99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
Having a bit of a starting issue. Hard start and white smoke. Kind of hard to get a handle on as temps have been up and down, just trying to get some ideas of things to look at. I have new batteries and a new gpr. How many amps will will the glow plugs pull when cycled on? Do they pull more the colder the temp is? I searched the form but all I found were ohm readings for the glow plugs themselves.
2000 f3504x4, cc, lwb, 7.3, K+N air filter, ATS three stage chip, 4" ss turbo back exhaust, dual outlet ss muffler, 5" polished tips, American 143 16.5x9.75 wheels, Goodyear GSA 37-12.50s, Fabtec 5.5" lift, 2002 headlights and markers, stereo and video !
Spec for GPs are .3 to .5 ohms. Since there are 8 in parallel, that's .037 to .0625 ohms. Using this range of resistance and ohms law to solve for current (i=e/r) assuming 12 volts, that's 12V/.037Ohms=324 Amps to 12V/.0625Ohms=192 Amps. To calculate the power in watts use (p=i*e), or 3888W to 2304W. In theory, the hotter the GP gets the higher its resistance becomes (less current draw). The difference in initial current draw between a 70F and -20F GP is minor when you consider an energized GP reaches about 2000F. Normally when GPs fail their resistance increases, so anything above .5 ohms is considered bad.
2011 F450 King Ranch, Royal Metallic Red, BW Turnover Hitch, Torklift Camper Tie Downs, Air Lift LoadLifter5000 Bags w/ WirelessAIR
Early 99 XLT F350 4X4 SuperCab Long Bed SRW
Mods: AIS Intake, BTS tranny, DP Tunner, Isspro A Pillar Trans Temp, Boost, Pre Turbo EGT, 19.5" Vision Heavy Hauler Wheels, Michelin XDS2 Tires, GTP38R Turbo, Non EBPV Turbo Pedestal, DI Intercooler, DI Uppies, DI HP Oil Cross-over, DI Regulated Fuel Return, BW Turnover Hitch, Rear Hellwig Stabilizer Bar, Rear Timbren Suspension, Moog Ball Joints, 2009 Al Rear Diff Cover, Banks 4" Monster Exhaust with Power Elbow, Torklift Camper Tie Downs, Tekonsha P3 Brake Controller
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