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  1. #1
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    Perplexing EZ start glow plug issue

    So I've read through the forums about glow plug issues with EZ start and I know that a lot of people don't like them and they end up ditching the glow plug ignitor wire for a regular glow igniter... I've been doing that and it's fine, however I did rig up my T-Maxx 3.3 with a remote start that I can start from the transmitter, so I really want to get this to work.

    I've checked all the most common problems and I'm pretty mechanically and electrically inclined, but this one has me stumped. The EZ start wire is giving me about 1.4v, same as my glow igniter, but even doing the usual glow plug test while touching the plug threads directly to the ground wire doesn't light it up.

    I also borrowed a friend's EZ start wand that I know works because it started his truck right up using the EZ start wire as intended, and still didn't work on mine, so it's not the wand. It's not the plug, and it doesn't seem to be the wiring because I'm able to get voltage readings through the circuit. Even tried a different wiring harness, same results...

    I'm perplexed. I recorded a video to show all of the above in action. Check it out here: https://youtu.be/CpRc6zk0TWA

  2. #2
    RC Champion grizzly03's Avatar
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    If you unhook the EZ-start motor (red/black wires) will the glow plug work then?
    It's possible to not be getting the required amps.

  3. #3
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    That is the only other possibility I thought of right after I posted this, and I was just going to check the amp draw across the glow plug with my multimeter, but haven't had a chance to yet. But disconnecting the motor and then trying it is another good way to check qualitatively instead of quantitatively. As far as measuring the amps across the glow plug, I was trying to figure out what it's supposed to draw and I've heard everything between 1 amp and 4 amps. The most plausible value was a table I found for OC plugs, and guessing from a somewhat comparable plug, it should be somewhere around 2 to 3 amps. I'll check both of those things and let you know.

  4. #4
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    Well, I think you're right on. My regular glow igniter puts out about 7-8 amps, and I'm only getting 1.4 mA from glow wire to ground...

    With motor disconnected it still doesn't glow and only puts out 1.4 mA. That would make me think it's a bad wand, but I just tried my friends wand 10 seconds after he started his truck with it and it didn't work. His wand still worked on his truck after that though. The only thing I didn't try is my wand on his truck, because mine's attached to my chassis. I don't want to waste $15 buying a new wand if it's not the problem, but it's starting to sound like it is so I might just do it.

  5. #5
    RC Champion grizzly03's Avatar
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    Another possibility is the blue wire. Check to make sure there are no cuts or exposed wire anywhere.

  6. #6
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    I’m confused. You said you’re leaning towards it being a bad wand, but you said your friend’s wand didn’t work either. I’d think that rules that out. I’d lean towards the blue wire being damaged somehow and having high resistance but you said you tried a different wire harness. I assume that was a different blue wire as well, so that would rule that out unless both were damaged. Could there be something in the remote start you rigged up that’s drawing power away? Be interested to see what you find.

    Edit: What about your 6 cell battery? Did you use that battery when you tried your friend’s wand? Certainly sounds like it’s turning the starter motor fine, but maybe something in the connection there that’s keeping it from supplying enough amps.

    Also also wik wik edit: Ground wire connection solid?
    Last edited by cjtamu-redux; 08-12-2020 at 10:13 PM.

  7. #7
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    Quote Originally Posted by cjtamu-redux View Post
    Iím confused. You said youíre leaning towards it being a bad wand, but you said your friendís wand didnít work either. Iíd think that rules that out. Iíd lean towards the blue wire being damaged somehow and having high resistance but you said you tried a different wire harness. I assume that was a different blue wire as well, so that would rule that out unless both were damaged. Could there be something in the remote start you rigged up thatís drawing power away? Be interested to see what you find.

    Edit: What about your 6 cell battery? Did you use that battery when you tried your friendís wand? Certainly sounds like itís turning the starter motor fine, but maybe something in the connection there thatís keeping it from supplying enough amps.

    Also also wik wik edit: Ground wire connection solid?
    I'm confused too. I only had a few minutes to test things with his wand, so couldn't thoroughly investigate with multimeter to see what kind of amps his was putting out. Basically it started his truck, didn't start mine, then started his again. To answer your question, blue wire is intact, solid soldered connections with heat shrink, no exposed wire. Ground is likewise solid and i even changed the mounting location to the engine to 3 different spots, ensuring all contacts were clean.

    A little note that I left out from before because I didn't think it would matter since I was getting the correct voltage (didn't think about amp draw from the plug being that significant at the time, but I guess it is), is that my wand was originally putting out 4-5v across the glow plug circuit. Didn't realize that was too high until I did more research and found that the optimal voltage should be 1.2-1.5v, but it wasnt frying the plugs probably because it wasn't putting out enough amps, but I didn't think of that at the time. That's another reason I suspect the wand is bad, though i still can't explain why my friendís new working wand didnít fire it up.

    So to fix the high voltage output, I cannibalized a potentiometer from an old servo and rigged it along the blue wire as a variable resistor, so I could adjust the output voltage by turning the servo arm to bring the voltage down to 1.4v. When that didn't work, I posted this thread because I was stumped and at the end of my limited knowledge. I think you guys put me on the right track by looking at the amps, which I had neglected because I assumed it would be minimal to light up a little filament. I'm going to just buy another wand today and ditch that potentiometer and see if that's the issue.

  8. #8
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    Almost sounds like whatever in the wand controls the voltage and amperage for the glow plug wire is kaput. Yeah, voltage is low for a glow igniter because it's only a single cell, so 1.2-1.5 V depending on whether it's a rechargeable cell or alkaline. I don't remember seeing you post it, but might try your friend's wand on a spare glow plug. See if it heats up when you hit the EZ Start button.

  9. #9
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    Yeah, that's the kind of testing I wanted to do with his wand, but didn't have time. I picked up this T-Maxx used for $150 with a treasure trove of additional tools and parts (probably worth that much by themselves), along with 2 pretty beat up wands missing the back covers. I pulled the board out of one and found the board itself had a small crack, so that was no good. Wouldn't hurt to have a new one anyway.

  10. #10
    RC Champion grizzly03's Avatar
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    Be sure to use the yellow and blue wire for the glow plug. The red and black for the starter. Both are separate circuits in the wand. If you try the blue wire with the black you get a lower voltage.

    Here is what I get for voltages on my EZ-start wand. Hope it helps.



    The wand and potentiometer is probably the issue. If you tried your friends wand on your wiring with the potentiometer, it would go even lower than the 1.5v-2.0v it is putting out. That's the reason your friends wand wouldn't work on your truck.

  11. #11
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    Yes, for sure using blue with yellow ground. Like I said, I know enough about electronics and circuits to be dangerous... I've had 2 semesters of college physics and radiation and nuclear physics training for work (had to take and pass a national nuclear physics board exam, but that was years ago). So while not directly applicable, there is enough background knowledge for me to pick this stuff up and learn quickly thanks to folks like you pointing me in the right direction.

    But I think you're absolutely right about the potentiometer further lowering the voltage/current of his wand. That would certainly explain it. Picking up a new wand today and I'll let you know.

  12. #12
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    Quote Originally Posted by GoleeMD View Post
    Yes, for sure using blue with yellow ground. Like I said, I know enough about electronics and circuits to be dangerous... I've had 2 semesters of college physics and radiation and nuclear physics training for work (had to take and pass a national nuclear physics board exam, but that was years ago). So while not directly applicable, there is enough background knowledge for me to pick this stuff up and learn quickly thanks to folks like you pointing me in the right direction.

    But I think you're absolutely right about the potentiometer further lowering the voltage/current of his wand. That would certainly explain it. Picking up a new wand today and I'll let you know.
    Hi, check out my thread from a few weeks ago. I had a very similar issue except mine melted 3 glow plugs. The glow plug light wouldnít light up on my wand and I was getting various readings from my voltmeter on the glow plug part of the wand. On the second plug I got it to start using my other wand. Ran a tank and it wouldnít restart. Other plugs melted. To be safe I just got a new wand. Also I set the tune back to factory. It sounded crazy to me since the tune shouldnít have anything to do with the starter but I think it was too lean (I last tuned in 65 degree F weather and now itís 100) and the glow plug didnít have enough fuel to burn so it died? Just a theory, not sure if this is the actual reason but try it out. It could also be too much power being sent to the plug. That was what I originally thought since the plugs looked melted. Also take a look at your glow plug and test it. If it doesnít work check to see if the coil part looks normal (similar to spring) or if it looks like it fused itself together. Itíll look like a blob of metal stuck in the middle of the coil.

    TLDR: Try resetting tune. Check if glow plug is still lighting (you can use a working ez start and ground it to the engine head or use glow igniter). If not check to see if the plug looks melted. Hopefully it fixes it. I also got a new wand to be safe since I didnít want to waste more $ burning plugs. Lol I still donít understand how it happened weeks later but hopefully it works for you.

  13. #13
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    Unlikely tune had anything to do with your melted plugs. It doesn’t affect the starter, just maybe how long you have to hit the button to get it to start. And as a general rule, if it’s 35 degrees warmer (and I assume more humid) than last time it was tuned the engine would be a little richer, not leaner. I’m betting you had an electrical issue as well.

  14. #14
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    So it was definitely the wand. Hooked up the new one and removed the potentiometer and was getting 1.6v and 6 amps on the glow plug circuit. Bad boy fired right up! Check it out: https://youtu.be/mZr1NXibaAM

  15. #15
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    Glad you got it up and running with your remote! Keep it up!

    Have fun!
    Creativity is intelligence having fun. -Einstein

  16. #16
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    Sweet. Glad you got it.

  17. #17
    RC Champion grizzly03's Avatar
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    It sure did start quick. Awesome!

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