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1994 E-350 7.3L IDI (NA) 4WD Quigley/AEA conversion (ex-ambulance)
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6 Posts
Discussion Starter #1
I think I understand how the system is SUPPOSED to work, but lack experience with the hardware!

My WTS light comes on for a few seconds, then goes out. (Normal)

But the voltmeter stays low, no clicks....the truck starts fine....but the ammeter is WAY up for a minute or so. I believe the glow plugs are staying on too long.

I have had alternator issues, and cringe at this excessive load. I must either fix the controller, or go manual (I am the only driver).

I don't understand the "zig-zag" resistor, do the glow plugs operate at a voltage other than 12v?

My PREFERENCE is to stay stock, but my PRIORITY is to be kind to the alternator!

Anybody?
 

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I don't know about the IDI diesels, but on '99 and newer trucks, the glow plugs will stay on for up to 2 minutes after key on. It depends on ambient temperature. Longer duration with lower temperature.
 

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1994 E-350 7.3L IDI (NA) 4WD Quigley/AEA conversion (ex-ambulance)
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6 Posts
Discussion Starter #3
The correct response to ignition "on is "Wait to Start" for 5 or 6 seconds, followed by a clicking sound, as the glow plugs relay cycles on and off. The duration of the clicking depends on the temperature. Cycling off prevents the glow plugs from melting. But I get no clicking whatsoever....the glow plugs draw current for almost a minute after startup. This cannot be good for the glow plugs, or the alternator!
 

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The relay times itself out by the resistance built up by the heating glow plugs. When the resistance builds up high enough, it shuts off, cycles back on when the resistance drops until everything is warm enough that it stops cycling. It sounds to me like the glow plug controller isn't reading resistance anymore, or the zigzag resistor isn't resisting anymore. I would look at the controller first.
 
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