wrote:

>The symptoms sound very similar to what I was experiencing in my 88GT when
>the fuel pump started going out.
>
>"JS" > wrote in message news:wAu1e.44841$db6.16499@trndny02...
>>
>> "The other Donald" > wrote in message
>> ...
>> >
>> > "JS" > wrote in message
>news:g%21e.24186$qN3.2098@trndny01...
>> >> I have a problem that has me a bit perplexed...
>> >>
>> >> Today a friend of mine and I started up two 5.0 cars that sat in a
>field
>> > for
>> >> the last few months or so, waiting for the spring thaw. Both cars are
>as
>> >
>> > The way it is running (so to speak) sounds like a weak coil. I have seen
>> > most of the symptoms you described on a number of cars: won't rev, idles
>> > okay sometimes, back firing (I've never heard it called after firing),
>> > missing, etc.
>> >
>> > I'd make the coil swap before digging into the spark plugs.
>> > --
>> > -Donald in Austin
>>
>> Donald and Mike,
>>
>> Thanks for the suggestion of the coil. After you mentioned this, I
>> remembered a battle I had with an '88 GT that I thought for sure was the
>> distributor, and it turned out to be the TFI coil.
>>
>> My friend swapped the coil with one in a '90 that had worked when we
>pulled
>> the car apart a few years ago. No help. He went out and bought a new
>coil,
>> thinking that perhaps that one was bad too, but to no avail.
>>
>> We're still at a loss. I don't think he's had time to get into the plugs
>> due to Easter rapidly approaching.
>>
>> Thanks again for your help, and have a good Easter holiday if you're so
>> inclined.
>>
>> JS
>>
>>
>