so it got really cold last night, as in the negatives -10 last time i had checked after the superbowl. this morning i got in the truck and fired it up, was expecting it to crank slower, and it did, but when it fired i counted to three and had no oil pressure so i shut if off fearing engine damage as it hadnt been driven all weekend. then to get oil pressure i pressed the gas pedal all the way down so that it wouldnt fire while i cranked it for 5 seconds until the oil pressure idiot gauge moved, i then let off the starter and gas pedal and it fired right off with oil pressure and all. my question is does this hurt anything to press the gas pedal down to keep it from firing while building oil pressure when it is really cold? i know it wastes a little fuel but other than that are there any negatives?

 

Flooring the throttle during start mode shuts off the fuel injectors. It's used to clear a "gas flooded" engine.

I use the same technique when starting a vehicle that has sat for awhile or the first start after a filter/oil change.

 

Yep, what Randy said. Applying full throttle before you start cranking will cause the computer to not inject any fuel at all. I do this after oil changes as well.

Great prank (if you're the one driving) next time you're out with your wife/girlfriend/buddies and wanna get somewhere on time...

 

This is a great tidbit of info!!

 

And to expand, with carbed engines (that tended to flood pretty easily) opening the throttle all the way was how you cleared a flood, because it let more air in. When they went with EFI automotive engineers were smart enough to use the same tool (letting lots of air in to clear a flood) but went one better by shutting off the fuel as well.

If the engine is flooded and you crank it while holding the pedal on the floor it will start once it's cleared enough gas to not be too rich to run. But if you've got no gas in there to begin with, holding the pedal on the floor while cranking will keep it that way, no gas, and it won't start.

It doesn't waste gas (see above) and it's probably quite a bit better for the engine to crank until you get oil pressure than running it because there's a LOT less pressure on the bearings when all they have to do is make the pistons go up and down. With the engine running all of the force from the power stroke is going through the (dry) bearings. They like it a whole lot better to have oil when they need to support a load like that.

Obviously it has the negative of running the battery down. No biggie if it's still cranking relatively strong and the engine starts. And turning a cold engine is going to result in more wear than turning a warm one. But short of parking in a heated garage (which is hard on the sheet metal), we're stuck with cold starts. And as noted, your method is probably better than just starting it right up.

 

sweet, did not know it killed the injectors, yeah it would be nice to have it in a heated garage but the shed its in now is better than outside even without juice to it, ideally i would plug it in overnight but the only way that would work is a generator in the back lol

 

Well I just tried it. Oil temp is 25 so I thought I'd get the oil pressure gauge firmed up before firing it up.

May be operator error. I put the foot feed to the floor then turned the key from full off to all the way to crank and it fired and revved right on up.

 

I have owned 7 fuel injected gas Fords and countless Chrysler/Dodge products they all have the same fuel injector shut off feature at cranking with WOT applied.

Make sure the floor mat is not blocking the throttle from going wide open. It may be beneficial to verify the throttle blades are going full open too. Perhaps the throttle cable is stretched or your TPS output is low.

I see you have a diesel.......No idea if they have the same feature as the gas engine cars/trucks.

 

rla2005, yes, and I just now reversed my cranial rectum inclusion and see y'all have gassers.

 

We maybe should have been more clear about that.

And even gassers will start like that if they already have gas in the intake manifold. All it does is not open the injectors while the pedal is flat on the floor and the key is in the "crank" position. If it pops over and you let go of the key it'll start giving it gas and will likely start. It's the popping over the first time that's somewhat unlikely, especially if the engine is cold and you put it flat to the floor before you start cranking at all.

By the way, once when I was in college I stopped to help someone who couldn't get their car started. I smelled a LOT of gas so I told him to hold the pedal flat on the floor. He said that's what he'd been doing and asked me to watch the engine while he tried again. I'm thinking no chance I'll see anything wrong, but it turned out I did. I could see his throttle slamming from WOT to closed and back about twice a second. Some people's definition of "flat on the floor" apparently is different from mine. Pumping the pedal will even flood an EFI engine. So I grabbed the throttle at the TB and held it open until the engine started while the cable kept twitching. He thanked me and I left.