1994.5 - 1998 Ford F-250, F-350, F-Super Duty 1999 - 2003 Ford F-250, F-350, F-450, F-550 at sight Duty 2000 - 2003 Ford Excursion 2000 - 2003 Ford F-650, F-750 all E-Series models

Signs of light plug related difficulties include tough starting, extreme cranking, and also a stormy idle because that a short period after starting the engine the smooths out as the engine warms up. Light plug troubles are especially prominent in colder weather together the engine relies more heavily on a beginning aid 보다 it does in warmer conditions. The bright plugs top top a 7.3L power Stroke are situated beneath the valve covers and also just next to each separation, personal, instance fuel injector.

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Before instead of the bright plugs verify the the trouble is not related to a bright plug relay or high push oil problem. A glow plug relay that chatters (clicks on and off rapidly) should be replaced. Likewise, if you perform not audibly finding the bright plug relay engaging when the key is turned come the "run" place (initiating bright plug preheat cycle), the glow plugs space not receiving power; the relay renders a distinct clicking sound as soon as it is energized. White smoke gift emitted out of the tailpipe throughout cranking may suggest a bright plug related trouble as the engine is receiving fuel yet there is a absence of warm to start auto-ignition. Because that a tough start/no start condition with no smoke, verify the the ICP and also IPR valve room functioning properly. The device requires a minimum ~ 500 psi the oil press in order come fire one injector.

7.3L power Stroke light Plug components List

We highly recommend that you use real Motorcraft ZD-11 (Ford p/n F4TZ-12A342-BA) glow plugs. Aftermarket light plugs have actually garnered a background of failure and/or a significantly shorter life 보다 the OEM units. Comes to with aftermarket light plugs include the tips swelling and breaking turn off in the cylinder during removal. Additionally, replace all 8 glow plugs at once - they room not horrible expensive. If the valve covers room removed, it is way to re-torque the rocker eight pedestals and also injector hold-down bolts, both that which have a propensity to loosen over time.

Part Description

Part Number(s)


Glow plug

Motorcraft ZD-11


Glow plug relay

Motorcraft DY-861 Ford F81Z-12B533-AC


Glow plug harness

1994 - 1997

Ford F4TZ-9D930-K


1999 - 2003

Ford F81Z-9D930-AB

Valve covering gasket

1994 - 1997

Ford F4TZ-6584-A

1999 - 2003

Ford F81Z-6584-AA

<1>The bright plug and also fuel injector harness is included into the valve cover gasket on every 7.3L power Stroke diesels. The harness deserve to be replaced independent the the valve cover gasket, yet the pass-through connector top top the valve covering gasket is a well-known failure allude and need to be tested prior to reusing.



• eliminate the clamp the holds the dipstick pipe to the dipstick bracket (10 mm socket).

• eliminate the dipstick tube bracket, which is hosted in location by 2 studs (1/2" hex head).

• eliminate the valve sheathe bolts using a 1/2" socket, then remove the valve cover native the engine. The rearmost valve sheathe bolt (against the firewall) is an overwhelming to accessibility - a 1/2" shallow socket attached come a flex share (universal joint, wobbly) complied with by a 6"- 8" extension will provide you the angle and also reach to eliminate it. Be cautious not to damage the valve sheathe gasket, which is re-usable and also contains an combined wiring harness.



• eliminate the electrical connector indigenous the height of the bright plug and also carefully move it out of the way. A pair of needle nose pliers is helpful for slipping turn off the connector.

• use a clean rag to tenderness dab the engine oil around the glow plug. This will certainly minimize the quantity of oil the seeps into the cylinder once the light plug is removed.

• usage a 1/4" drive, 10 mm deep socket with a little extension to ease the glow plug. You will certainly not be able to fully remove the light plug, as the socket will certainly hang up on the rocker arm (if you loosen too far and also can not eliminate your socket, simply tighten the bright plug until you deserve to remove it).


• once you have actually loosened the glow plug, on slide a 6" ar of 1/4" fuel/vacuum hose over the exposed guideline of the bright plug. Use this to loosen the light plug fully and remove it.

• If your hose simply spins ~ above the glow plug and is not successful at removing it, climate you did no loosen it enough with her socket. Attempt to ease the light plug as lot as possible with the socket when still being able to eliminate it without hitting the rocker arm. • IMPORTANT: it is in extremely careful not come drop any kind of tools into the rocker arm journals, together it will certainly be extremely complicated to effort to fish them out.

• through the old light plug removed, installation of the new one is reverse. Slip the brand-new glow plug right into your 1/4" hose and also start to tighten it by hand, then end up using a 10 mm socket.

• Torque light plugs to 124 in-lbs (14 N-m) and then reinstall the electric connector, making sure it seat properly.

• change one light plug in ~ a time and work front-to-back (or back-to-front) so the you have the right to keep track of i beg your pardon ones have actually been replaced.

• while you have actually the valve sheathe off, that is way to torque under the injector hold downs and rocker eight pedestals. Speak the rocker arm pedestals to 20 ft-lbs (8 mm, 12 suggest socket) and also the injector organize downs come 120 in-lbs (6 mm Allen).

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• Reinstall the valve cover, torquing the bolts come 97 in-lb (11 N-m) in an alternative pattern, then reinstall the dipstick tube bracket and clamp.

• measures for the driver side is identical to that of the passenger next - ease the old glow plug through a 10 mm deep socket, remove with 1/4" fuel/vacuum hose, and install brand-new one in turning back order.

TIP: use an investigate mirror and flashlight come ensure that the electric connectors space properly set up on the glow plugs closest come the firewall, together it is simple to wedge the connector between the push rod and glow plug, offering the false feeling that the connector is seated when it is without doubt not..