When starting in the cold the instructions say to put the throttle at half. When I start my B3300SU up it sounds very rough, Knocking and smoking. It stops in about 15 seconds. Im thinking its going to get worst when it even gets colder. Is this normal ?
rough start, Is this normal ?
- Thread starter bbbobbb
- Start date
I have always interpreted 1/2 throttle to mean 1/2 of rated (max) rpm, about 1300 rpm for me, not half way between idle and max, which would be closer to 1800 rpm.
So, I do bump the throttle up for cold and warm starts. I idle at "50%" (13-1400 rpm) when it is really cold for engine/fluid to warm some.
I use the glow plugs as directed and run 15W40 oil. I will get a small puff of smoke and maybe a second of rough or noisy running before 'normal'. Maybe a little different than warm weather, but not much.
What cetane is your diesel? My manual recommends 50 cetane and what I run is 50-51 (Premium diesel from CountryMark). Cetane number will certainly affect smoothness of cold starts. Truck stop diesel averages about 44 on the cetane unless you run a cetane booster.
Wxman
So, I do bump the throttle up for cold and warm starts. I idle at "50%" (13-1400 rpm) when it is really cold for engine/fluid to warm some.
I use the glow plugs as directed and run 15W40 oil. I will get a small puff of smoke and maybe a second of rough or noisy running before 'normal'. Maybe a little different than warm weather, but not much.
What cetane is your diesel? My manual recommends 50 cetane and what I run is 50-51 (Premium diesel from CountryMark). Cetane number will certainly affect smoothness of cold starts. Truck stop diesel averages about 44 on the cetane unless you run a cetane booster.
Wxman
Yeah you really don't want to start it with a bunch of throttle before the big end bearings get a chance to get oil pressure. Just off idle is where you want to be. The exception would be some sort of cold starting system connected to the throttle lever (ever used a thermostart?).
A second or two of roughness is pretty good for a diesel. You're feeling several different things. First the chamber takes time to get hot enough that the incoming air charge isn't too cold to allow complete combustion. The glow plugs take up a lot of the slack but it still takes time for the combustion to warm the walls up the rest of the way. I worked with a Ford 4500 3 cylinder that actually doesn't have glow plugs. It's got this funny thing called a thermostart (video) that actually injects fuel onto a heat coil in the intake manifold and burns it to warm the incoming charge. I believe it's a direct injection engine but if you managed to get the thing started in cold weather it would sit there and vibrate and pour smoke for a good 5 minutes til the chamber came up to temperature. Thick cold oil is also being pumped out and you get a little bearing clack until it's worked it way out to the bearings on the end of the system. Finally all of the cold metal has shrunk and the fitment is a little loose till all of the fluids and metals in the engine come up to operating temperature and that can cause a little roughness.
A second or two of roughness is pretty good for a diesel. You're feeling several different things. First the chamber takes time to get hot enough that the incoming air charge isn't too cold to allow complete combustion. The glow plugs take up a lot of the slack but it still takes time for the combustion to warm the walls up the rest of the way. I worked with a Ford 4500 3 cylinder that actually doesn't have glow plugs. It's got this funny thing called a thermostart (video) that actually injects fuel onto a heat coil in the intake manifold and burns it to warm the incoming charge. I believe it's a direct injection engine but if you managed to get the thing started in cold weather it would sit there and vibrate and pour smoke for a good 5 minutes til the chamber came up to temperature. Thick cold oil is also being pumped out and you get a little bearing clack until it's worked it way out to the bearings on the end of the system. Finally all of the cold metal has shrunk and the fitment is a little loose till all of the fluids and metals in the engine come up to operating temperature and that can cause a little roughness.