Glow Plug Testing IN block

nikojo

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Illinois
Can you test glow plug while still in block?

I understand they should test between 1.5 and 5 Ohms with one probe on the connector tip and the other probe on the body at the threads.

I have not read whether it is ok to test them while in the block and just test off the hex portion of the body while it is screwed into the block.

If this can't be done this way I'd like to understand why.

Thanks for any insight.
 

Retiredwarhorses

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Can you test glow plug while still in block?

I understand they should test between 1.5 and 5 Ohms with one probe on the connector tip and the other probe on the body at the threads.

I have not read whether it is ok to test them while in the block and just test off the hex portion of the body while it is screwed into the block.

If this can't be done this way I'd like to understand why.

Thanks for any insight.
yes, they don’t need to come out to be tested, just use a good source ground…
 

Milcommoguy

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Rosamond, CA
Can you test glow plug while still in block?

I understand they should test between 1.5 and 5 Ohms with one probe on the connector tip and the other probe on the body at the threads.

I have not read whether it is ok to test them while in the block and just test off the hex portion of the body while it is screwed into the block.

If this can't be done this way I'd like to understand why.

Thanks for any insight.
See the video above. Gets the point across. Stay tuned............

If one is confident with their multi-meter... Yes to your question. Test your meter and leads first to verify proper operation. The resistance is very low in the range you state. Don't get worried being a ohm or two trying to match values. In the range and good to go. Basically, test is a GO-NO GO. Greater that 5 ohms, book says pull-um.

The harder part is fumbling around trying to hold the leads while standing on your head, looking to make the connection and read the meter, LOL.

Good strong alligator style clip leads or adapter... one to any clean engine ground and other, electrical tip of plug in question. (Hex part OK for ground, more fumbling)

Nice probe set or make some up with clips.
probe.jpg allagor.jpg NOT ONE OF THESE download (1).jpg

AND my cheap advice. for today... good to have a couple of these too for testing, bypassing, hooking something up, lighting something up, LOL

Handy test wires
test wire.jpg

The really hard part is getting the swollen ones out. Tip... Check the new one's going back in, just to be sure. A little anti-seize on the threads, good too. Check for nice and tight electrical contact on the tip under the boot.

Watch out for crap, cheap, knock-off plugs. Figure ten bucks a plug for USA. Less that that, with the money saved... run to the drug store and get a bottle of Tylenol extra strength. 💊💊💊

Now that winter is here, hard starting HumV's can be a problematic do to many issues. Started and ran great all summer and now... hard starts to won't start, smokes like a chimney till warmed up... just could be glow plugs, start box, fuel and the list goes on.
truck.jpg Time to PM systems.

Saturday morning car-toons. download (2).jpg CAMO
 
Last edited:

spankybear

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WA
just use a test light. Put the clip on any positive source and touch the pointy end to the tip of the glow plug. Tip meaning there the wire/connector goes. You also have to disconnect the wire. if it lights the test light you have a good glow plug.

<------------ An electronic tech at a major aerospace company. Just keep it simple!
 

nikojo

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Location
Illinois
Thank you everyone for the help. So funny I haven't read anywhere how these can be tested in their place. Seems to me this would save a lot of trouble LOL.
 

Milcommoguy

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Thank you everyone for the help. So funny I haven't read anywhere how these can be tested in their place. Seems to me this would save a lot of trouble LOL.
My thread from a couple of years ago... Goes hand in hand with easy and simple and CHEAP and stated above by spankybear and here it is......

> Lots of new... well old Hmmwv sales and ALL the problems (FUN) that goes with them.

Electrical issues can be a bit to chase down. Can't see them little excited electron running around. Your excited too, with a new and NOW DEAD HumV in the driveway.

To help one see them electrons and the parts energizing or not, I present this simple tester.

There's no need to stand around scratching your head and second guessing those pesky electrons and then getting sideways with fuel and pumps and filters and injectors and schrader valves on tires.

Eliminate the easy stuff with a GO-NO GO light. Good to have in your fix kit too.

Easy and simple to build. Need a light, socket for light, 9 + feet of wire (16 ga), couple of roach clips (alligator) and tape, (shrink sleeve optional). Parts right out of the junk box and a little time. See the pictures and fill in the blanks.

020.JPG
Socket, contact shell and pin from old tail light.

019.JPG
A 28 volt bulb, some wire and roach clips Ah alligator. The big red one is for Kurt. Just kidding.

023.JPG
The easy build, solder, splice, shrink sleeve, but no hot glue.

Now that you have it built, double check. Then the first test across the batteries. Bright light...Ya got it right.

Important note: Humv is a strong 💪truck... So you NEED strong batteries (both of them) and GOOD connections (all of them) to start with. (no PUN here)

Now jump ahead of the class and start answering those questions??

Do I have power to the ??? IP, glow plugs, starter, lights, heater, valve stems? Are the glow plugs in circuit or blown open. Once you get the hang of it (remember simple and easy) at home or on the trail, no more guessing.

No alligators were hurt in the building of this handy tester, CAMO
 

nikojo

Active member
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28
Location
Illinois
Just to close the loop on this.......I was able to test the plugs while 'in' the block. All of them were bad. Only two came out easily.

I bought the plug extractor but had to 'grind' it open a bit as my glow plugs were cheap chinese aftermarket. When you compare them to legit plugs you can clearly see the difference. Regular extractor will NOT fit only these plugs.

This did give me opportunity to apply proper antiseize on threads and dielectric on connectors.

Also had switched out the control box to the camotek.

I held my breath at first start but it didn't even hesitate......it was awesome. It's already cold here in Chicago low to mid 30's. Barely any white smoke clears quickly. It has never started so well.
 
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