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Ford Trucks and vans 1999-2003 (7.3L Powerstroke)

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Heating/Cooling Issues
 
Once the coolant is refilled, it may be necessary to bleed trapped air out of the system to allow proper circulation. The first thing to try is simply driving the car, allowing the cooling system to work the air out on its own. Watch the engine temperature gauge for overheat. Your cooling system is self-bleeding, but if this function doesn’t seem to be working, you can try bleeding the air out at the highest point in the coolant system by loosening a hose or fitting to allow air to vent until only coolant is escaping. DO THIS ONLY WHEN THE ENGINE IS COLD. Be sure the cabin heater temp is set all the way up to allow full coolant flow (IMPORTANT!! Hot coolant can be under great pressure and cause severe burns if that pressure is relieved too quickly). Whenever possible, refer to a workshop manual specific to your make and model. In most cases, this problem is simply a case of trapped air, so driving the vehicle or revving the engine is often all it takes to cough it out
 
Vegetable oil tank or filter not getting hot or taking too long to heat
 
·        The most likely cause of this problem is simply air being trapped in the coolant system, and generally all it takes is a ten-minute drive around the neighborhood to get the coolant flowing. When doing so, however, keep an eye on your vehicle’s engine temperature to make sure the vehicle does not overheat.
·        It’s possible that the coolant hoses were spliced into the stock system incorrectly. Make sure the system is plumbed so that the hottest coolant, fresh from the engine, goes to the filter heater and then back to the tank along the heated fuel line.
·        Check the coolant hoses to make sure they aren’t kinked or pinched anywhere in the system; this will restrict coolant flow and can cause engine overheat.
·        Check all coolant hoses and connections for leaks.
·        Make sure your coolant reservoir cap is tightly closed.
·        It’s possible that your thermostat isn’t closing, allowing coolant to circulate through the radiator before the engine warms up. If this is the case, replace your thermostat.
 
Engine overheating
·        Check that your vehicle isn’t leaking coolant and that your radiator cap is closed tightly. If the radiator cap is open or not functioning properly, the coolant won’t circulate and won’t cool the engine.
·        Check that your coolant is filled up all the way with the correct coolant, mixed with water at the correct ratio.
·        It’s possible that your thermostat isn’t opening, preventing coolant to flow through the radiator. If this is the case, replace your thermostat.
 
 Fuel System Issues
 
General overview of the ’99-’03 Ford Powerstroke fuel system: In the stock fuel system configuration, the electric lift pump draws fuel from the diesel tank through a screen on the fuel level sending unit. It then pushes fuel through the diesel filter into the fuel rails in each cylinder head. The fuel pressure regulator mounted on the diesel filter restricts the flow of the return fuel, thereby regulating the pressure in the filter housing and fuel rails to about 50 PSI. The excess pressure is released through the regulator and that return fuel goes back to the fuel tank.
In the Greasecar configuration, the lift pump is relocated to the engine bay. This pump draws each fuel from its tank and through its filter and then through Valve A. It then pushes the fuel into the Greasecar fuel manifold. The fuel pressure regulator is relocated from the diesel filter housing to the Greasecar fuel manifold, where it restricts the return fuel to maintain pressure in the fuel rails.
To Test for Proper Valve Switching: To see if your valves are switching when they’re supposed to, put the switch in the center position and have an assistant place a hand on each of the valves. When you push the large red square on the switch (purge), the red square should light up and your assistant should feel Valve B switch. Return the switch to the center position. When you push the narrow red line (vegetable oil), the line should light up and your assistant should feel both valves switch simultaneously. With the narrow light on, shut off the ignition. You should hear the Buzz-Box. Switch back to the center position, and the Buzz-Box should turn off.
A note about air leaks in ’99-’03 Ford Powerstrokes: Air leaks in these vehicles can cause all sorts of problems, from hard starting to lift pump cavitation and failure. When you make the connections to the stock steel fuel lines, be sure that the rubber seals are not dried out, cracked or missing. Also make sure these steel lines aren’t rusted and leaking, a situation which can be exacerbated by their manipulation when installing the Greasecar system. The lift pump and diesel filter are now the highest parts of the fuel system, so be certain that all connections to them are airtight. This includes the brass fittings, the connections to the steel lines, the water drain, the electrical connection, the block-off plate that replaces the pressure regulator, and the o-ring underneath the plastic cap. It is very important that all air leaks be eliminated. Since the lift pump is no longer gravity-fed, an air leak can make it lose its prime and run dry at startup, which will damage the pump. If this occurs regularly, the lift pump will fail.
Lift pump failure
·        Check for an air leak. If your diesel filter was empty when the pump failed, you have an air leak, and this is what caused your pump to fail. Even if your filter housing wasn’t empty, you should still check for an air leak and make absolutely sure that the pump is not losing prime. Also make sure that there is no vacuum buildup in your vegetable oil tank. If there is, remove the small, round metal piece on the top of the cap and clean the three small holes underneath. These holes allow air into the tank and can become clogged with oil. Drilling them out a couple sizes should eliminate this problem altogether.
 
Losing prime
·       Many people solve this problem temporarily with a check valve, but since the root cause is an air leak this must properly be resolved. Check all your seals in the fuel system, and see the section on locating an air leak. Also see the note above regarding air leaks in the Ford Powerstroke fuel system.
 
Power loss or rough idle
·        Air may be getting sucked into the fuel lines at a loose connection or through cracks in the fuel lines. To check whether you have an air leak, see the section on <link>locating an air leak</link>.You can often fix this problem by tightening clamps and replacing cracked or damaged lines. Check the o-ring in the pressure regulator and all of the rubber seals on the connections to the steel fuel lines. If there is a loose connection, air can be drawn in and cause the vehicle to run roughly. See the section on locating an air leak below.
 
·        If you’ve run out of fuel on vegetable oil, air has been sucked into the vegetable oil system. You may be able to simply run a purge cycle to remove the air from the lines, but you also may need to refill the fuel filter with fuel. This is the same process as replacing the filter. Also, don’t forget to fill the new fuel filter with fuel whenever you replace the cartridge.
 
·        A fuel line may be kinked. If a fuel line is installed making a sharp-radius bend, it may be restricting fuel flow. If you notice power loss after 10 or 20 miles on vegetable oil, this may be your problem, as fuel lines making sharp bends can lose their rigidity and collapse as they heat up and grow soft.
 
·         The vegetable oil filter may be clogged. This is the number one cause of power loss on vegetable oil. Lift the filter assembly from the heat exchanger and unscrew the filter. The fuel lines should be long enough to enable removing the assembly without disconnecting the fuel lines. Using new vegetable oil from a sealed container, fill the filter canister to the top. Then lightly coat the gasket on the filter with oil and thread it onto the filter head. Once the canister makes contact with the filter head, you need only tighten it another two thirds of a turn. Over-tightening makes it very difficult to remove later and will not improve the seal.
 
·         There may be water in your fuel. Open the drain on the bottom of the vegetable oil filter and drain a cup or so into a clear container. Let it sit in a warm environment for a few hours. If it contains water, layers will form. Alternatively, you can heat up a frying pan and pour the container into it. If it spits and steams, there’s water in your fuel, and you’ll want to reexamine your source or your filtration or storage methods.
 
Coolant in your vegetable oil filter or tank
·        If you’ve found coolant in your vegetable oil filter or tank, do not operate the vehicle on vegetable oil. The most likely place for a leak is the compression nut around the PEX in the fuel tank. Oftentimes the o-ring has been lost or neglected, or the nut wasn’t fully tightened down. Check that the o-ring is correctly seated and the compression nut feels tight and correctly threaded. If this is the case, check the flare nuts on the copper tube for tightness. If they feel tight but you still suspect that they’re leaking, top off the coolant, run the vehicle on diesel, and check for leaks.
 
Not burning vegetable oil
·        Check that Valve A is switching when the switch is in the vegetable oil position (narrow light). If not, see Electrical Issues below. Also check that Valve B switches simultaneously, and that it switches on in purge mode as well.
·        If Valve A is switching properly and you’re still not burning vegetable oil, it is most likely a fuel plumbing issue. Double-check your fuel plumbing against the diagram in the manual.
 
Not purging
·        Check that Valve B is switching when the switch is in the purge position (large light). If not, see Electrical Issues below.
·        If Valve B is switching properly and the vehicle is still not properly purging, it is most likely a fuel plumbing issue. Double-check your fuel plumbing against the diagram in the manual.
·        If Valve B is switching and the system is plumbed properly, but the vehicle still doesn’t seem to be fully flushing the system, change your diesel filter. A clogged diesel filter can reduce the amount of return fuel from the injection pump and/or injectors, as the engine is burning nearly all the fuel it is receiving.
 
Vegetable oil is getting into the diesel tank
·        Make sure that Valve B is switching when you switch to purge and vegetable oil modes. If not, see Electrical Issues below.
·        If Valve B is switching properly, this is a plumbing issue.
·        Double-check your fuel plumbing against the diagram in the manual. It is imperative that they match exactly. You may also want to use the chart on page 13.
·        Double check your wiring. If the wiring matches the diagram, use a test lamp or voltmeter to check your grounds, splicers, butt connectors, and other connections at the valves, switch and fuses. Faulty wiring can cause countless problems.
 
Valve isn’t switching properly
·        Check that the ground is good.
·        Check that the valve is getting power when it’s supposed to. If not, apply power to the valve from a fused lead or a 9-volt battery to make sure the valve is switching properly. If not, double-check the ground.
 
Vacuum buildup in the vegetable oil tank
·        If you notice vacuum buildup when you remove the fuel filler cap on your vegetable oil tank, remove the small round metal piece from the top of the filler cap and clean or drill out the small holes beneath it. These holes can become clogged with oil, and drilling them a couple sizes larger will eliminate this problem.
 
 
Electrical Problems
 
Note: A voltmeter or a test lamp is a very useful tool in diagnosing electrical problems, and nearly all of the troubleshooting steps below require the use of one of these tools.
 
Checking for power: Apply the negative terminal of your voltmeter or test lamp to a known good ground and apply the positive terminal to the 12-volt power supply wire in question. Your test lamp should light up or your voltmeter should read 12 volts.
 
Checking the ground: Apply the positive terminal of your voltmeter or test lamp to a known good 12-volt power source and apply the negative terminal to the ground in question. Your test lamp should light up or your voltmeter should read 12 volts.
 
Valve Issues
 
Valve isn’t switching properly
·        Check that the ground is good.
·        Check that the valve is getting power when it’s supposed to. If not, apply power to the valve from a fused lead or a 9-volt battery to make sure the valve is switching properly. If it is not, double-check the ground.
 
Switch Issues
 
Switch isn’t lighting up
·        Make sure the connection to terminal 2 is getting power. This will be switched power without a Buzz-Box and constant power with a Buzz-Box.
·        Check the ground at terminal 7.
Switch not working properly
·        Check that the valves are getting power when they’re supposed to. If not, check all the connections between the valves and the switch.
·        Check the grounds on the valves.
·        Check the ground on the switch.
·        Check that terminals 5 and 2 on the switch are getting power.
·        If 5 and 2 are getting power and the ground on the switch is good, check that terminals 3 and 6 are getting power on vegetable oil mode and that only terminal 4 is getting power on purge. (Terminal 1, the open terminal, should also get power on purge.)
 
Fuel Level Gauge and Sender Issues
 
Gauge lights up but always reads empty
·        Make sure that the sender wire is properly connected.
·        Make sure that the fuel level sender is properly grounded.
·        Check the proper function of the gauge by disconnecting the sender wire from the fuel level sender and connecting it to ground. The gauge should jump up to full.
 
Gauge lights up but always reads full
·        This means your sender wire is grounding out somewhere. Check for damaged insulation along the length of the wire.
 
Gauge doesn’t light up
·        Make sure that the the blade terminal on the back of the switch is getting power. This terminal provides power to the light.
·        Make sure the center post is grounded properly.
 
Buzz-Box Issues
 
Buzz-Box doesn’t buzz
·        Check that it’s getting constant power from the red wire when the switch is in the vegetable oil position.
·        Check that the ground is good.
 
Buzz-Box always buzzing or buzzing at the wrong time
·        Check that the blue wire is getting power when the ignition is on and no power when the ignition is off.
·        Make sure the red wire is spliced into the power lead to Valve A.
 
 
Finding an air leak:
 
To Check for A Leakage: Insert a length of clear hose into the fuel line between the lift pump outlet and the fuel manifold inlet. Select the fuel on which you are experiencing power loss and rev the engine. If you see no air bubbles in the clear line, your power loss is due to other factors.
 
Air leak on vegetable oil only:
1. Move clear hose between VO filter outlet and NC on Valve A.
            If you see no air, check the hose, clamps and fittings between Valve A and the lift pump, including the fittings on the lift pump.
2. If you still see air bubbles, move the clear hose to the line between the nylon return tee and the vegetable oil filter inlet.
           If you see no air, check the hose, clamps and fittings between the VO filter outlet and Valve A. Also make sure the filter is sealed against the filter head, the drain on the filter is closed, and the fittings in the filter head are tight.
3. If you still see air, move the clear hose to the line between the PEX and the nylon tee.
            If you see no air, check the hose, clamps and fittings between the nylon return tee and the vegetable oil filter inlet.
4. If you see air, check the hose and the hose clamp on the PEX. Also make sure the PEX in the tank hasn’t come loose from the copper coil and risen above the level of the oil.
5. If you still see air bubbles entering the fuel manifold, move the clear hose between Valve B and the nylon return tee. If no air, start again at Step One.
6. If you see air, check the fittings, hoses and connections on the fuel manifold and Valve B. Make sure that all parts of Valve B are secure and do not move.
 
Air leak on diesel only:
1. Move clear hose between diesel filter and Valve A.
            If no air, check hose, hose clamps, and NO and COM fittings on Valve A.
2. If you see air, check all fittings and seals on diesel filter, including the o-ring under cap and the water drain. Also check steel lines for rust and the rubber seals at the connections of these lines to the diesel filter.
 
Air leak on both fuels:
1. Move clear line to the line between Valve A and the lift pump inlet.
            If no air, check connections to lift pump inlet.
2. If you see air, check Valve A fittings for tightness.
            If air remains in the lines:
3. Consider the possibility of multiple air leaks. Use the procedures above for locating an air leak on each fuel.