ok guys heres the deal. i got the go ahead from cookie about making a sticky thread on changing glow plugs, gpr, ohm readings, finding your block heater cord, white smoke and anything valuable you can add.
the reason i thought of this was last fall/ winter myself and a million others had problems with our trucks.
so hopefully we can make this thread a one stop shop for all who require assistance. and also not see 100 threads a day about gp's.



removal of glow plugs(if there was autolites installed before you will probably have issues trying to remove them)
1. a deepwell very thin walled 10mm socket is almost a must for removal of glow plugs!!!!(if it is thick it will hit your rocker arm/ pushrod and get stuck)
2. a little medicine dropper to suck the oil out of the recessed area on top of the glow plug so it doesn't run into your cylinder when you pull the glow plug.
you will also need a torque wrench that goes as low as 14 ft lbs.
the way to get the passenger side valve cover off you gotta lift the firewall end up first then the front side of it to get it out. not to bad.
that back bolt takes some work a shorty 13mm and a 3/8 in drive ratchet and a lot of ratcheting motions.

a few part numbers
glow plugs
(AutoZone) ZD-10 or ZD-11 (Beru plugs) Autozone no longer carries Beru Glow plugs
(Ford) F4TZ-12A342-A
(International) 1820697C2
i cant emphasize this enough. Buy only Motorcraft/Beru glow plugs

[size=2]Glow Plug Deactivation Kit (opens at 115 degrees coolant temp and disables the glow plugs)
(International) 1831142C91

Glow Plug Relay
(Allied Electronics) 576-1078 (Stancor Heavy Duty 586-902)
(AutoZone) MR99
(Ford) F7TZ-12B533-CA (94-96 with pigtail)
(Ford) F81Z-12B533-AC (96-early 2000 w/o pigtail)
(International) 1807230C2
(International) 1826634C94
(Napa) GPR-109 <-----20 bucks at napa

Glow Plug Relay shunt; Required for GP monitor circuit; 97 CA
(Ford) F7TZ-12B533-B

GPR:
is located on passenger side of valley by the fuel filter housing. looks like a starter relay.

WHITE SMOKE:
unburnt fuel. if you have this on a cold start up you probably have 1 or more gp's not working.

BLOCK HEATER CORD:
orange cord that comes out of engine right above oil filter housing.
follow it forward. it is probably in your bumper somewhere.
if you see no orange cord you probably dont have one on your truck.

i am sure i missed lots of things . but that is where you come in. please dont repost something that is already here.
i definitely need someone to post on ohm reading and the testing portion.

if you find in the process of changing out your glow plugs you have the following: burnt uvc wiring, burnt connector on gaskets, or external plug damage click here for part #'s, cost and what it looks like and cheapest place i found to order part from.
thanks in advance to all who contribute and good luck to all that take on this task.

also wouldn't be a bad idea if someone could dig up one of there old writeups that had a glowplug stuck. copy and paste the actual content into this post to avoid having to click on a whole bunch of links.

 

The 99 and newer engines
Each valve cover has an electrical connection; each connector has 9 pins.

G G I I C I I G G
The two outer pins on each side connect to the glowplugs (G) under the cover.
The next two pins in connect to the injector (I) coils.
The center pin is a common (C) for the injectors coils.

You'll need a multi meter that can measure ohms.
Connect one lead (usually the balck one) to a good ground.
Then probe each of the outer pins on the connector.
Good glow plugs usually measure between .8 ohms to 1.5 ohms.
Some may be outside of that, but won't stray too far.
Bad plugs can measure anywhere above 20 ohms, for instance, when I replaced mine, I had three plugs that measured 800 ohms, two that where open or infinite resistance, and one that was around 600 ohms.

 

I think you might emphasize 90% of glow plug related issure are GPR related and not so much GP related. I would hate to see all these guys go tearing into their trucks only to relaize its a 5 minute job to replace the GPR

 

When you got to Napa tell them you need a part # GRP-109. They are around $20. If you ask for one by year and model of truck youll pay closer to $60 or $70 for one.

I put a a Stancor 586-902 contactor in mine. I got it from Mouser.com for under $45. It is about 3 times the size of the stock GPR.

 

The other one is the intake heater relay.

 

Checking glow plugs with test light-

For anyone not fluent in multimeters, connect the ground clip of a test light to a battery positive.

touch the pointed end to a glow plug tip or the wire that goes to the tip.

Light comes on-good plug.

No light- bad plug

This test can be performed through the valve cover gasket connectors.

94 to 97 has 2 connectors per valve cover with a pinout of G I C I G
99 and up has 1 connector in each valve cover with a pinout of G G I I C I I G G

G - glow plug
I - Injector coil
C - Common injector coil

 

I've got one other tip.

When you are putting the valve covers back on, have a final look before putting the bolts in. The last time i did the glow plug thing, i just happened to hit the passenger side rear injector wire harness retainer with the valve cover. It had also knocked the wiring pigtail out of that injector too. I didn't look and when i fired it up, it had an obvious miss under 1500 rpm.

Unfortunately, i started the diagnosis with the driver's side, so i got lots of practice in r&ring the valve covers. It's pretty quick with all the extra practice. I found the best method is to set the cover in place, then lift up on the top edge and inspect the wiring. When you're satisfied all is good, bolt it down.

I will say this though, during the first test drive, a 7 cylinder engine will still run quite well at 70 mph, it was only noticible under 1500 rpms. I wonder how many unfueled cylinders would really keep these beasts from moving? Other funny thing is it never tripped the check engine light.

 

I found this in the link below. If you go there you can see the picture of the GPR that is mentioned in the first line.
https://www.ford-trucks.com/forums/s...d.php?t=426789

I have attached a small photo of the glow plug relay, as seen from looking from the front of the truck. (Goto link above to see the picture)

The large terminal on the left with a rubber boot over it goes directly to the batteries. It has +12 volts all the time.

The other large terminal, without a boot, is the switched +12 volts that is fed to the glow plugs when they are supposed to be on. That current gets fed to the glow plugs through the brown and yellow wires (below). I don't know where the blue wire goes. Anybody got those factory wiring diagrams?

The smaller terminal at the bottom has no voltage when the key is off, but gets +12 volts any time the key is on, engine running or not. It is the incoming current supply for the relay's coil.

The other smaller terminal, closer to the firewall, is the other side of the relay's coil. It is looking for a ground to activate the relay. When the key is first turned on, and glow plug heat is called for by the PCM (the engine computer), the PCM outputs a ground, thereby causing current to flow through the relay's coil, activating the relay, and sending current (at +12 volts) to the glow plugs. When glow plug heat is no longer called for, the ground that is output by the PCM goes "open", causing the relay to turn off. If you put a volt meter on this pin after the relay opens, you will see +12 volts here, too. Why? The wire in the relay's coil is feeding it to your volt meter.

If you short this terminal to ground through a switch, you can manually control the current to the glow plugs any time the key is on.

Since the winter weather is usually not that cold here in Southern California, I intend to install a switch inside the cab that opens the connection to this terminal. That will allow the timer to control the glow plugs normally ONLY when I want it to. Otherwise, when I don't need the glow plugs to be heated, I'll save myself the current drain on the batteries.

You could also wire a momentary-contact push button switch in the cab and have glow plugs only when you push the button, and complete manual control if you want it. I wouldn't use a toggle switch, as it could be forgotten and the glow plugs would be on all the time. Not a good thing.

Pop

 

GPR 109

 

Exactly how much (or for how long) smoke is considered "normal" at cold start?. Lets say temp is 40 degrees. Is it actually possible to have none at all? Mine pumps out white for maybe 10 seconds, or about a garageful, after that there is still some brown, not all that visible smoke coming almost indefinitely or until I start driving, when all smoke disappears entirely. It's a -97 PSD w/85000 miles and probably original plugs and all. No other performance problems.

 

that is fine....
if you wait about 20 seconds after you turn the key you should have almost none....
if you still do you may have a gpr on its way out or 1 or 2 plugs bad...

 

When I replaced my gp's I made the mistake of allowing some oil from the rail to get inot the cylinders. VERY BAD THING TO DO. Not realizing it, I finished putting everything back together and when I tried to start it, it wouldn't even turn over, it was hydro locked. Fortunately it didn't do any damage. I had to start all over and pull each gp out and clear the cylinders of the oil. So my recommendation is after you pull out the glow plug, just insert a long clear rubber hose into the cylinder and suck on it like a straw or hook it up to a shop vacuum cleaner and make sure there isn't any oil in the cylinder.

We all learn from each others mistakes and hopefully don't repeat them.

 

Great thread! I had to replace my glow plug relay this week, and I've got a couple of things out of it:

First, you cannot tell by the in dash voltmeter if the GPR is bad or the glow plugs themselves are bad (if you still have a voltage drop)

Second, the GPR-109 and GPR-110 are almost identical, but at $23, the GPR-109 is cheaper (NAPA), but the manuals said I needed the 110 (for a 1997 model). It took some figuring out, but the 110 is apparently rated for a longer load time than the 109 - this is important for folks like me who live in colder climates and have the relay energized for longer periods of time. Otherwise, they are nearly identical, they exception being how the mounting tabs are rotated.

I was lucky when I replaced my relay. When I was removing the electrical connections, the battery lead came completely out of the old relay. I was pretty happy that I had a "smoking gun" in my hands since it was 5 degrees out (-10 with the wind chill)! And in case anybody was wondering, if you drop one of the smaller nuts (due to frozen fingers or something) and can't find it, the nut on the field terminal of an old Ford alternator fits perfect.

 

if nothing is burnt on the electrical connections and they are not messed up they are reusable gaskets.

 

the bulbs come out of the back of it. look at your black dash beezel, there is 2 removable strips on each side, pop em out, undo the 8mm (?) screws. pop off the headlight ****, pull beezel away from dash, diconnect wiring harness from back of wts cluster, unscrew and remove the little box. there is 4 bulbs or so in there. replace em.