Hey Scotty and admin,
I have a carburated 1986 f150 2wd i6 300cu. When starting it cold in the morning, i pump the pedal three-four times before cranking it, and as i watch my aftermarket mechanical oil gauge, the truck only starts when oil pressure just starts to build up. Once the truck is warm it starts with one crank. Is there a safety switch that i can remove or is this stock on the truck, and the only way of removing it is to change distributors?
I don't want to wear out my starter by cranking the truck for a long time, because it has headers and the starter moter is in the middle of all the pipes.
Thanks ^^
George
That more or less sounds like what happens with my Pontiac that's a few years older. There is no safety switch for oil pressure and starting the car. Even modern vehicles with fuel injection and computers don't have that kind of thing, to my knowledge. They will just turn on the idiot light for oil pressure if your pressure is low, the engine will still run, but not very long. Oil starvation destroys engines quickly.
It takes a second for the pump to pressurize the system. Old carbureted engines were built to tolerate that. It's also because carburetors aren't exactly "idiot proof", the fuel is put in by you pumping the pedal, sometimes you nail the mixture and it starts right away from cold, other times you are too rich, or too lean, because you pumped the gas too much or too little. Once the engine is hot on a carbureted motor, enough gas has evaporated from the fuel bowl that as soon as the engine moves from the starter cranking, it will fire on the next power stroke if the carb is set right.
The starter on these old beasts are made to crank their motors over for several seconds, modern starters wear out if you excessively crank them because engineers have made the starters weaker, a computer is running everything. You can't flood out a fuel injected engine as easily as you can a carburetor when you're trying to start it, and the engineers knew this. Standard procedure is hold the pedal down and crank for several seconds to clear it, and the engineers designed them to do this. Don't worry about it 🙂 /p>
You should have some type of automatic choke system on that old girl and it sounds like it's not working correctly. Usually, you just push the pedal to the floor which sets the choke and turn the key. It should start right up. Check your carb choke system, the linkage and any parts like the fast idle settings, etc. for proper function. When did you last re-built the carb? Carb rebuild kits these days have the new viton seals that aren't affected by the alcohol in the gas that eats up the rubber parts of the carb.
Yes, before the winter started I checked all the linkages. The choke operates correctly, the throttle is fine, i re-built the carburator just before i did all that with a carb kit from carburation.com, and i ONLY use non ethanol gas in it. When it starts, it sounds amazing.
I tested this on three different days with same temperature. One with three pumps, one with four pumps, and one with 7 pumps to the pedal. All act the same way until oil pressure just begins to rise then the truck starts. It's really weird.
When i first bought the truck there was a bolt that kept the choke locked out. I changed that and verified that nothing gets in the way. When it finally starts the engine revs slightly higher due to the choke so i can guarentee it works.
Hopefully the conversion to a points distributer instead of the TFI Distributer will make this problem "go away"
The cold start issue has nothing to do with oil pressure, that is just coincidental. As others have mentioned you may need your choke adjusted or have some other carb or ignition issue which is causing hard starting when cold.
There have been vehicles where oil pressure was used to trigger an electric fuel pump and when that switch went bad the engine would die while driving, or just wouldn't start in the first place. The Chevy Vega was like that. Back in the day the vast majority of cars still had carbs and ignition points and most had mechanical fuel pumps. Owners and even most mechanics were not familiar with electric fuel pumps or, in the case of the Vega, the oil pressure switch controlling the pump.
You used to be able to pick a Vega up for next to nothing from exasperated owners who couldn't figure out why they wouldn't run. Then you could just put in a new oil pressure switch for a few bucks and run down the road until the stupid Vega engine gave up the ghost which would usually happen in short order.
I'm guessing it's the cold weather, cuz i tried this three different times at three different days, with different pumps to the pedal, and they do all the same thing. I sure hope it's coincidence.
As replied to before, i checked all the carb linkages, choke, throttle, cleaned the carb and set the ignition timing to 10btdc according to the Haynes Shop manual.
This truck has a mechanical fuel pump so it's def. not that.
Along with temperature, another thing that will affect how many pumps you need to initially start the engine is how long it's sat since you drove it last. If I drive my Catalina several days in a row, usually 2-3 pumps will start it after sitting overnight. If it sits for any length of time, it'll take 4-6 pumps to get started. I got my carburetor to start in 7 degree F weather a few weeks ago, it took 6-7 pumps, but it caught, no problem. There's a bit of a learning curve to operating them, especially if you're going backwards from fuel injection, but if everything is truly set correctly, you'll get the feel for it with practice and repetition.
You might want to check that you have the correct float level and also that the carb accelerator pump diaphragm is working correctly.
I'm assuming the coil isn't on the distributor like a gm hei & is remote, if so run a toggle switch to the wire that powers the coil.
Keep it in the off position until you get pressure. Just limit your cranking to four seconds or less, you won't burn it out. The header is irrelevant if it's not up to temp, that takes a few minutes.
If you're dead set on having a header instead of manifold, find a short tube design that way you can route the exhaust pipe away from the starter. With long tube headers you'll always have heat soak issues.
One other thing you can do is buy some header heat wrap & cover the section by the starter with a few turns of it. They sell it at most parts stores, it's white & woven.
