1990 F150 302 no spark sometimes. Help?

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DjE - 20 Jun 2005 09:10 GMT

My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
spark and either not starting or stalling in traffic. I pulled the coil
wire from the dist and I get no spark. Where do I begin to diagnose this
problem?? Are there any common items for this generation of F150 to start
with? I don't know if its linked or not, but sometimes I get a really
low/rough idle. I am thinking that the no spark syndrome and the
intermittent poor idle are related.

Any ideas?

TIA

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David M - 21 Jun 2005 01:11 GMT

> My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
> spark and either not starting or stalling in traffic. I pulled the coil
[quoted text clipped - 7 lines]
>
> TIA

TFI module

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David M (dmacchiarolo)
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Big Al - 21 Jun 2005 01:15 GMT

>> My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
>> spark and either not starting or stalling in traffic. I pulled the coil
[quoted text clipped - 10 lines]
>
> TFI module

It's mounted on the side of the distributor. When you replace it be sure to
use the thermal grease.

Al

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lugnut - 21 Jun 2005 13:30 GMT

>My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
>spark and either not starting or stalling in traffic. I pulled the coil
[quoted text clipped - 7 lines]
>
>TIA

As has been stated, it is probably the TFI module on the
distributor if it always happens when warm. Make sure you
use thermal grease or paste - not dielectric grease. Some
folks think it is the same thing. It is not.

Good luck
Lugnut

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DjE - 22 Jun 2005 02:34 GMT

> My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
> spark and either not starting or stalling in traffic. I pulled the coil
[quoted text clipped - 7 lines]
>
> TIA

I took the old TFI unit off and had it tested at the local parts place.
It came up bad. I have driven around all day in 90+ heat with no
stalling now so I think its all better. Instead of using their
dialectric heat sink grease, I use some of my Arctic Silver heat sink
compound. That will allow better heat transfer to the distributor until
I relocate the module when I pull the dist out to replace the
hall-effect sensor later this week.

Thanks for the help all!

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Art Vandolay - 23 Jun 2005 02:34 GMT

>> My 1990 F150 5.0 4x4 (110K Miles) has this annoying habit of losing all
>> spark and either not starting or stalling in traffic. I pulled the coil
[quoted text clipped - 18 lines]
>
> Thanks for the help all!

Did you replace the coil and distributor with a new one? Try all new
spark plug wires as well. The truck is fifteen years old so it is time
for parts to start to fail on you.

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