Glow plug question

Coltonreece

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So when I bought the truck, the glow plugs were wired to a switch and only come on when I was holding this switch. Will this affect the way it runs after start up ?? Like so the glow plugs run while the engine is running ? Obviously only talking about the initial start up, up to 10 min
 

Nero

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Nope they are completely bypassed and only run when holding the button down.
 

IDIBOBS

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No once the truck is running the plugs should be off if everything is working correctly. My controller was bypassed also when I got it. I pulled it all out and rewired a new controller in and moved it to the passenger fender.
 

IDIBRONCO

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From the factory, both styles of controllers will after glow when it's cold outside. This means that the glow plugs are activated for a few, short cycles. The only effect that this has is to help put extra heat into the cylinders to get good combustion sooner. This only lasts for a few seconds after first starting the engine. You can mimic this with a manual control by activating the control. If it's in the teens, I might do a couple of 2-3 second after flows. In the single digits, I might do 3 or 4. Once the engine is running smoothly, I won't do any more after glows.
Once the after glows are over, with a factory controller, the glow plugs aren't activated any more. The only exception is the older 6.9 style controllers that had a bad habit of failing in the "on" position and burning out the glow plugs.
 

BeastMaster

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IDI BRONCO : I have noticed the same thing regarding manually goosing the GP after start, even though it doesn't get very cold here. I can *hear* the engine change tone as the engine warms up

I will point out I lost an alternator on my previous foray into glow plug relay that malfunctioned stuck ON. I suspect that once the engine caught, the voltage regulator pegged the alternator rotor full bore on in its attempt to hold the battery rail at 13.8 volts or so, but the alternator is rated 130 amps or so...and my glow plugs are drawing 25 amps each with the battery rail at 10 volts ( loaded with 200 amps - eight plugs ). So something had to give. No sooner than I replaced the alternator, the new one quickly finished every one of the glow plugs. I don't know if the old alternator had burned out any. At that time, I wasn't aware I had this much woe heading my way.

Anyway, once discovering my GP relay had welded-shut contacts, I replaced the relay. A week passed and it failed the same way, and took out the glow plugs again. Thoroughly disgusted and fearful of some hidden fault to ground in the glow plug circuit, I thoroughly inspected the wiring and found nothing wrong. I assumed it a strong possibility the controller itself was causing the relays to fail. I had seen a similar relay driver fail when a power supply capacitor became old and it's internal resistance went up, causing the coil drive to oscillate, causing the contact to make erratic contact which caused the contacts to weld. So, I bought a brand new Motorcraft name-brand controller. A few days later, it did the exact same thing! Thank goodness I still had the wrench handy to disconnect the battery when I noted the voltmeter failing to show the voltage increase when the relay was supposed to.
disconnect the plugs. Yup, the contacts were welded shut, again.

At this point, I went all manual with the same industrial contactor relay Wes Texas puts in his kits.


That was about three years ago.

No issues since.

During the summer in Southern California, i don't use my glow plugs, however, in the Winter, a few seconds pre-start glow saves a lot of work for the starter motor. I only need to use the plugs when the engine is cold. If the engine is still warm to the touch ( like it hasn't been down for over two to three hours ) , it will start right back up whether I glow or not.

I recently experienced a starter motor fail in such a manner where it gave a weak start and drew a *lot* of current.

It mimicked a bad battery or ground connection, as the voltage on the battery rail did not drop as much as expected. Turns out I had to run glow and starter simultaneously to get it started...really sluggish. The connections to it, and grounds, were sound. Electrical energy was going in, but not all that much mechanical energy coming out. My guess was maybe a shorted turn?

Oh, incidentally, I did remove the serpentine belt for the test start as I wanted to eliminate mechanical drag problems such as A/C compressor clutch malfunction, binding alternator bearings, binding tensioner bearings, etc. from consideration.

I still don't know the starter fail mechanism in play...commutator wasn't undercut correctly? Shorted turns? I just did not get the life from the starter motor I was expecting...I only got two years or so...I was expecting more like 30 or so.
 

IDIBRONCO

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During the summer in Southern California, i don't use my glow plugs, however, in the Winter, a few seconds pre-start glow saves a lot of work for the starter motor. I only need to use the plugs when the engine is cold. If the engine is still warm to the touch ( like it hasn't been down for over two to three hours ) , it will start right back up whether I glow or not.
I see the same thing here in northwest Kansas in the summer. If it's 95+, it will start easily without glow plugs. 90-95, it will start, but takes enough cranking with the starter that I use the glow plugs. Unless it's pretty cold, I usually only use the glow plugs to get the engine cold started in the winter. If, like you say, I let the truck sit for a few hours, then it wants glow plugs to start again, in the winter.
 

franklin2

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On the glowplug relays failing, it's also a common occurrence if you replace the starter relay on our diesels and gas engine also. The problem is they are simply cutting too many corners in the manufacturing these high current relays.

When you bring two pieces of metal together that have a large electrical potential between them, they will arc. The contacts need to resist the tendency to weld and stick together. In the old days they used silver coated contacts. These lasted a long time. But silver is expensive, they are using less and less of it and other good metals in the manufacture of these large relays. Some only last one or two cycles and they weld themselves together.
 
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BeastMaster

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On the glowplug relays failing, it's also a common occurrence if you replace the starter relay on our diesels and gas engine also. They problem is they are simply cutting too many corners in the manufacturing these high current relays.

I also suspected this was the cause, So I chose an industrial contactor from a completely different heritage.

I just had a starter motor fail too far sooner than expected. Seems like these things are planned to fail. I have a 40 year old washing machine ( Sears Kenmore Model 70 Direct Drive ) that still runs just fine, although it's gone through two water pumps, four sets of agitator dogs, and a drive clutch, all of which were designed for easy replacement, and are still available.

But I have had the damnedest failures on brand new replacement parts for my E350 IDI...like tach sensors...it's just a magnet, a pole piece, and small spool of copper wire...and the thing fails open a month after installation?

I am looking into ways of deriving a tach signal from the alternator ( technically an analog phase-locked loop frequency synthesizer which outputs a frequency M/N times the input frequency, both M and N being integers between 1 and 255 - choose closest M and N to get desired pulses / revolution ).

Anyone seen such a thing? I hate the idea of replacing the simplicity of a coil of wire and a magnet with the Rube Goldberg contraption I have in mind. I Don't like putting modern electronics, high currents, inductors, and hard-contact switches anywhere near each other...especially all four in the same box!
 

mf7lakes

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( technically an analog phase-locked loop frequency synthesizer which outputs a frequency M/N times the input frequency, both M and N being integers between 1 and 255 - choose closest M and N to get desired pulses / revolution)

I saw one once -- but it was on a delorean and it accelerated to 88 mph -- then it disappeared
 

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