Bunny Boy

1989 Ford F-250 7.3L V8 diesel. 220k miles (160k on engine)

Engine starts fine when it is cold. Runs good. When it has been running
a while and the engine is hot, then after being parked 10 minutes or so
it won't start. It cranks just fine but won't fire up. Spraying a
little WD-40 in the air intake makes it fire up every time.

Any clues as to what could cause this, or suggested diagnostics that
could reveal the cause?

Thanks,
Bunny

Derrick Hudson

On 1 Aug 2005 12:39:04 -0700, Bunny Boy wrote:
> 1989 Ford F-250 7.3L V8 diesel. 220k miles (160k on engine)
>
> Engine starts fine when it is cold. Runs good. When it has been running
> a while and the engine is hot, then after being parked 10 minutes or so
> it won't start. It cranks just fine but won't fire up. Spraying a
> little WD-40 in the air intake makes it fire up every time.
>
> Any clues as to what could cause this, or suggested diagnostics that
> could reveal the cause?

This sounds a lot like vapor lock. Fuel injected vehicles with an
electric fuel pump don't exhibit this phenomenon. I don't know if
diesel engines were ever affected, or if your '89 has electronic
injection. I know that the gas engines after '86 were EFI.

HTH,
-D

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Dave D

"Bunny Boy" <frdnkr@yahoo.com> wrote in message
news:1122925144.587144.117740@g49g2000cwa.googlegroups.com...
> 1989 Ford F-250 7.3L V8 diesel. 220k miles (160k on engine)
>
> Engine starts fine when it is cold. Runs good. When it has been running
> a while and the engine is hot, then after being parked 10 minutes or so
> it won't start. It cranks just fine but won't fire up. Spraying a
> little WD-40 in the air intake makes it fire up every time.
>
> Any clues as to what could cause this, or suggested diagnostics that
> could reveal the cause?
>
> Thanks,
> Bunny

Try this - carry some ice with you in a container, after the engine is hot
and the "no start" condition exists, put a double handful or so of
ice,wrapped in an old shop cloth, towel or whatever, on top of your
injection pump. Leave it sit for a couple of minutes and then try to start
it. If it starts, the problem is vaporized fuel in the injection pump, if
not then good luck....

Dave D

>

Bunny Boy

Hey Dave:

I left the ice on for ten minutes, and it started right up!

So where do I go from here?

SnoMan

"" wrote:
> "Bunny Boy" <frdnkr@yahoo.com> wrote in message
> news:1122925144.587144.117740@g49g2000cwa.googlegroups.com...
> > 1989 Ford F-250 7.3L V8 diesel. 220k miles (160k on engine)
> >
> > Engine starts fine when it is cold. Runs good. When it has
> been running
> > a while and the engine is hot, then after being parked 10
> minutes or so
> > it won't start. It cranks just fine but won't fire up.
> Spraying a
> > little WD-40 in the air intake makes it fire up every time.
> >
> > Any clues as to what could cause this, or suggested
> diagnostics that
> > could reveal the cause?
> >
> > Thanks,
> > Bunny
>
> Try this - carry some ice with you in a container, after the
> engine is hot
> and the "no start" condition exists, put a double handful or
> so of
> ice,wrapped in an old shop cloth, towel or whatever, on top of
> your
> injection pump. Leave it sit for a couple of minutes and then
> try to start
> it. If it starts, the problem is vaporized fuel in the
> injection pump, if
> not then good luck....
>
> Dave D
>
> >

THere are not big suprizes here, the engine is not getting fuel. It is
either in the injection pump or the fuel pump feeding the pump. Also
check fuel filters and check water drain for water in fuel that is
boiling off to steam in fuel/pump when engine is hot.

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SnoMan

"Bunny Boy" wrote:
>Hey Dave:
>
>I left the ice on for ten minutes, and it started right up!
>
>So where do I go from here?

Did you check for water in the fuel boiling off (which the ice would
condense)

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Bunny Boy

I'm really unclear on this. I put the icepack on the top of the
injection pump, not the fuel filter. I don't see how condensing water
that was steam in the injection pump would make it start. Wouldn't you
just have a water in fuel condition then? And once it's started, it
runs fine. Also, why would a spray of WD-40 make it start?

IowaHarry

"Bunny Boy" <frdnkr@yahoo.com> wrote in news:1123209237.516971.218670
@o13g2000cwo.googlegroups.com:

> I'm really unclear on this. I put the icepack on the top of the
> injection pump, not the fuel filter. I don't see how condensing water
> that was steam in the injection pump would make it start. Wouldn't you
> just have a water in fuel condition then? And once it's started, it
> runs fine. Also, why would a spray of WD-40 make it start?
>

Check for cracked fittings on the fuel rail. I experienced this on a 91
7.3. The kit for all the fittings, new hoses, hose clamps and O-rings was
about $38. The evidence also included fuel smell from engine compartment as
there was a leak.

good luck, IowaHarry

SnoMan

"Bunny Boy" wrote:
>I’m really unclear on this. I put the icepack on the top of the
>injection pump, not the fuel filter. I don’t see how condensing
>water
>that was steam in the injection pump would make it start.
>Wouldn’t you
>just have a water in fuel condition then? And once it’s
>started, it
>runs fine. Also, why would a spray of WD-40 make it start?

If there is water in the fuel and it boils off in the hot pump, it
will greatly expand and displace the fuel until it is purged with the
engine running. When you ice it the water condenses and the water
vapor lock is lost. Just a few drops of water is all it would take
too.

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Bill M

Just to be outside the box, I'll suggest that your fuel has excessive
alcohol in it. Alcohol allows water to mix with fuel, and might be found in
fuel. The cure? A few drops of water. Crazy, huh?

Bill M


"Bunny Boy" <frdnkr@yahoo.com> wrote in message
news:1122925144.587144.117740@g49g2000cwa.googlegroups.com...
> 1989 Ford F-250 7.3L V8 diesel. 220k miles (160k on engine)
>
> Engine starts fine when it is cold. Runs good. When it has been running
> a while and the engine is hot, then after being parked 10 minutes or so
> it won't start. It cranks just fine but won't fire up. Spraying a
> little WD-40 in the air intake makes it fire up every time.
>
> Any clues as to what could cause this, or suggested diagnostics that
> could reveal the cause?
>
> Thanks,
> Bunny
>