i have a 1985 f150 with the 300 straight six. occasionally it will struggle to turn over especially when it is warmer outside. i replaced the battery, ignition coil, plugs, wires, cap, and rotor. ive gone through all the wiring and re spliced all factory splices checked for damaged wire, lose connections and all and i cant figure it out. any thoughts? thanks

 

Your choke probably isn't working and half of the emissions equipment is probably gone too, so your timing is locked and the computer is making your carburetor run pig rich.

 

It sounds to me like either battery or ground cable problems or a starter problem. Even battery and ground cables that look good can have bad connections between the wire and the connector. I recently had a problem with Dad's truck where it would turn over slowly and not start, but only every once in a while. Luckily I had the hood up when it did it the other day and smoke curled up from the positive battery cable's connection to the solenoid. Sure enough, a close inspection determined that the crimped-on connector wasn't making good connection with the wire - some times. I replaced it and the starting is much faster all the time and I've not had an instance where it cranked slowly.

So, I would check out the connections, not just at the battery and solenoid but between the wire and the terminals, of all the cables:

• Battery to solenoid
• Solenoid to starter
• Battery to engine block

But, if that doesn't do it pull the starter and have it tested at the parts store. What happens is that the bearings (bushings, really) wear and the rotating part, the armature, gets close to the stationary part, the field. But, on a hot day or after the vehicle has been driven quite a while all the parts are hot and have expanded so they actually touch. Usually it isn't enough to keep the starter from turning, but just enough to keep it from turning at full RPM so the engine isn't cranking at full speed and doesn't start.

All these things work together. IOW, when the starter drags, which is what that is called, it pulls more current than normal. More current creates more voltage drop across poor connections, which means the starter doesn't get everything the battery has. So, all of these things need to be in good condition.

 

+1 on what gary said. just recently got done workin on an explorer with this problem. battery was good, starter was weak, so got a new starter. cleaned all connections. still a bugger when warm. pulled the positive fromt he bat to the starter. wicked nasty inside. new positive cable to the starter and startin great. replace the ground,too, just to be safe.

 

yea 1983f150300 the air pump has been removed and the vaccum lines are just cut off for that. and ill try out all the other options and let yall know what i come up with. thanks for yalls help this thing is giving me a headache. but fortunately the engine bay hasent been too hacked up.

 

Being that it's computer controlled, to ever make it run the way it should again, you've got two options.

1) You can try to replace the mission emissions equipment, pull codes from the computer, and correct any other problems that may be present.

2) You can pull a distributor, carburetor, wiring harness, ignition module, and coil from a 1983 or older F-series truck with the Duraspark II electronic ignition, and do the plug-n-play swap to the older non-computerized carburetor.

What kind of gas mileage does the truck get? A properly functioning feedback carburetor should produce around 18 or so mpg's or better.

 

check all the cells in your battery. if they all test good, go with your starter. Living in AZ I can tell you that heat can kill both a starter and a batter almost instantly when they feel like going out.

 

im not getting very good fuel milage at all but its hard to say right now bc i got a small leak in the tank, waiting for my new one to arrive. today i advanced the timing slightly and it seems to crank better. but still have a hestation(like a miss) when accelerating normally. it doest do that if i accelerate harder

i just got a new battery and im having the starter test today and replacing battery cables checking for loose connections.

thanks again for all the help. hopefully i can get it straight and master this engine.

 

Sounds like you may either be running very lean or the accelerator pump isn't set for a strong enough shot at small throttle movement. We'll work on that when you get every thing else sorted out.

 

well i thnk i got the starting issue handled timing advance, replaced battery to solinoid, solinoid to starter battery to starter. now working on getting the hestation problem fixed. again thanks for all the help

 

Remind me what carb you have. Makes a diff how to adjust the acc pump.

 

stock single barrel carb feedback style

 

Out of my league. It sounds like you are lean and that the accelerator pump isn't squirting quite enough on light acceleration. On essentially any other carb I'd know what to do to change the pump's output, but don't on the 1bbl. Someone should come along shortly to help.

 

thanks anyway.thinking of getting the offenhauser 4bbl intake with the holley 390. what do you know about doing that kind of mod. ive heard good and bad

 

To paraphrase another Okie: All I know is what I read on FTE. And that is that it is a good combo, although the small Edelbrock would be my choice instead of the Holley. Most suggest the EFI exhaust manifolds as well.