Starting off I have a '85 F150 4.9L 300 V6.

First post here. Been reading for a few days trying to solve this problem and thought I'd post to try and get some specific help.

I got this old beat-up truck about a week ago for cheap and I knew it would need some work done but it was running. I drove it home, and proceeded to replace the gasket for the valve cover, after I replaced the valve cover, the air intake housing, the few hoses I moved, and hooked the battery back up, and now it won't start. I have power to the truck, and it turns over when I turn the key but it won't fire up.

I checked the carburetor and when I opened the throttle gas is sprayed into it, the owner said they recently replaced the starter, so now I'm wondering if it's something to do with the spark plugs or something else. I'm pretty confused right now because it literally ran a few days ago.

 

Welcome to the group!
First thing I would do with a non-starting engine, after making sure it rotates, has oil and coolant, is spray starting fluid into the carb and see what it does. If it starts then shuts off then you have a fuel delivery issue. If it doesn't even want to try to start then I would suspect a spark issue. You are on the right track with putting fuel down the carb to check.

The way I check for spark:
1) Pull the coil wire at the distributor cap and put an old spark plug (or a spark tester available on Amazon) in it to see if there's spark (make sure the threads or end of tester are touching a clean metal surface. If no spark then you need to check for power at the coil. If no power check the fuse. If the fuse is good then you have a bad connection or broken / disconnected wire going to the coil. If you do have power at the coil I would suspect a bad coil but it could also be that wire, if you have another wire handy try it with that wire.
2) If you do have spark at the coil then you need to do the same at the spark plugs.
3) If no spark at the plugs, check the cap and rotor for corrosion / burnt contacts. You can clean up a cap and rotor but you'll want to replace soon.
4) If the cap and rotor look clean pull and check the spark plugs. If the plugs are fouled with anything clean them and double check the gap and if they look clean I'd replace the wires. Side note: if you need to replace the wires you really should replace the cap & rotor along with the spark plugs as well.

That's my basic how-to and I'm sure someone will chime in and clean up my description and add a couple of things.

 

Hell yeah I really appreciate that! My next step was to replace the distributor cap, rotor, ignition module, spark plugs and wires and figured that should give me a good start at the problem.

 

I would not waste any money on a ignition module yet. If this truck hasn't been changed over, it has the computer system on it with the TFI distributor in it. And a whole bunch of wiring and junk on it. If you want to mess with it and troubleshoot some things that is fine. But if you want to throw parts at it, I would throw a HEI distributor and a Amazon non-computer carb on it. Then you will have a simple engine that does not need the computer and all those wires to run.

 

If I swap to an HEI distributor and the non-computer carb are there any other important parts into take out or replace?

 

I kinda figured someone would jump in here with a better answer. Thanks Dave. As I was typing my response this morning I kept thinking there was something about the distributor on these trucks but I didn't want to say the wrong thing...

 

I was under the hood replacing the spark plugs and I noticed this wire that was broken on one end and not connected to anything. Was wondering if you guys knew what it might be? It was sitting on the passenger side near the battery.

 

I can't make out what the wire is.

If you get the new distributor and carb, you can get it running good. Then you can get under the dash and over the transmission hump under the dash will be the computer. You can unplug that large wiring plug, take the computer out, and then knock the large rubber plug out of the firewall and fish that large wiring plug though the firewall. You can put the plug back in and use something to plug the hole to keep the mice out, and then you can take the plug and start pulling on it. You will find wires going to sensors you do not need, solenoids you do not need, etc. Eventually you will be able to take that wiring plug out with all that gob of wires with it.

 

I appreciate the help Dave! I'm going to swap out the distributor and carb, and remove all the junk like you said and I'll update you guys !

 

So with this new distributor that has a single 12 volt wire, is there a recommended way wire this? Like where do I plug it into haha.

 

Find the ignition coil you are using now. Unplug the smaller wires from it, one of them will be white with lightblue dots. Cut this wire, it is the one wire that you will hook to the new distributor.