I know that there are ALOT of threads about this topic, but I am having a difficult time with mine. I have tested the relay and it is fine. When I attempted to Ohm the plugs by taking the connectors loose on the valve covers. I was not able to get any reading (even on the common tab) on either side of the engine. What I am I doing wrong? Can anyone point me to a thread that tells me more on this?

This all came up when I tried to start my truck on our first cold morning here in SC. It took a while and billowed white smoke for about 1 min once it finally fired. I found one problem was that I was only running on one battery due to a bad connection on one of them. Fixed that and both batteries are fine. HELP!

 

Here's some notes I copied a few years ago from another forum:

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.

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.

· 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.

 

Thanks! I will give this a try tomorrow morning while she is still good and cold.

 

A member here, Megawatt00 (Jim) is very fluent with our glowplug system. You might want to shoot him a PM and pick his brain.

 

Were you sure the negative lead was grounded on something that will actually work?

 

The 9-pin plug is wired as follows:

I hope that this helps.



G G I I C I I G G

G=Glow Plug +
I = Injector +
C= Injector Common

The injectors fire with a 115VDC signal from the IDM. Do Not pierce the wires to test.

Test between "I" and "C" to test the injectors, should be less than 5.0 Ohms.

To check glow plugs Test between "G" and battery ground. Should be between 0.6 and 2.0 Ohms

 

No, actually I am not sure. I grounded first to the negative battery lead and then I tried the alternator. I am about to try the engine block now. Any suggestions?

 

Thanks Jim this clears a bit up for me. I was not using a "true ground" I think. I will go and try this now.

 

I used the negative battery post as a ground as recommended and here are the results.

Back Passenger side of Harness
infinity
1.7
infinity
infinity
Front Passenger Side

Back Driver side
infinity
infinity
6.1
infinity
Front driver side

 

It appears that I have one good glowplug. Any recommendations on manufacturers and/or techniques for replacement?

 

Buy the Motorcraft brand glowplugs ZD-11's. They are the best out there. Give me a minute and I'll look up some directions for the procedure to replace them.

 

Here's a thread to help.

Read the first post:

https://www.ford-trucks.com/forums/4...ke-thread.html

 

Hey guys...Im not trying to high jack this thread(well maybe so but its about glow plugs and what not) but how often do glow plugs need to be replaced? I replaced mine last winter but now that its getting cold, Im getting ALOT of white smoke at start up( stinky smoke like raw fuel),its not really cranking that much longer but it still smokes. I also replaced the GPR as well,I know its working cause when you turn the switch on the int. light gets brighter after a min. or min. and a half. Again sorry for the but maybe we can all get some new info.
Thx, Schlepprock

 

The Bosch glowplugs are good also. Stay away from the Autolites they swell up during use and break off when you try to remove them. If you don't want practice removing your cylinder heads, stick with the Motorcraft or Bosch.

Austin

 

I would suggest going through the procedure to re-check the GPR before opening up the V/C's. Just a thought.