New Glow Plug Time...

mohavewolfpup

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Looks like the glow plugs are finally taking a dump in my truck. Anyone have leads on the good ones for a 6.9 diesel? Rockauto usually has the best pricing, but just want to check before saving up and ordering from there. Hoping for just the stock setup for now (new plugs/controller) as the truck is always needed to be working
 

austin92

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Everyone here always says to absolutely avoid autolites and only run motorcraft zd9's


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Macrobb

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For a 6.9, it's zd-1a.

That being said, you might want to think about upgrading to the 7.3 setup if you have an extra $100 to spend. The 6.9 relay can stick on, frying all your plugs. The 7.3 controller doesn't tend to do that.

Also, as long as your controller and 8 glow plugs are good, it /really/ works nicely. After getting my first IDI with a decent glow plug system a few months back, I'm totally a convert(compared to a manual push-button setup).
 

mohavewolfpup

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For a 6.9, it's zd-1a.

That being said, you might want to think about upgrading to the 7.3 setup if you have an extra $100 to spend. The 6.9 relay can stick on, frying all your plugs. The 7.3 controller doesn't tend to do that.

Also, as long as your controller and 8 glow plugs are good, it /really/ works nicely. After getting my first IDI with a decent glow plug system a few months back, I'm totally a convert(compared to a manual push-button setup).


I've seen in a few areas (just randomly online via searches) that a newer 6.9 controller (screws into the engine block) can greatly reduce frying the plugs? Should I add a new wheel well relay to the overhaul? As for the 7.3 retrofit, is that fairly easy or takes it down for a while? Trying to keep the system "turn key" if that makes sense since others use my vehicle who while aren't dumb with vehicles, shouldn't have to engage in a lengthy ritual with the glow plugs each time they need to use it
 

Shadetreemechanic

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Factoids for your decision, nothing scientific, just what happened to me.
One of my 7.3 controllers crapped out last month and took out all 8 motorcraft glowplugs with it. My only 6.9 controller crapped out about a year ago, but all the glowplugs in it are fine.
 

Macrobb

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As for the 7.3 retrofit, is that fairly easy or takes it down for a while? Trying to keep the system "turn key" if that makes sense since others use my vehicle who while aren't dumb with vehicles, shouldn't have to engage in a lengthy ritual with the glow plugs each time they need to use it
So, lets see:
A 7.3 controller has 5 wires to be connected:
1. Power input. You might need to run a heavy 6 ga wire from the battery/fender relay terminal to the back of the motor
2. Power output. This goes to your glow plugs. You will either need to make a harness, or modify one from, say, a 6.0 motor: https://www.amazon.com/APDTY-2004-2...&redirect=true&ref_=oh_aui_detailpage_o00_s00
All it is is a set of wires with connectors for each glow plug, connected to a post on the controller.
3. Ignition on - You just need a hot-in-start-and-run wire to power the controller/positive side of the relay; there should be one in the stock harness back there.
4. WTS light(Doesn't have to be connected, but if you want it, you'll need to connect)
5. Ground. Just a little black wire which can be connected to a nearby bolt; I used the one that holds the return rail 'clamp'.


If you get your wiring schematics out, it shouldn't be more than a couple of hours, if you are being slow about it.

late 6.9/7.3 style controller wiring:
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So, it looks like you can pull the red/green wire from the controller plug and use that for power.
WTS light may be more of a challenge: The 6.9 light wire is pulled high to power it, the 7.3 is grounded to power it.
You can either:
1. Pull the WTS light out of the dash, find the grounded terminal, and connect it to a power source instead.
2. Invert the signal using a relay under the hood. Here's a great explanation of how the common 'bosch style' relay works: http://6066gmcguy.com/BoschRelay.html
(basically, you'd use the 'ground to turn on circuit', but instead of using a switch, you connect that wire to the controller. The output, terminal 87, gets connected to the factory WTS light wire somewhere.



edit:
I will say that, /when working/, it's a very foolproof process: Key on, wait for WTS light to go out, crank and she fires right up. One dead glow plug, however, will make it much harder to start(more cranking), and with two dead it's even harder.
 

mohavewolfpup

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Thanks for the tips everyone, going to give it a once over tommorrow before ordering parts.

Maybe this helps ID it a little also. When I go to turn it over, the WTS light will come on, maybe staying on for 5-10? seconds. I hear a "thunk/thonk" it sounds like. I'll cycle it, the WTS won't turn on sometimes or it psuedo random comes on. On a warm day, it will start and now and then it turns on.

is the "thunk/thonk" sound what should be heard, or a sign of something going out? The engine always fired up when cold, but has been lazy lately. Worst issue was the lines, but I replaced all those and the olives shortly after I purchased it in 2013
 

Shadetreemechanic

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The noise you hear is the fender mounted relay turning off. Not possible to say whether your fender relay is getting intermittent signal from the controller, or whether its going bad. It is cheap and easy to get to though, so replacing it first would be relatively painless.
I don't know the history of your 6.9 controller, but at least some of them do not cycle when the engine is up to temp. Warm engines don't need glowplugs, but the later model ones cycle anyway to lower startup emissions.
 

Robm45497

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only run motorcraft I used to run autolites and would get less then 1 year or so before they would start losing them. I changed to motorcraft and they went for years.
 
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