Glow Plug Switch: MOD /with pics

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Oct 26, 2011 | 01:07 PM

#16

Talyn

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Joined: Oct 2003

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From: Ashland City, TN

Quote:

Originally Posted by madpogue

A regular latching toggle switch, in series with the PCM wire, would do the same thing, without requiring holding it. Turn it on, wait (buckle up), start the truck, turn it off. If you forget to turn it off, the PCM turns it off anyway.

Gotta wonder, too, if it's really cost-effective. The PCM leaves the glow plugs on to make for a hotter combustion during the first seconds/minutes of engine run. It'd be about impossible to measure, but I wonder if, without the GPs, it burns more fuel during those first moments, and esp. if you use a Stancor relay and Beru/Motorcraft plugs, how much their life is really shortened by the PCM-programmed run.

The PCM will turn them on no matter what, so you shorten the life that way.

but it does assist during warm ups on cold start with combustion.
but for 2 mins max.
so...
Your not loosing a lot.
You'll just waste more fuel after you turn the GP's off till its warmer.

Oct 26, 2011 | 02:03 PM

#17

madpogue

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Joined: Oct 2003

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From: Madison, WI

Quote:

Originally Posted by Talyn

The PCM will turn them on no matter what, so you shorten the life that way.

But by how much? Given a full set costs < $100, and the Stancor relay could last pretty-much forever, how much are you saving, versus how much extra fuel are you using by not running them? Probably impossible to calculate, but whichever way it swings, the net probably amounts to no more than a few tens of dollars per year.

Oct 26, 2011 | 02:04 PM

#18

richdawg

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Fleet Mechanic

Joined: Oct 2006

Posts: 1,386

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From: Spokane, WA

KISS: You guys are giving me a head ache!! All this stuff I didn't even think much about. Interesting though.

Oct 27, 2011 | 12:09 AM

#19

madpogue

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Joined: Oct 2003

Posts: 8,476

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From: Madison, WI

^^^^ +1; and IMHO, the best "S" (simple) approach is to have a heavy-duty relay like a Stancor, known good quality GPs like Beru / Motorcraft, and call it a day.