Hi im new too all this but from the looks of all everyone here seems great. i was wondering if anyone could help with a little problem. i recently got an 86 f-150 4x4 with a 302. First problem i had, is that the truck, when running and warms up, idles high at 2000 and higher sometimes. any ideas on what might be doing this. Also if it warms up it will not start until it cools off. And last but not least just today the truck will not start. it cranks and has spark but no idea why it still wont start. tested fuel pressure the other night and it was around 40. Thanks for all your help.

 

also wondering if there is a good online store to get a complete wiring harness for my 86 f-150

 

for the high idle it may be a vacuum leak. or iac
the no start when hot- probably a failing ignition module on the distributor.
for it not starting now- you dont know why it "DOES" have spark?
did you test pressure at the rail or before the filter?
and while it was running or while shut off?
is the fuel pump relay clicking? or can you hear the pump at all?

and i dont know about getting the wiring harness.

 

It has spark but will not start. the pressure was tested after the filter while the ignition was on but the engine was not runnin. i have not checked the iac but i know it has good vacuum. thanks for your help.

 

with the engine off it should hold more than 40psi. at the rail at idle it should be at about 30psi minimum. i'd change the fuel filter first. i think that year had 2 filters. they made a line connector to delete the front filter.

 

Reading between the lines here it sounds like you are saying that the fuel pumps may be running all the time the key is on. I say this because if you just turned on the key most of the time the system will not get all the way up to 40 PSI just turning it on.
Try to read the codes from the computer. I think you will find that you can not while it is not starting but you can if it is in the starting mood.
If I am right on both of these then it sounds like you have a bad EEC Computer.

 

im going too replace the fuel filter today and see what happens any points on how too get the pressure out with the truck not being able too start?
Also i am still trying too figure out how too pull the codes.

 

thank you for your help

 

I think you are asking how to check the fuel pressure.
To check the fuel pressure ground pin#6 of the DLC (test connector) with a fuel pressure gauge hooked to the fuel manifold. Then turn on the key and the gauge should read about 42 PSI. The pumps should run all the time the key is on and pin #6 grounded. Remove the ground from pin #6 and the pumps should stop. If does not stop with the key on and the engine not running as said above we have a problem with the fuel pump relay, its wiring or the computer is bad.
The DLC should be on the drivers fender under the hood and under or near the fuel pump relay.

Image of the DLC (test connector):
http://i54.photobucket.com/albums/g9...taLinkConn.jpg

Your fuel system:
http://i54.photobucket.com/albums/g9...FuelSystem.jpg

A 1986 does not have a CEL (check engine light) so you will have to use a test light or a needle type VOM at the DLC.

To check your codes go to this link below:
http://www.broncodata.com/tech/codes.htm

Or get a code reader, here is a good one.
The EQUUS #3145
http://i54.photobucket.com/albums/g9...CodeReader.jpg

 

Try moving the distributor one way or the other while someone cranks it. I just replaced the timing chain in a friend of mine's truck last week. He started it up one day and it cut off, then would not restart. It wanted to run, but just wouldn't fire. Just something else for you to check.