Correct Glow Plug Testing Procedure Question.
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Elder User
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From: Morgantown, WV
Correct Glow Plug Testing Procedure Question.
I want to make sure that I am testing my Motorcraft ZD-1A Glow Plugs correctly. This is on a 1985 6.9l Diesel.
Step 1. I have hooked one end of my test light to the positive cable on my battery,
Step 2. Remove the Glow Plug Connector for each Glow Plug,
Step 3. Then I take the other test light connector and touch that to the "TIP ONLY" of the glow plug
If the plug is good, the light should light up. What I have noticed on every set of my new glow plugs is that the light never lights up, but if you take Step 3 and touch the test light connector to the base of the Glow Plug, then the light lights up, and if I touch it to the "TIP ONLY" I have never ever gotten the light to light up. Please confirm that this is correct for me.
Thanks.
Step 1. I have hooked one end of my test light to the positive cable on my battery,
Step 2. Remove the Glow Plug Connector for each Glow Plug,
Step 3. Then I take the other test light connector and touch that to the "TIP ONLY" of the glow plug
If the plug is good, the light should light up. What I have noticed on every set of my new glow plugs is that the light never lights up, but if you take Step 3 and touch the test light connector to the base of the Glow Plug, then the light lights up, and if I touch it to the "TIP ONLY" I have never ever gotten the light to light up. Please confirm that this is correct for me.
Thanks.
Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
When you touch the spade connector, you are testing the heating element in the glow plug.
When you touch the base, you are grounding to the engine block, which is where the heating element grounds to.
When you touch the base, you are grounding to the engine block, which is where the heating element grounds to.
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Joined: Dec 2007
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From: Colorado Springs, CO
Glokem45, You are correct in what you mentioned in your test procedure above. Basically you are completing the circut with the test-light rather than the glow-plug harness. If your light isn't coming on, then it would seem that for some reason you are not completing the circut. It is basically the same as connecting a wire directly from the battery to the glow-plug, only this wire happens to have a light in the middle of it.
Did you say these are all new glow-plugs? Test them without the engine being involved. clamp your test light to the positive lead on the battery, lay the GP on the negative post so that the threads of the GP are on the post, then touch the test light to the spade connector. simple circut, should work. (careful, when you complete the circut the GP will get HOT! Hold onto it with pliers, not fingers).
Did you say these are all new glow-plugs? Test them without the engine being involved. clamp your test light to the positive lead on the battery, lay the GP on the negative post so that the threads of the GP are on the post, then touch the test light to the spade connector. simple circut, should work. (careful, when you complete the circut the GP will get HOT! Hold onto it with pliers, not fingers).
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Elder User
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From: Morgantown, WV
When I test the GP's, they are mounted in the block. Even when I bought my last new set of ZD-1A's, I never got the test light to light up when touching them to the blade of the GP. I am not sure what else to try, b/c my multimeter didn't read any ohm's either.
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Joined: Dec 2007
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From: Colorado Springs, CO
How are you testing the GP's with the multimeter?
Should be: one lead on base or block, the other lead on spade connector.
If you are testing the GP's out of the block, then one lead goes onto the element (inside engine) and the other lead goes on the spade connector. On my brand new GP's, I was able to ohm out to 0.0 at the tip of the GP, the used ones I took out would only ohm to 0 when I was much closer to the threaded base, or wouldn't ohm out at all.
Should be: one lead on base or block, the other lead on spade connector.
If you are testing the GP's out of the block, then one lead goes onto the element (inside engine) and the other lead goes on the spade connector. On my brand new GP's, I was able to ohm out to 0.0 at the tip of the GP, the used ones I took out would only ohm to 0 when I was much closer to the threaded base, or wouldn't ohm out at all.
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From: Morgantown, WV
When using the multimeter, I was touching the negative battery post or on the engine block and then the other contact was on the GP Blade. I believe you are supposed to get 0.5 ohm if they are working correctly, or am I not quoting that correctly?
I will try measuring the GP ohm's with a lead on the base of the GP and the other lead on the blade of the GP and see what I get. Of course there is a ton of room around the GP's to work on stuff, right?
I will try measuring the GP ohm's with a lead on the base of the GP and the other lead on the blade of the GP and see what I get. Of course there is a ton of room around the GP's to work on stuff, right?
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From: Virginia
You are testing them correctly. Looks like they are burnt up for some reason. Possibly the controller burnt them up? I would pull one out and see what it looks like.
After you use a testlight and a meter for awhile and build your confidence up, you can start believing what it's telling you. You checked it several times, and even used a meter as a back-up. I believe they are burnt out.
After you use a testlight and a meter for awhile and build your confidence up, you can start believing what it's telling you. You checked it several times, and even used a meter as a back-up. I believe they are burnt out.
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From: Morgantown, WV
Ok, this evening I got home from work and I tested the front two plugs with the Multimeter. I set the multimeter to 200 ohm's, and I tested this by touching the two leads together and it was shooting b/w 0.4 - 0.6 ohms. So I then took one lead and touched the base of the Glow Plug and took the other lead and touched it to the Glow Plug tip/blade, and I got no reading at all on the front 2 Glow Plugs. I don't really feel like testing the other 6 of them b/c I am sure the rest of them are dead.
Is it safe to say that the front two GP's are dead considering I got no reading at all on the Multimeter? I measured my batteries just for fun, and the multimeter was showing 12.57 volts on both batteries. I also measured the volts coming in and going out of the Starter Relay and it was reading 12.57 volts as well. I ran out of light to test out the controller or the individual GP connectors, but I will tomorrow hopefully.
Any other ideas?
Is it safe to say that the front two GP's are dead considering I got no reading at all on the Multimeter? I measured my batteries just for fun, and the multimeter was showing 12.57 volts on both batteries. I also measured the volts coming in and going out of the Starter Relay and it was reading 12.57 volts as well. I ran out of light to test out the controller or the individual GP connectors, but I will tomorrow hopefully.
Any other ideas?
Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
Is the multimeter you are using digital?
.5 ohms is very close to a dead short.
Some cheap meters just show 0 ohm's or dead short when testing glow plugs.
An analog meter with a needle scale, is going to be hard to read .5 ohms on.
And it sounds like your meter is off some if you are reading .4 to .6 when touching the leads together, that should be a 0 reading.
.5 ohms is very close to a dead short.
Some cheap meters just show 0 ohm's or dead short when testing glow plugs.
An analog meter with a needle scale, is going to be hard to read .5 ohms on.
And it sounds like your meter is off some if you are reading .4 to .6 when touching the leads together, that should be a 0 reading.
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Elder User
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From: Morgantown, WV
Yes, it is about a $20 digital multimeter that I either got from Wal-Mart or Sears, I can't remember. It has always worked fine before, I thought? I guess it only works good on stuff like volts, but maybe it doesn't pick up sensitive stuff like low value OHM's?
Maybe I will go out today and buy a nice digital multimeter from Sears.
Well, I tried my test light again on the GP's, and the light still doesn't light up.
Maybe I will go out today and buy a nice digital multimeter from Sears.
Well, I tried my test light again on the GP's, and the light still doesn't light up.
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Elder User
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From: Morgantown, WV
Hey Dave. I just bought a Craftsmen Stage III Digital multimeter for around $70, so this one is much nicer. However, I tested the leads again, and when I set the switch to OHM's and touch the leads together, I am still getting around 0.3 - 0.5 ohm's on the screen. Occasionally I get 0.1 ohm's on the screen but I have to hold it very, very steady. Am I doing something wrong?
Post Fiend
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From: Faibanks Ak.
My snapon meter dissapeared and I don't remember who I loaned my simpson to so I bought an off brand at the auto parts that was supposed to be pretty good and it still is not good enough to test the gp's even the new ones read bad with it.
