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Discussion Starter #1
RE: 1995 f350 7.3L w/ Banks Kit

Started fine this morning, but at lunch, I knew right away I wasn't getting glow plugs. Looked under the hood at the glow plug solenoid, wiggled the wires and the post on the battery side was loose.. and with a little assistance pulled right out.
I thought "oh well, I'll short the two wires to energize the glow plugs to get home, then I'll get a new relay. I cleaned the two contacts w/ sandpaper and would hold them together w/ a pliers for about 15 seconds.. truck would cough a few times.. and I'd get a huge cloud of white smoke, but no start. Tried energizing the gps for 15 sec, then off for 15 and back on again for 15.. never got it to start.
Went back and looked at the solenoid (through the hole left by the missing post) and it looks like its stopped at the top. Now I'm thinking that's what happened, and it burned out all my glow plugs, and that's why when I short the contacts, it still won't start.
I've replaced the glowplugs in my 94 IDI 7.3l.. but that's a piece of cake. The glow plugs in the 95 are under the valve covers.
Is there any way to ck the glow plugs w/o pulling the valve covers? Is there something I'm overlooking? Thanks in advance for any assistance.
 

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The plugs are energized for over a minute when controlled by the PCM when trying to start. You can ohm test them through the valve cover plug. Do a search here to find a write up on t. Been a few years and I forget which pins and what ohms.
AaronSEIA
 

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Glow Plugs

The center pin is ground on plug harness IIRC outer pins are glow plugs and inner ones injectors.
 

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Discussion Starter #4 (Edited)
Thanks for your help. Pulled it home last night. Now I know what I'll be doing this weekend.

With my 94 IDI, I had read that about 15 seconds was as long as you'd want to energize them continuously w/o risking damage. In the PS F350.. are they energized continuously for 1 minute?.. or is it intermittent?
If I try again to start it by shorting the contacts, how long can I energize the glow plugs continuously?
I know I don't see any fluctuation on the dash voltmeter like I do on my 94 when the glow plugs go from energized to off (which I have wired for manual glow plug activation at the dash).
In any case, my WTS light went out after only about 15 seconds yesterday morning and it started right up, and it was colder than in the afternoon.
So I'm assuming it's the outer two contacts on each end that are to the glow plugs.
I'll get them tested. Thank you.
 

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I would think its like the IDI, just PCM controlled. Energized for @15 seconds and then cycled for the next two minutes as needed.
 

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Discussion Starter #6
Thanks.. but I learned differently. The gp's on the 95 pstroke energize for up to 2 minutes continuously. I thought it would be intermittent, but apparently not. That's why it wouldn't start when I shorted the contacts.. I was thinking I'd burn up the gp's if I went longer than 15 seconds, so I was holding them together that long, then disconnecting them and trying to start it.. whereas they would have been on all the way through cranking the key if the gpr was present. I should have known that because I always watch the voltmeter when I'm starting either of my diesels. Just didn't realize the 94 navistar gp's were that different that the 95 powerstroke.
Glow plugs tested at 1.3 to 2.4 ohms resistance. I left them in and put a MR-99 gpr in it that I got at autozone for $18.99, can't beat that.. got an extra for the glove box. Cleaned the contacts and it started right up first try. Since the gp's are a little weak, I'll just start waiting an extra 30 to 60 seconds when it's cold out.. will alleviate the white smoke problem somewhat.
 

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60 seconds is prob. more than you need, even with weak GPs. I'd try 'er at 30. The up-to-two-minute run time has nothing to do with starting the truck. And indeed, that continuous run is why a lot of cheap general-purpose relays are NOT appropriate for our trucks.

All those resistance measurements are high. 1.3 is marginal, but 2.4 is way high.
 

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Discussion Starter #8
Thanks, that information is very much appreciated.

I'll stick to 30 seconds, replace the gp's when warm weather gets here (don't have a heated garage), and I'll keep that extra gpr in the glove box.
 
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