my dad gave me a truck and it will not run unless you jump the coil to another power sorce.
so would a relay or fuse be bad?
im new at fords but i am a tech for mitsubishi so i have the capabilitys to work on this truck but i need a boost in the right direction!
thanks for any help!

 

I would try your solenoid sounds like its done for

 

The starter solenoide? i dont think its that?
it turns over and starts fine. it just wont start if i dont hook up the ignition coil pack to another power sorce.
cuz it isnt getting power, thus getting no spark.

so to have the truck running i am getting power from another relay and plugging into the connector that goes to the capassitor that is bolted to the coil pack since it splices to gether from the factory which also leads to the coil.


so my question is what will make the coil get no power? a relay, module or a fuse? if so where at?

 

I do not have an EVTM for a 1990, but here is one for a 1989 and a 1991. Yours is going to be one or the other.

1989 Ignition


1991 Ignition


Courtesy of FordFuelInjection.com

 

I would say Ignition switch or fuse link is bad.
There are no solenoids or relays in this circuit.
The Ignition switch circuit is powered by Fuse link "P" that hooks to the battery side of the starter solenoid.

1990 F-series:




/

 

Your problem could be a blown fusible link.

This is the 88 schematic. 90 should be similar

The fusible link should be from a 10 pin connector which is
located on the driver side fender apron. In the case of
the 88 one side of the fusible link wire will be joined to
a Red/Light Green wire and the other side of the fusible
link will have a White/Light Blue wire which goes to the
positive side of the coil, the TFI Module and also supplies
12 volts to the EEC relay.

If you look on the middle of the driver side plastic wheel
well under the hood you should see two relays. (May be
covered by a piece of plastic).

One is for the fuel pump and one is for the EEC (computer).

The fusible link should be located in that area.

I've circled the fusible link in the schematic. It should have 12 volts
on the fusible link when the ignition is in run or start.

 

I knew Bill would come up with a 1990 EVTM!. With the schematic F150XLT posted and mine it looks like Ford played "pick a letter" with the fuse link functions.

 

F150xlt if you look at my 1990 diagrams above you will see that a 1990 does not have that fuse link there that you circled.

 

I see what you mean, it is called "P" on one page and "M" on the other that I posted.
I do not have the big fold out diagram they copied from to make the 1990 EVTM to see what the fuse link letter should be.

I have often wondered why Ford called so many wires #37 and why they are all yellow.

 

AWESOME!!! thanks so much for the replys!!!

when im not buysy today at work i'll pull it in the shop and check it out and i'll post what i find out!!

 

Make sure it's not just a bad connector @ the coil. My connector was loose, interrupting the power supply, intermittently. I replaced the connector and it's been fine ever since.

 

IT WAS A CONNECTOR!!!
after i got on here and saw the wire diagram i went to town on it!
so i tested for power troughout the whole wire through different spots and found where i stopped getting power then i started ohm ing out the wire and found that the light grey connector on the drivers side plastic fender, well the oinly wire that was corroded was that one wire that leads to the distributor, capasitor and the coil.
so i cleaned it very well and used some electric grease and the truck starts without having to jump the system!!!

 

Thanks for the feedback! Great find.

 

Having the proper documentation always helps.
Nice to hear he's back on the road.