glowplug replacement questions

[elrojo63]

My truck's been on the downhill with cold starting for a while now. Today it wouldn't start up and I ended up cycling the gp and cranking so much battery died. I checked the relay and it get's 13v on both sides of the gp relay for about 8 seconds. Truck smokes a huge white cloud when it cranks now and literally smells like I'm in a diesel tank so I'm going with this is a gp problem.

What glowplug should i replace it with? Is motorcraft the best or does bosh or autolite make somethign better?

Any tips for installation? Is there anything i can put on so i don't have to worry about a seized plug sometime down the road?

[Coalroller68]

I use all motorcraft ZD-11 gp's, i have put these in many trucks for myself and neighbors and nobody has had a problem with them, all have worked great, As for making sure it doesnt seize up, I dont know of anything you can do. I have never really heard of a motorcraft glow plug getting stuck so you should be fine.

[elrojo63]

I was reading a lot of threads about people having problems pulling out some plugs and ending up having to pull the head. Maybe that's just a problem with the original ones. Have you ever had to put plugs on a truck more than once?

[elrojo63]

i was reading a lot of threads about people having problems pulling out some plugs and ending up having to pull the head. Maybe that's just a problem with the original ones. Have you ever had to put plugs on a truck more than once?

[Coalroller68]

Yeah that happens if the plug gets too carboned up, you cant pull it out so the head has to come off. I have never had to replace them more than once yet. my originals on my red 99 went 210k, others i just replaced when i was doing other work.

[elrojo63]

sorry about the multiple responses. My phone kept acting like it hadn't posted the reply. I've got 260k on my truck and i don't know when they've last been changed if ever. Is there a way to individually test each glow plug once the valve cover is off or should i replace all 8 while I'm in there. A new set of autolites from advance auto is $80.

[jesilvas]

Yea read this.
"Start with the troubleshooting below. If it starts fine with the block heater plugged in than you probably have problems with the GP system. Changing the GP's are easy, pulling the VC's is most of the work. Most of the time it is just the GPR, and if that is bad I highly suggest going with the Stancor model (586-902, IIRC)

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.
· 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.
· 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.

If your GPR is bad you can use the factory replacement for around $75, Napa's GP110 is close to this price maybe $10 cheaper. But you can get a GPR 109 from Napa for around $22.00 This is the same exact relay as the GP110 except the mounting holes are rotated 180 degrees, which is no big deal as the wires stretch just fine.
Now if you are tired of replacing your GPR and want a H.D. alternative may I suggest the Stancor 586-902. This is a large relay and it can truly handle the large AMP draw our trucks call for at start up. Gopher Electronics has these for under $40. I know several folks that live way up North (Alaska, Canada) where they know about serious cold starts and they all swear by the Stancor. I am very happy with mine, I believe I have pics of mine installed in my webshots.

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. Photo of disconnecting one and 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.
Take Care
Kevin"
Glow Plugs
Also, get the Motorcraft plugs. All other kinds really aren't as good. Especially Bosch's. Some people have used Autolites, but why argue with the OEM plugs that have lasted for so long on so many trucks.

[Fort Collins PSD]

Motorcraft glow plugs are great and cost about 26 per plug from your local stealership. You could also get plugs from an International Dealership and they cost 5-10 dollars less then motorcraft. I figure that ford buys them from International so why not save some money. Also if your changing out the glow plugs change the glow plug/fuel injector harness. They are like 38 per harness but cheap insurance for the long one and they are right there anyway

[Matt P]

I will only ever put motorcraft glow plugs in a truck, dont use autolites, those can swell and get stuck in the heads, the motorcraft/beru ones are the best

[elrojo63]

thanks guys! I'll test the resistance this morning and see which ones are bad. The relay is good. I get 12-13 volts every time in cycle the key