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Ford V-10 6.8L Engine

The Ford V-10 6.8L is a 6.8 L 10-cylinder engine rated at 1800 rpm. It powers generator sets from Cummins/Onan, including the GGHG and GGHH. It holds 5.5 L (1.5 gal) of oil.

Also known as: Ford V-10 6.8L

6.8 L

Displacement

Cylinders

1800 rpm

Rated speed

5.5 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Fault codes Procedures Wiring

Engine specifications

Oil capacity	5.5 L
Displacement	6.8 L
Cylinders	10
Rated speed	1800 rpm

Generator sets powered by this engine

Cummins/Onan GGHG Cummins/Onan GGHH

Troubleshooting

Fault codes

Code	Meaning
E3	Evaporative Emissions System Leak

Fault codes and symptom→remedy steps extracted from this engine’s service/owner documentation; verify against the official manual before servicing.

Common problems

The engine does not crank in Run mode
Cause: The Emergency Stop switch has been used. (The switch button is lit.)
Fix: Pull the Emergency Switch button. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Run to start the genset.
The engine cranks but does not start
Cause: The engine is not getting fuel.
Fix: Open any closed fuel shutoff valve. (Valves closed for maintenance or new installations may require several crank cycles to get fuel to genset); Fill the propane supply tank; For natural gas fueled sets, check with the gas utility; Check fuel pressure at regulator (refer to Fuel Pressure in Section 6.) (High fuel pressure will prevent solenoid from opening); Check fuel solenoid (VDC present at K1+ lead during cranking); Duel Fuel Sets Only: Check relay K99. Refer to wiring diagrams in Section 7; Check pressure switch wiring. Propane − normally closed connected to common. Natural gas − normally open connected to common; Check pressure switch function (@ 3.5 inch H2O or less, should switch from natural gas to LPG); Check S14 vacuum switch (optional) for proper operation.
No output voltage
Cause: The line circuit breaker is OFF.
Fix: Find out why the circuit breaker was turned OFF, make sure it is safe to reconnect power, and then throw the circuit breaker ON.
The engine lacks power or is unstable
Cause: Current ambient conditions cause a derate, limiting power to less than rated power.
Fix: Determine proper derates for ambient conditions. Refer to specification sheet for site derating factors.
The field circuit breaker keeps tripping
Cause: The rotating rectifier assembly (diodes CR1 through CR6) is faulty
Fix: Shut down the set and check each diode according to Section 7; Service as necessary
The engine does not crank in Remote mode
Cause: The Run-Stop-Remote switch is at Stop. (The Switch-Off light will be flashing.)
Fix: Push the Run-Stop-Remote switch to Remote.
Battery completely discharged
Cause: Poor battery terminal connection
Fix: Clean connections, replace and tighten.
Output voltage is too high or too low
Cause: Engine speed is unstable
Fix: Troubleshoot according to the chart, The Engine Lacks Power or is Unstable
Engine will not crank.
Cause: Fault lamp on
Fix: Correct fault and reset control.
Battery low charge
Cause: Poor battery connection
Fix: Clean connections, reconnect and tighten securely.
The phase currents are unbalanced
Cause: The connected loads are distributed unevenly among the phases
Fix: Shut down the set and redistribute the loads as evenly as possible
The FAULT 1 or FAULT 2 fault lamp lights. Engine shuts down immediately, engine runs for several seconds and then shuts down, or engine continues to run. FAULT 1
Cause: The standard undesignated fault functions are programmed to shut down the set when a fault is sensed. Fault 1 is time delayed while Fault 2 is immediate. The nature of the fault is an optional selection that is determined when the set installation is designed. The undesignated fault functions may also be programmed for non-shutdown or non-time delay.
Over Current 1477
Output voltage is unstable
Cause: The voltage has been adjusted improperly
Fix: Adjust output voltage according to Section 2, AC Control
Battery overcharged
Cause: Charge alternator fault
Fix: Contact your nearest Cummins Power Generation distributor.

Compiled from service & troubleshooting documentation across every generator set that uses the Ford V-10 6.8L.

Maintenance schedule

Item	Spec	Capacity	Part #	Interval
Air filter	Paper-type element - do not clean, replace		—	500 hr
Fuel filter			—
Oil filter			—	50 hr
Battery	Dilute sulphuric acid (electrolyte) of correct specific gravity per battery label		416-0823		Amazon
Belt			—
Coolant	50% Ethylene Glycol and water	33.1 L	—
Oil	High-quality multi-viscosity lubricating oil, e.g. Cummins Premium Blue® or equivalent	6.2 L	—
Spark plug			—	1000 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Air cleaner (normal duty filter)	Check	100 hr		Perform more often in extremely dusty conditions; replace element after 500 hours.
All exhaust components and hardware (fittings, clamps, fasteners)	Check	8 hr		Daily; audibly and visually with generator set running
All hardware (fittings, clamps, fasteners, etc.)	Check	100 hr		Daily or after 8 hours.
Bedframe fluid containment (where fitted)	Drain	8 hr		Daily; drain if necessary
Coolant heater(s)	Check	8 hr		Daily.
Coolant level	Check	8 hr		Daily.
Coolant level of radiator(s) (water jacket & LTA)	Check	8 hr		Daily
Cooling fan blades	Check	8 hr		Visual inspection required daily
Drive belt condition and tension	Check	8 hr		Visually check belt for wear or slippage; replace if hard or brittle (Service Engineer)
Engine oil level	Check	8 hr		Daily.
Fuel level in tank	Check	8 hr		Daily or after 8 hours
Fuel lines and hoses	Check	8 hr		Daily; check for oil, fuel, coolant and exhaust system leaks (Table 5 note 1)
General set	Inspect	8 hr		Check for oil, fuel, cooling and exhaust system leaks; inspect exhaust audibly/visually with set running and repair leaks immediately.
General set inspection	Inspect	8 hr		Daily. Check for oil, fuel, cooling and exhaust system leaks; check exhaust audibly and visually with set running.
Crankcase oil	Change	50 hr		First service — Drain and replace crankcase oil after the first 50 hours of operation on new generator sets (break-in).
Engine oil and filter	Change	250 hr	6 mo	First service — Replace after the initial running-in period of 50 hours; contact your authorized distributor (Table 5 note 5)
Engine oil and filter	Drain	50 hr		First service — Break-in: drain and replace crankcase oil after first 50 hours of operation on new generator sets.
Air cleaner	Check	100 hr		Monthly; replace as necessary. Perform more often in extremely dusty conditions.
Battery electrolyte level	Check	100 hr	1 mo	Monthly.
Engine oil and filter (normal duty filter)	Change	100 hr	12 mo	Perform more often in extremely dusty conditions; perform at least once a year.
Generator air outlet	Check	100 hr	1 mo	Monthly.
Governor linkage	Check	100 hr		Perform more often in extremely dusty conditions.
All hardware (fittings, clamps, fasteners)	Check	250 hr	6 mo
Drive belt	Check	250 hr	6 mo	Visually check for wear or slippage; replace if hard or brittle.
Engine coolant port caps	Check	250 hr	6 mo	Replace after 4 years or 1000 hours.
Exterior of radiator	Inspect	250 hr	6 mo	Inspect for obstructions.
Radiator exterior	Inspect	250 hr	6 mo	Inspect for obstructions.
Radiator hoses	Check	500 hr	12 mo	Check for wear and cracks; replace if hard or brittle.
Radiator hoses	Inspect	250 hr	6 mo	Replace if hard or brittle.
AC generator and controls	Check	500 hr	12 mo	Yearly.
Anti-freeze	Check	500 hr	12 mo	Yearly.
Anti-freeze concentration	Check	500 hr	12 mo	Yearly or after 500 hours.
Catalytic converter restriction	Test	500 hr	12 mo	Must be performed by a qualified mechanic; replace every 8 years or 2000 hours.
Cooling systems	Clean	500 hr	12 mo	Yearly.
Oxygen sensor	Inspect	500 hr	12 mo	Must be performed by a qualified mechanic; replace every 1,500 hours (recommended).
Radiator	Drain	1000 hr	24 mo	Drain and flush.
Spark plugs	Inspect	500 hr	12 mo	Replace every 1,000 hours.
Cylinder heads	Other	1000 hr	24 mo	Overhaul cylinder heads.
Alternator vibration levels	Check	3000 hr		Table 6 (3000 hours)
Fuel injectors	Check	3000 hr		Table 6 (3000 hours); to be undertaken by a Service Technician

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Service specifications

Type	Item	Value	Unit	Condition
Clearance	Clearance around generator set for service	1	meter
Clearance	Exhaust pipe clearance to combustible wall or partition	305	mm
Clearance	Isolator base elevation tolerance between isolators	0.25	inch (6 mm)
Clearance	Vibration isolator top plate to base clearance	0.25	inch
Clearance	Vibration isolator top plate-to-base clearance (nominal)	0.25	inch (6 mm)
Gap	Spark Plug Gap	0.044	in (1.1 mm)
Gap	Spark plug gap	0.035	in (0.9 mm)
Gap	Spark plug gap	0.044 (1.1 mm)	in (mm)
Other	Adjust - Frequency Adjust range	5	% of nominal frequency
Other	Adjust - Voltage Adjust range	5	% of nominal voltage
Other	Air cleaner bench/paper element cleaning	Not recommended		Cummins Inc. does not recommend cleaning paper-type air cleaner elements
Other	Battery charger output - 12 Volt	15	A
Other	Battery charger output - 24 Volt	12	A
Other	Battery electrolyte specific gravity (fully charged, corrected)	1.260	SG	at 25 °C (77 °F)
Other	Battery specific gravity, charge required below	1.215	specific gravity
Other	Battery specific gravity, fully charged	1.260		corrected; add 0.004 per 10 F above 80 F (27 C)
Other	Battery specific gravity, fully charged (corrected)	1.260	specific gravity	corrected to 80°F (27°C)
Other	Battery specific gravity, recharge threshold	1.215		charge battery if reading is below this value
Other	Battery storage charging - further charge interval	6	months	at the normal initial charge rate until voltage ceases to rise
Other	Boost Charge interval (if charger fitted with Boost switch)	6	months	normally around every six months per battery manufacturer
Other	Charge battery if specific gravity below	1.215	SG
Other	Cooldown at idle timer	0 - 30	minutes
Other	Low Fuel warning (yellow lamp)	5	inches (127 mm) WC or less	dual or single fuel systems
Other	Output voltage adjustment range (voltage adjust rheostat, optional)	±5	% of nominal voltage
Other	Overcrank timed cranking period	approximately 75	seconds, including two rest periods
Other	Rated To Idle delay	0 - 10	seconds	default = 0; Beginning Version 2.303
Other	Secondary regulator initial adjustment (distance from top of regulator to top of set screw), NG, 60 Hz	12.1	mm
Other	Secondary regulator initial adjustment, NG, 60 Hz	13.35	mm
Other	Secondary regulator initial adjustment, NG, 60 Hz	15.9	mm
Other	Specific gravity temperature correction	0.007	SG per 10 °C (18 °F)	subtract above 25 °C (77 °F), add below
Other	Specific gravity, at end of charge, ambient frequently above 32 °C (90 °F)	1.240 - 1.260	SG
Other	Specific gravity, at end of charge, ambient normally below 32 °C (90 °F)	1.240	SG
Other	Specific gravity, electrolyte for filling new cells, ambient frequently above 32 °C (90 °F)	1.270 - 1.290	SG
Other	Specific gravity, electrolyte for filling new cells, ambient normally below 32 °C (90 °F)	1.270	SG
Other	Start Delay	0 - 300	seconds	default = 0
Other	Starting cycles (crank/rest)	3	start cycles	default: 3 cycles composed of 15 seconds of cranking and 15 seconds of rest
Other	Stop Delay	0 - 600	seconds	default = 0
Other	Time Delay To Stop	0 - 600	seconds
Other	Warm-up at idle time delay	0 - 300	seconds
Pressure	Concrete compressive strength for seismic anchors	4000	PSI
Pressure	Exhaust Backpressure (Max. Allowed)	25	inch H2O (6.25 kPa)	maximum
Pressure	Exhaust backpressure (max allowed)	20	inch H2O (5.0 kPa)
Pressure	Fuel inlet pressure (LPG liquid withdrawal)	312	psi (2,153 kPa)
Pressure	Fuel inlet pressure maximum (LPG liquid withdrawal)	312	psi (2,153 kPa)	liquid withdrawal
Pressure	Fuel inlet pressure maximum (NG/LPG vapor withdrawal)	13.6	inch H2O (3.4 kPa)
Pressure	Fuel inlet pressure minimum (NG/LPG)	7.0	inch H2O (1.7 kPa)
Pressure	Gaseous fuel supply inlet pressure - maximum operating	13.6	in. water column (25.4 mmHg)
Pressure	Gaseous fuel supply inlet pressure - minimum operating	7.0	in. water column (13.07 mmHg)
Pressure	LO FUEL lamp (fuel supply pressure marginally low)	5 (127 mm) WC or less	inches WC
Pressure	LOP jumper alternate shutdown setting	14	psi (97 kPa)	alternate jumper position (not recommended, see caution)
Pressure	LP gas pressure at full load	negative 1.0	inch WC (0.249 kPa)	full load
Pressure	LP gas pressure at mixer, full load	-1.0	inch WC (0.249 kPa)	full load
Pressure	LP gas pressure at mixer, no load	-0.5	inches WC (0.13 kPa)	no load
Pressure	LP gas pressure at no load	negative 0.5	inches WC (0.13 kPa)	no load
Pressure	LPG Liquid Withdrawal Fuel Flow Inlet Pressure Maximum	312	psi (2,153 kPa)	maximum
Pressure	LPG gas pressure at mixer, full load	approximately -1.0	inches WC
Pressure	LPG gas pressure at mixer, no load	approximately -0.5	inches WC
Pressure	Low Oil Pressure shutdown (red lamp), LOP jumper set to 25 psi	less than 25	psi (173 kPa)
Pressure	Low fuel pressure alarm (engine control module)	3 (76.2 mm) water column	inches WC	primary fuel pressure falls below
Pressure	Low oil pressure shutdown	25	psi (172.4 kPa)	~10 second time delay after starter disconnect

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Recommended fluids

Fluid	Grade	Standard	Ambient	Capacity	Notes
Coolant	50% Ethylene Glycol and water	Fleetguard® Compleat ES low-silicate antifreeze, or equivalent			Standard concentration 50% Ethylene Glycol and water; must be maintained. Fill cooling system to the bottom of the fill neck in the radiator or expansion tank. Some radiators have two fill necks, both must be filled.
Coolant	50/50 coolant solution (50% pure water, 50% antifreeze); 65% antifreeze/35% water if below -37°F (-38°C)			33.1 L	Cooling system capacity with standard radiator 8.8 Gal (33.1 L). Use clean, low-mineral soft water free of chloride, sulfate or acid. Do not use antifreeze containing anti-leak additives.
Coolant	50/50 water/antifreeze (65% antifreeze/35% water below -37F/-38C); no anti-leak additives		above -38°C	8.8 Gal (33.1 L)	Use soft water low in mineral content.
Coolant	50/50 coolant solution (50% pure water and 50% antifreeze)	Do not use antifreeze containing anti-leak additives; use soft, low-mineral water	above -37°C	33.1 L	If temperatures below -37 F (-38 C) are possible use 65% antifreeze and 35% water. Cooling system capacity with standard radiator 8.8 Gal (33.1 L).
Engine oil	High-quality multi-viscosity lubricating oil such as Cummins Premium Blue® or its equivalent				Consult your authorized distributor for correct lubricating oil specifications for your operating conditions. Special running-in oils are not recommended.
Engine oil	Refer to oil viscosity chart (Figure 5-1)	API SJ or SJ/CD		6.2 L	Select grade right for the lowest ambient temperature expected.
Engine oil	SAE 10W30, 5W30, 15W40	API classification SJ, SH or SL		6.2 L	Oil capacity with filters 6.5 Qts (6.2 L). Select viscosity grade for lowest expected temperature; if ambient is consistently below -13°F (-25°C), use a SAE 5W synthetic oil. Do not use oil that is too thick.
Engine oil	API SJ, SH or SL; SAE 10W30, 5W30 or 15W40 per ambient temperature chart	API	above -25°C	6.5 Qts (6.2 L)	Use SAE5W synthetic oil if ambient temperature is consistently below -13F (-25C).
Engine oil	SAE 5W synthetic	API SJ or SJ/CD	above -25°C	6.2 L	Use SAE 5W synthetic if ambient temperature is consistently below -13 F (-25 C). Pick viscosity grade for lowest temperature expected. Oil capacity with filters 6.5 Qts (6.2 L).
Fuel	Natural Gas and/or Propane (LPG, liquid or vapor withdrawal)				Combination natural gas/LPG sets have separate shutoff solenoid valves and a fuel pressure switch for automatic changeover.
Fuel	Natural Gas and/or Propane (LPG, liquid or vapor)				Gaseous fuel; engine has a gas mixer serving both fuels with separate shutoff solenoid valves and pressure switch for automatic changeover.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Fault codes

Code	Name	Meaning	Severity	Action
121	Speed Signal Lost	Category A	Shutdown
135	Oil Pressure Sensor H	Category C	Warning
141	Oil Pressure Sensor L	Category C	Warning
143	Pre-Low Oil Pres	Category D	Warning	If generator is powering critical loads and cannot be shut down, wait until next shutdown period and then follow code 415 procedure.
144	Coolant Sensor High	Category C	Warning
145	Coolant Sensor Low	Category C	Warning
146	Pre-High Coolant Temp	Category D	Warning	Reduce load if possible by turning off non-critical loads; check air inlets/outlets for obstructions. If engine can be stopped, follow code 151 procedure.
151	High Coolant Temp	Category D	Shutdown	Allow engine to cool. Check coolant level and leakage points, obstructions to cooling airflow, fan belt, blower fan/circulation pumps; reset control and restart.
197	Low Coolant Level	Category D (optional)	Warning	If generator is powering critical loads and cannot be shut down, wait until next shutdown period, then follow code 235 procedure.
234	Overspeed	Category A	Shutdown
235	Low Coolant Level	Category D (optional)	Shutdown	Allow engine to cool. Check coolant level and replenish, look for leakage points and repair; reset control and restart.
359	Fail To Start	Category D	Shutdown	Open any closed fuel shutoff valve; check for dirty/plugged air filter and replace if necessary; check gaseous fuel delivery; reset control and restart.
415	Low Oil Pressure	Category D	Shutdown	Check oil level, lines and filters; replenish oil if low; reset control and restart.
441	Low Bat Voltage	Category D	Warning	Check/recharge/replace discharged or defective battery; clean and tighten battery cable terminals; check battery charger float level.
442	High Bat Voltage	Category D	Warning	Check float level on battery charger if applicable (lower float level).
1123	Shutdown After BS	Category A	Shutdown
1124	Delayed Shutdown	Category E	Warning
1131	Battle Sh Active	Category E	Warning
1311	Customer Input #1	Category E		Programmable via InPower service tool: enable/disable, status (warning/shutdown/none), active open/closed, and display name.
1312	Customer Input #2	Category E		Programmable via InPower service tool: enable/disable, status (warning/shutdown/none), active open/closed, and display name.
1313-1316	Network Fault 1 thru 4	Category E
1317	Customer Input #3	Category E		Programmable via InPower service tool: enable/disable, status (warning/shutdown/none), active open/closed, and display name.
1318	Service Engine	Category B (begin spec J)	Warning	Indicates emissions criteria might not be met: engine running in open loop, lean mixture, rich mixture, or failed fuel system component.
1334	Crit Scaler OR	Category A	Shutdown
1335	Noncrit Scaler OR	Category B	Warning
1416	Fail To Shutdown	Category C	Warning
1417	Powr Down Error	Category D	Warning	Indicates controller cannot power down because of unknown condition; possible battery drain. Contact an authorized service center.
1433	Emergency Stop	Category D	Shutdown	Pull emergency stop button out; move O/Manual/Auto switch to O; press Fault Acknowledge/Reset button; select Manual or Auto as required.
1434	Remote E-Stop	Category D	Shutdown	See code 1433 to reset.
1435	Low Coolant Temp	Category D	Warning	Check coolant heater power connection/fuse; check for low coolant level and replenish, repairing leaks as needed.
1438	Fail To Crank	Category D	Shutdown	Possible fault with control, speed sensing or starting system. See code 441 for corrective action.
1442	Weak Battery	Category D	Warning	Battery voltage at/below weak-battery trip point during cranking. See code 441 for corrective action.
1443	Battery Failed	Category D	Shutdown	Dead battery, engine will not start. See code 441 for corrective action.
1444	KW Overload	Category B	Warning
1445	Short Circuit	Category A	Shutdown
1446	High AC Voltage	Category A	Shutdown
1447	Low AC Voltage	Category A	Shutdown
1448	Under Frequency	Category D	Shutdown	Check for dirty/plugged air filter and replace; check by disconnecting load and restarting; fuel system may require adjustment; check gaseous fuel delivery; reset and restart.
1449	Over Frequency	Category A	Warning
1452	Gen CB Not Close	Category A	Warning
1453	Gen CB Not Open	Category A	Warning
1459	Reverse Power	Category A	Shutdown
1461	Loss Of Field	Category A	Shutdown
1466	Modem Failure	Category C	Warning
1468	Network Error	Category C	Warning
1469	Speed/Hz Match	Category A	Shutdown
1471	Over Current	Category B	Warning
1472	Over Current	Category A	Shutdown
1477	Over Current	Over Current	Shutdown
2263	Battery Temperature	Battery temperature too high (reaches 55 °C [131 °F]) - battery charger fault message	Warning
2323-2326	Network Fault 5 thru 8	Category E
2327	PTC Fault	Category B	Warning
2329	Low S1 Frequency	Category E	Warning
2331	Low S1 Voltage	Category E	Warning
2335	Excitation Fault	Category A	Shutdown
2336	Memory Error	Category A	Shutdown
2337	Pwr Tran Disabled	Category C	Warning
2338	Pwr Tran Failure	Category C	Warning
2339	Pwr Down Enabled	Category E	Warning
2341	High Control Temp	Category B	Warning
2342	Too Long In Idle (10 min.)	Category E	Warning	Indicates genset has been in Idle mode too long (10 minutes maximum).
2358	High S1 Voltage	Category E	Warning
2396	S1 CB Not Close	Category E	Warning
2397	S1 CB Not Open	Category E	Warning
2966	PTC Timeout	Category C	Warning
2967	Governor Fault	Category C	Warning
2968	AVR Fault	Category C	Warning
2969	LON Failure	Category C	Warning
2972	Field Overload	Category A	Shutdown
Fault 1	Fault 1 (red)	Engine shut down because of a system fault; part of a 10-second time-delay shutdown circuit (customer-wired).	Shutdown
FAULT 1	FAULT 1	Red lamp indicates an undedicated fault; may be field programmed as shutdown or non-shutdown and as timed or non-timed (normally set for timed shutdown).	Shutdown	Nature of fault determined when set installation is designed.
Fault 2	Fault 2 (red)	Engine shut down because of a system fault; part of a non-time-delay shutdown circuit (customer-wired).	Shutdown
FAULT 2	FAULT 2	Red lamp indicates same features as Fault 1 (normally set for non-timed shutdown).	Shutdown	Nature of fault determined when set installation is designed.
HI ENG TEMP	HI ENG TEMP	Red lamp indicates engine has shut down because of critically high engine temperature (above 230 F / 110 C).	Shutdown	Allow engine to cool; check coolant level and airflow; reset control and restart.
High Engine Temperature	High Engine Temperature (red)	Engine shut down due to excessively high coolant temperature (greater than 230°F / 110°C).	Shutdown
LO FUEL	LO FUEL	Yellow (optional) lamp indicates fuel supply pressure is marginally low (5 inches [127 mm] WC or less).	Warning	Check for partially closed shutoff valve or empty propane supply tank; for natural gas check with the gas utility.
LO OIL PRES	LO OIL PRES	Red lamp indicates engine has shut down because of critically low oil pressure (below 25 psi / 172.4 kPa).	Shutdown	Check oil level, lines and filters; replenish if low; reset control and restart.
LOW ENG TEMP	LOW ENG TEMP	Yellow lamp lights if engine temperature is marginally low for starting (70 F / 21 C or lower); may indicate an inoperative coolant heater.	Warning	Check coolant heater operation, power supply, fuse/cord and coolant level.
Low Engine Temperature	Low Engine Temperature (yellow)	Engine temperature less than 65°F (18°C) or 90°F (32°C); possibility engine might not start.	Warning
Low Fuel	Low Fuel (yellow, optional)	Fuel supply pressure is 5 inches (127 mm) WC or less; also indicates operation on secondary fuel supply for dual-fuel sets.	Warning

Showing the first 80 of 93 codes.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Procedures

Gaseous Fuel Adjustments adjustment

⚠ Fuel is highly flammable; do not allow cigarettes, flame, pilot lights, arcing switches or equipment in area or areas sharing ventilation.

Tools: Exhaust gas analyzer (for emission sensitive areas)

Start the engine and let set warm up under partial load (at least 1/4 rated load); start with natural gas if dual fuel.
Connect full rated load and turn power adjust valve to full-rich.
Slowly turn adjust valve towards lean until engine begins to lose speed, then back towards rich until engine carries full load smoothly.
If equipped for natural gas and LPG, switch to LPG by closing manual shutoff valve in the natural gas supply line.
Reconnect full rated load and turn LPG flow adjustment valve clockwise until engine loses speed, then slowly back counterclockwise until engine carries full load smoothly.

Gaseous Fuel System Adjustment adjustment

⚠ Fuel is highly flammable and may cause severe personal injury and property damage. Do not allow cigarettes, flame, pilot lights, arcing switches or equipment in area or areas sharing ventilation.

Tools: Exhaust gas analyzer (for emission sensitive areas)

Start the engine and let the set warm up under a partial load (at least 1/4 rated load); on dual fuel sets start with natural gas.
Connect full rated load and turn the manual fuel valve two turns counterclockwise.
Slowly turn the manual fuel valve clockwise (lean) until the engine begins to lose speed.
Slowly turn it counterclockwise (rich) until the engine carries the full load smoothly.
On dual fuel sets, switch to LPG by closing the manual shutoff valve in the natural gas supply line.
Reconnect full rated load and turn the LPG flow adjustment valve clockwise until the engine begins to lose speed.
Slowly turn it back counterclockwise until the engine carries full load smoothly.

Magnetic Speed Pickup Unit Adjustment adjustment

Measure MPU resistance; replace if not between 1,000 and 1,050 ohms.
With MPU removed, rotate ring gear until a tooth lines up in the center of the mounting hole.
Thread pickup in gently by hand until it just touches the ring gear tooth.
Back the pickup out 1/4 turn and set the locknut.
Verify MPU output voltage at cranking speed is at least 1.5 VAC; replace MPU if less.

Output Voltage Adjustment adjustment

Adjust output voltage plus or minus five percent of nominal voltage using the Voltage Adjust rheostat (optional) on the control panel.
Call your distributor if the required voltage cannot be obtained by this adjustment.

Type A Gaseous Fuel Adjustment (Naturally Aspirated) adjustment

⚠ Gaseous fuels are flammable and explosive

Disconnect all loads, shut down set, and disconnect governor linkage at the carburetor.
Start engine and hold throttle closed by hand to prevent overspeed.
Adjust throttle idle position screw to obtain a frequency of 25-35 Hz.
Turn idle adjusting screw counterclockwise until engine becomes unstable, then clockwise to regain stability.
Reconnect governor linkage.
Connect full rated load and turn main fuel valve to full-rich, then lean until engine loses speed, then back to rich.
If equipped for LPG, switch to LPG and adjust LPG flow valve similarly under full load.

Vibration Isolator Installation and Adjustment Procedure adjustment

Place vibration isolators on the generator set support structure; shim or grout so all isolator bases are within 0.25 inch (6 mm) elevation of each other.
Loosen the side snubber lock nuts so the top plate is free to move vertically and horizontally; verify alignment with base and springs.
Place the generator set onto the isolators while aligning the skid mounting with the threaded isolator hole.
Adjust isolators with the leveling bolt to level the set; nominal clearance between top plate and base is 0.25 inch (6 mm) or greater.
If radiator and engine/alternator are mounted on separate skids, make both skids level for proper fan belt alignment.
If the set is not level, adjust leveling bolts until level with sufficient, roughly equal clearance on all isolators.
Lock the leveling bolt in place with the lock nut.
Leave snubber nuts loose to provide better isolation between the generator set and support structure.

Checking AC Electric System While Running diagnostic

⚠ High voltages are present inside the control box and generator output box when the set is running. Do not open the boxes while the set is running.

Check the frequency meter; generator frequency should be stable and match the nameplate rating.
Turn the phase selector switch to each line-to-line phase selection (L1-L2, L2-L3, L3-L1) and read the AC voltmeter; at no load voltage should match nameplate rating.
Turn the phase selector switch to each phase (L1, L2, L3) and read the AC ammeter; at no load current should be zero.
Push the Reset/Lamp switch; all indicator lamps should light, confirming all bulbs are on.
Have any burned out bulbs replaced.

Verify Overspeed Fault Detection diagnostic

Tools: special tool P/N 420-0604

For Type A sets, move the throttle lever/linkage to increase RPM to the overspeed shutdown range.
For Type B sets, remove the two screws securing the throttle body cover and remove cover.
Use special tool P/N 420-0604 to turn the end of the throttle shaft.
With genset operating at no load, slowly rotate the shaft clockwise until RPM reaches the overspeed limit and shuts down.
Replace the throttle body cover after completing the test.

Battery Connections (Prestart Preparation) installation

⚠ Accidental starting can cause severe personal injury or death.

⚠ Ignition of explosive battery gases can cause severe personal injury or death.

⚠ Ventilate battery area before working on or near battery. Arcing, flames, pilot lights and sparks can ignite battery gas.

Make sure the Run/Off/Auto switch on the control panel is set to Off before connecting battery cables.
Connect the positive battery cable before connecting the negative battery cable to prevent arcing.
Connect the negative (–) battery cable last to prevent arcing.
Service the battery as necessary; connect a separate battery charger if an ATS without built-in charge circuit is installed.

CT Installation Requirements installation

⚠ Each of the operations described should be done only by persons trained and experienced in electrical maintenance.

The CT has a dot on one side; this dot must face toward the generator (conventional current flowing into the dot). A dot also indicates pin 1 of the CT.
CT21 – U load leads (A phase); CT22 – V load leads (B phase); CT23 – W load leads (C phase).
Route the appropriate load wires through each CT.
The CTs have dual secondaries (3 pins). The secondary wire marked 1 connects to pin 1; wire marked 2/3 connects to pin 2 for high voltage gensets or pin 3 for low voltage gensets.

Connecting the Battery to the Generator Set installation

⚠ A battery must not be fitted to a generator set without charge if the specific charge of the electrolyte has fallen below 1.240 during storage.

⚠ Even momentary incorrect connection can cause damage to the electrical system.

Tools: Insulated wrench

Secure the battery. Battery hold-down bolts must be tight, but not over-tight.
Smear the terminals with petroleum jelly, if necessary.
Fit the vents firmly in position and ensure that the battery is clean and dry.
Verify correct polarity when connecting the battery to the set.
Use an insulated wrench to connect the positive generator cable first, followed by the negative cable. Terminal connections must be tight, but not over-tight.

Installation Checklist - Prestart installation

⚠ Improper wiring can cause a fire or electrocution.

Verify wattage capacity sufficient for anticipated load.
Verify at least 3 feet clearance around generator set.
Verify genset located away from flooding.
Check fuel tanks, lines and shutoff valves meet codes and are free of leaks.
Check exhaust system for leaks, secure connections, condensation drain, insulation.
Check AC and DC wiring sizes, insulation, conduits and connections meet codes.
Service engine with oil and coolant.
Verify batteries installed, serviced and charged.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Voltage reconnection

Connection	Leads	Notes
Line 0 or Neutral	N / N / N	Load terminal line designations
Line 1	L1 / A / U	Load terminal line designations
Line 2	L2 / B / V	Load terminal line designations
Line 3	L3 / C / W	Load terminal line designations
TB1 Customer Faults	1=Customer Fault 1, 2=Ground Fault, 3=Low Fuel, 4=Rupture Basin Fault	Default settings, beginning spec J customer input #4 not available
TB1 Customer Relays	1=Common Warning, 2=Common Shutdown, 3=Not in Auto, 4=Ready to Load	Default settings; NO contacts rated 2 amps at 30 VDC

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Aftermarket parts that fit this engine

DKS20DT FridayParts $298.72 HC3Z19703B FridayParts $298.72

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Common questions

What is the oil capacity of the Ford V-10 6.8L?

The Ford V-10 6.8L engine has an oil capacity of 5.5 liters.

What is the displacement of the Ford V-10 6.8L?

The Ford V-10 6.8L has a displacement of 6.8 liters with 10 cylinders.

Which generators use the Ford V-10 6.8L engine?

The Ford V-10 6.8L powers 2 generator set(s), including Cummins/Onan GGHG, Cummins/Onan GGHH.

What is a common problem with the Ford V-10 6.8L engine?

A commonly reported issue on generators using the Ford V-10 6.8L is: The engine does not crank in Run mode. Cause: The Emergency Stop switch has been used. (The switch button is lit.). Fix: Pull the Emergency Switch button. To reset the engine control, push the Run-Stop-Remote switch to Stop and the Reset switch to Reset. Then push the Run-Stop-Remote switch to Run to start the genset..