Thought I'd post this as a sticky thread now that cold weather is on us.
How to check Glow Plug System
To check the Glow Plug Relay (GPR)
· Be sure the engine is cold, so that the PCM will tell the GPR to turn on. If the engine is hot, you won’t have as much time to check. (if oil temp is below 130F, it won't turn on at all)
· Locate the GPR – Its behind the fuel filter on top of the engine, a little bit toward the passenger side of the valley. There may be two relays there. If so, the rear one is the GPR. It will have two fairly large wires (yellow and brown) connected to one of the large posts. (circled on this photo)
Photo credit F350_6
· With your multitmeter set to DC volts, and 15 V range (if not autoranging), clip the positive (red) lead to the output terminal (with yellow and brown wires connected), and the negative (black) lead to a good ground point (like the battery ground terminal or someplace metal directly on the engine block.)
· Turn the key to ON (do not start)
· If your GPR is good, it should click, and you’ll see 11 volts or so on your meter, then, depending on temperature, it will click off up to 2 minutes later. You should do this a couple of times to make sure it consistently makes the connection.
· If you don’t get voltage with this test, confirm by retesting as follows.
· Remove the two small wires from the smaller two of the four GPR terminals.
· With jumper wires, apply voltage from the battery across the two small terminals. If your voltmeter now reads voltage on the output terminal, your GPR is OK, and your problem is in the PCM circuit that tells the GPR to activate.
GPR for 99 & up 7.3L
Ford F81Z-12B533-AC
NAPA GPR#109 (mounts 90 deg out of rotation from original)
Carquest #RY-175 (clone of GPR#109)
Autozone Sorensen MR-99 (also clone of GPR #109 I think)
International #1831646C1 (Identical to the one you'll get from Ford) ~$25-$30
To check Glow Plugs.
· Remove the electrical connector on the inboard side of valve cover at the gasket. Press down on the top of the connector latch and pry gently with a screwdriver. Disconnecting VC harness connector.
Another photo of it loose.
· There will be 9 pins on the valve cover gasket where you removed the connector. The two pins furthest forward and the two pins furthest back are for your glow plugs.
· With your multimeter set to resistance (ohms) and low range (single digits) if not autoranging, clip the negative (black) lead to a good ground point.
· Probe each of the 4 outer pins individually with the positive (red) lead, noting the resistance. Good glow plugs will have a resistance between 0.6 and 2 ohms. If you get infinite resistance on any glow plug, that one is either bad or the connector under the valve cover has come loose.
Last edited by klhansen; 03-03-2010 at 08:32 PM.
Reason: Inserted Photos & added GPR part #'s, added photo of GPR location
Oooohhhhh. This is awesome. We've had Ford diesels for years, and are just now trying to figure out what we can do on our own! (I'm sick of paying the "stealer" his crazy rates) This kind of troubleshooting is AWESOME! Please, please, please keep it coming!!
Is there any way to post diagrams? I know, I should just get the repair manual...... But I'm still looking for the fuel filter....
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2000 F350, CC, 4x4, auto.
All stock for now
I know what you mean. The owner's manual on my 99 doesn't even tell you where the filter is. [img]/ubbthreads/images/graemlins/mad.gif[/img]
I eventually found it under the "Powerstroke" cover on top of the engine. We were all noobies once. [img]/ubbthreads/images/graemlins/grin.gif[/img]
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This is information that needs to be added to the beginning of the otherwise great write-up in the "The TheDieselStop.com 1999-up FAQ" I copied this off and had it in hand when I went to R&R the fuel filter but my wife and I both looked for quite some time before I figured out where it was located.
Thanks "klhansen" and "8V92TTA" for the great write-ups and the additional diagrams. I'll add all this info to my "book" of PSD knowledge for use in the future. [img]/ubbthreads/images/graemlins/cool.gif[/img]
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Dan.
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... 2002, F-350, Lariat, Oxford White, CC, 4X4, DRW, 172 WB, PSD, Auto Trans, Dana 60 front & 80 rear 4.10 axles, Camper Pkg, Dual Alt's, Off-Road Pkg, Class ? Hitch, Tubular Steps, ESOF, Adj. Pedals, Line-X bedliner, Three ISSPRO gauges, BrakeSmart brake controller, Oilguard bypass oil filter, Heater hose ball valve, Magnefine tranny filter, Magnefine power steering/power brakes filter, Baldwin coolant filter, Reese 20K 5'er hitch, Fumoto oil drain valve, Rancho RS9000X shocks, Centramatic wheel balancers on front & Rear, AIS air filter/intake system, Blue Ox Bedsaver, Truck Covers USA's "rigid roll top bed cover".
Will it still start in warm weather with a faulty GPR? Do they completely fail or get tempermental??? Good Stuff [img]/ubbthreads/images/graemlins/cool.gif[/img]
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F 350 2000 4X4 Wicked Wheel, Triple Pillar Guage (Pyro, Trans Temp, and Boost), BRV+ Boost Regulator, DP 4 POS Tuner Stock, 40 Tow, 80 Econo, and 120 Race, Fuel Reg. Shim + Fuel Pressure Gauge, and K & N FIPK intake.
What if you have a CA truck and have the Glow Plug Controller instead of the Glow Plug Relay? How would I go about testing this thing? It has 2 pigtail plugs goin into it...Thanks!
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'01 PSD 7.3L Excursion Limited EBM1, 8.5" lift, rear Deavers, 37" PJs, 16x10 Black Rockcrawlers, ORU dual shock hoops, Rancho 9ks all around, Magnaflow T304 system w/5" tip, FTVB w/50/50 mix regular Mercon/Mobil 1 in trans, Mobil 1 PS flush, Tri-pillar loaded w/Di PriCols (EGT,trans, boost), TS 4 pos. switch chip, ConFerr Rack, Cobra CB, TT/sig mirror conversion, 170 hi-amp alt, Hi Lift equipped, UltraDuty rearend cover w/Mobil 1 syn. w/OE friction modifier, Hutch/ITP intank mod, 2 Micron Dahl PrePump, FPR Jack shim mod@ 70psi, 203 deg T-stat & billet housing, Hawk pads, Centric rotors, Valvoline synthetic brake fluid 105.5k so far...
Recent mod: Dieselsite Coolant filter 4/21/05 @ 1100 @72 degs. F ambient temp ;P
Currently sittign in the driveway with a blown up tranny Dirty X Clean X
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What if you have a CA truck and have the Glow Plug Controller instead of the Glow Plug Relay? How would I go about testing this thing? It has 2 pigtail plugs goin into it...Thanks!
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As far as I know, the GP Controller talks to the PCM and throw codes whenever it has a problem, so you best approach there would be to scan it with a good scan tool. You might be able to pull the GP harness off and monitor the GP pins on the harness (front two and back two) for voltage at first Key On similar to the GPR testing. I think the GP controller contains a series of solid state relays, one for each GP.
Sorry, don't have any direct experience with those animals.
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First truck -- 1929 Model A Ford pickup, restored from ground up. Wish I still had it!
99.5 F250 PSD Supercab LB 4x4, ZF-6 w/SB Con OFE, 3.73LS, Boost & pyro gauges, Swamps S175/146 injectors, Jody's 80 HP Econo PCM (classic version), AIS, coolant filter w/"hokum" bracket, regulated return, heated mirror mod,lighted cupholder,Marinco heater plug-in.
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To check Glow Plugs.
· Remove the electrical connector on the inboard side of valve cover at the gasket.
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Ok, I probably picked the worst day to try to do this because it is COLD here. How in the #$!@% do you get the connector off? I was not able to get it off and was afraid of breaking it.
They are tough little buggers, and hard to get to.
Push down on the lump on the center of the connector to release the hooks just to each side of that lump and at the same time use a small screwdriver to gently pry the connector apart at each end. Stick the screwdriver in at the joint where the seal is and twist.
Hope that helps. I'll be getting at mine in the next couple of days and will try to post a picture.
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First truck -- 1929 Model A Ford pickup, restored from ground up. Wish I still had it!
99.5 F250 PSD Supercab LB 4x4, ZF-6 w/SB Con OFE, 3.73LS, Boost & pyro gauges, Swamps S175/146 injectors, Jody's 80 HP Econo PCM (classic version), AIS, coolant filter w/"hokum" bracket, regulated return, heated mirror mod,lighted cupholder,Marinco heater plug-in.
[ QUOTE ]
They are tough little buggers, and hard to get to.
Push down on the lump on the center of the connector to release the hooks just to each side of that lump and at the same time use a small screwdriver to gently pry the connector apart at each end. Stick the screwdriver in at the joint where the seal is and twist.
Hope that helps. I'll be getting at mine in the next couple of days and will try to post a picture.
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Mine was being difficult to get off, but I discovered I could just stick the multimeter's probe in next to the wire to get a reading, without unplugging the connector.
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Another photo of it loose.
), AIS, 
105.5k so far...
Linear Mode
