Same Newb-Different question! Ignition Switch - Diesel Forum - TheDieselStop.com
7.3L IDI Diesels (Not Power Strokes) Technical discussion of topics related to vehicles powered by the 7.3 Liter In-Direct Injection Navistar engines.

 15Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 73 (permalink) Old 12-15-2017, 04:35 PM Thread Starter
Member
 
jmshawii's Avatar
 
Join Date: Dec 2017
Location: Escanaba, MI, 49829
Posts: 52
My Photos: (0)
Feedback Score: 0 reviews
Same Newb-Different question! Ignition Switch

So, I am not sure if this kind of question is really supposed to go on here, as it is admittedly not "7.3 Diesel Engine-Related," but is a peripheral problem. If it is not considered "on-topic," my apologies, and no offense taken if taken down. Once again, I did some searches, but when there are this many little detail words in the problem, hard to tell which ones will find a proper answer for you. I am humbly submitting this question based upon the seemingly high level of general automotive knowledge on this forum.

So, the vehicle in questions is a 1988 International Harvester S1654 with an IDI 7.3. Retired Uhaul Box Truck. It has had the rear box removed and a car-hauling flatbed built onto it. I got it dirt cheap because it is a beat-up, dirty old oddball (pics will be posted when I reach enough posts to be allowed to post one!), but when I went to look at it it seemed to run so strong that I bought it despite many shortcomings that would cause concern to a sane person. So I drove it home over about 100 miles, and it still ran great. And, believe it or not got about 14 MPG! So, for the past couple of days I have been going through it and trying to mend some things (see my first post on here, dealing with the usual glow plug circuit questions!).

This AM, having "hot-wired" a glow plug circuit before, I thought I would just do that to see if the glow plugs were working, and if it would then fire up without the ceremonial offering of ether/starter fluid to the Diesel gods. I had looked at and watched a couple of videos on these pages, as well as on YouTube, and thought I knew a technique to use. With the 4 posts atop the glow plug relay, which I had tested to see which carried electric under what key position, and having seen one video that said the two different key-activated posts powered the 2 different banks of glow plugs, I simply ran a wire from each of these posts to one of the glow plugs on each bank. I figured if these glow plugs were wired in-line, which was my suspicion, if a wire went to one, it would travel down the line to the other 4 on that side. With temperatures in the 50's, I figured that even if it didn't power all the glow plugs, even one warming up on each bank might inspire a start. So, I wired everything up, made sure neither of my "jumper wires" were contacting anything else, and got in to turn the key.

Turned the key to on: normal racket from buzzers, dash lights on, WTS/GLOW PLUG light on, etc. Went to turn the key to the START position, and it all went DEAD! No more buzzers or noise, no dash lights, and no starter turn. There was no "pop", "click," "snap," "crack," flash of light, etc. Just NOTHING! I got out and checked to see if one of the wires had contacted something and caused a short and it appeared not. After repeatedly turning the key on, I never got any power back to the key/dash again.

So, I spent a couple hours trying different things, trouble-shooting by searching this site as well as several other sites and search engines, etc. I still have no power to the key switch (it would appear), no dash lights, no warning beeps or buzzers, etc, with the key on. I checked and did have juice making it to the glow plug relay (BIG post on the relay), as well as the main cable to the battery was still carrying juice. The headlights come on. The batteries are brand new and have been working well, and I run it often for long periods while working on it to make sure it is staying charged. All gauges have seemed to work, including the voltmeter, and it has always shown proper function. I DID unhook the cables from the battery and clean them, though they were just cleaned and put on about 3 weeks ago when the new batteries were installed. I also unbolted and cleaned and reattached the negative cable to the frame to be safe. But the fact that there is juice to the battery, the glow plug relay and the headlights work makes me think this was never the problem regardless. I am thinking the ignition switch, but read several posts that warned that the ignition switch was often NOT the culprit, even after people THOUGHT that had to be the problem.

So, my questions is two-fold, if not more. Does it sound like an ignition switch issue? If not, please talk me through it, because I love eventually understanding things!

The other question is: Was there something in my attempt to "hot wire" or "jump" the glow plugs responsible for this event? If so, is it likely I damaged something else in doing this? Does this ancient piece of equipment likely have an ECM type of compnent even-in some posts for some vehicles, I have seen people saying this was the cause or possible cause of their problem)? (Those 3 questions are obviously only one "fold," thus, me saying it was a two-fold question)

And, yet another question, I guess-what would YOU do next to rectify or try to check this issue?

My current plan is to go buy another key switch for it (old fashioned switch and key in one-mounted in the dash, not a key switch in column and actual switch down at end of column) and try that next.

Info of note, I am traveling, have more tools at home, and do not wish to buy a new multi-meter here only for this problem. I have a NICE one at home, which is limiting in this instance for sure, but at some point, even if it means MORE manual tests, shouldn't I be able to diagnose this without it?

THANKS for any info and advice, and thanks for being here!

Last edited by jmshawii; 12-15-2017 at 04:43 PM. Reason: Found errors/further explanation
jmshawii is offline  
Sponsored Links
Advertisement
 
post #2 of 73 (permalink) Old 12-15-2017, 05:55 PM
Senior Member
 
Join Date: Nov 2008
Location: Salina, Kansas
Posts: 1,537
My Photos: (0)
Feedback Score: 0 reviews
On the fender well, passenger side, the starter relay has two fusible links. One goes to the glow plug relay/controller, and the other goes to the charging system. Pull on those fusible links. the wire in them sometimes burns, and leaves the insullation looking just fine. I don't remember if the starting system is wired in with the fusible link, or not. On top of the steering column, about where the dash board ends is where the ignition switch is located, it isn't hard to remove, and use a small screwdriver, or allen wrench to activate it, just in case the "umbrella" that used to break regularly did just that. Usually turns on the switch, but doesn't have enough travel to make it to the starter circuit. The many times it broke for me, there wasn't any indication that it broke, just lost the starter circuit. You can also jump the relay from the primary (small) wire to the batt. side of the relay, MAKE SURE the transmission is in neutral or park. The relay on the fender well energises the starter solenoid when activated by the start position of the ignition switch

1993 F-350 crew cab non-turbo 5 speed transmission
35 years a mechanic on large stationary engines natural gas and diesel fired, and other industrial equipment.
oldrebuiltdodge is offline  
post #3 of 73 (permalink) Old 12-15-2017, 07:49 PM
Senior Member
 
Join Date: Nov 2008
Location: Madison, WI
Posts: 2,373
My Photos: (0)
Feedback Score: 1 reviews
Do we know that an IH truck has a similar starter circuit? That's a pretty Ford-specific design.
madpogue is offline  
Sponsored Links
Advertisement
 
post #4 of 73 (permalink) Old 12-15-2017, 09:01 PM
Senior Member
 
Join Date: Nov 2008
Location: Salina, Kansas
Posts: 1,537
My Photos: (0)
Feedback Score: 0 reviews
Good question. International has always mimiked everyone else, so there is no telling what they did. I would still be willing to bet that he poped a fuse, or fusible link. The old '65 IH that my father had was exactly the same thing as the Ford truck has now. Don't know if they still do though.

1993 F-350 crew cab non-turbo 5 speed transmission
35 years a mechanic on large stationary engines natural gas and diesel fired, and other industrial equipment.
oldrebuiltdodge is offline  
post #5 of 73 (permalink) Old 12-16-2017, 06:56 AM Thread Starter
Member
 
jmshawii's Avatar
 
Join Date: Dec 2017
Location: Escanaba, MI, 49829
Posts: 52
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by oldrebuiltdodge View Post
Good question. International has always mimiked everyone else, so there is no telling what they did. I would still be willing to bet that he poped a fuse, or fusible link. The old '65 IH that my father had was exactly the same thing as the Ford truck has now. Don't know if they still do though.
Thanks for the info and advice. Yes, I also wondered how similar my set-up would be when you were describing the Ford. This is a "big" truck-bigger than a pick-up. More like a GMC "Top Kick," with a tilt forward front end, so nothing is mounted on the inner fender area. I will try to look around and trace and see if I can't find some fusible links.

As for the key switch, I guess I didn't describe it very well either. It is an OLD style-no rods running down the steering column to the actual "switch," but the old key that goes straight into the vertical dash that faces you on the left side of the steering wheel. The key goes into the key cylinder, which is mounted into a round cylindrical switch that has about 10-11 blade connectors on the back, 8-9 of which have "blades" connecting to them. Very similar, to what a lot of my OLD (60's era Scouts, Pickups, Travelalls) IH's have had in them. So this is the switch I was thinking may be bad. However, I THINK there is supposed to be a live wire that is always carrying current to this switch, and when testing with a testing light, I could find NO juice to the switch. Thus, I am kind of in agreement that it likely ISN'T the switch, but is more likely something BEFORE the switch. I guess I now have to go trace that backwards as well as possible too. That is difficult, as the firewall connectors and fuse box are WAY up under the dash, with MANY wires running around back there, so trying to follow individual wires is somewhat difficult!

I am guessing that the "hot wire" to the key/ignition/start switch is the thickest wire running to the switch. It is black on this switch, tied into a four or 6 prong connector. There is also a red wire, but I THINK it is the power OUT wire, not the power in, because I was testing it before the power outage and it seemed to be key-controlled, but I could be wrong on this.

Hope this explains a little more of what I am working with.

Thanks!
jmshawii is offline  
post #6 of 73 (permalink) Old 12-16-2017, 10:55 AM
Senior Member
 
Join Date: Mar 2001
Location: Cody, Wy
Posts: 11,810
My Photos: (27)
Feedback Score: 0 reviews
You're just going to have to start tracing back with a test light to find where you're losing current. I'm well acquainted with IH trucks, worked on all sizes from semi tractors on down. Wonderful thing about them, most all wires are well color coded----BLACK. They DO have coded numbers on the wires but it's generally impossible to see the tiny numbers, especially under the dash. Can't be of help regarding the glow plug circuit because I never worked on any of the series with a 7.3 IDI engine.

Heavy truck and diesel mechanic (thankfully retired after 30+ yrs)
'91 F-250 SC 4X4, 5spd. ATS Turbo, 3:55 diff.
LMJD is offline  
post #7 of 73 (permalink) Old 12-16-2017, 12:14 PM
Senior Member
 
Steve83's Avatar
 
Join Date: Jan 2006
Location: Memphis, TN 38133, USA, Earth, Milky Way
Posts: 1,689
My Photos: (0)
Feedback Score: 0 reviews
You can post pics right now using the instructions at this link:
http://www.supermotors.net/forums/th...-and-or-videos

Stringing jumper wires around is risky, and you might have burned a fuse or fusible link that feeds the ig.sw. - not the switch itself. Try to find your truck on this site (you don't have to use a real e-mail to get access):
BBB Industries - TSB's & Wiring Diagrams
Be sure to click "WIRING DIAGRAMS" before entering the truck info. If you find your truck, post the data you entered so we can look up the same diagrams you found.

A cheap digital multimeter ($10-30) &/or a 12V test light ($3-15) are enough to diagnose this problem. This diagram explains fusible link wires, and how to repair them:


https://www.supermotors.net/registry/media/830776


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Steve83; 12-16-2017 at 12:18 PM.
Steve83 is offline  
post #8 of 73 (permalink) Old 12-16-2017, 02:38 PM Thread Starter
Member
 
jmshawii's Avatar
 
Join Date: Dec 2017
Location: Escanaba, MI, 49829
Posts: 52
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by Steve83 View Post
You can post pics right now using the instructions at this link:
How do I post pictures, sounds, and or videos? | SuperMotors.net Forums | SuperMotors.net

Stringing jumper wires around is risky, and you might have burned a fuse or fusible link that feeds the ig.sw. - not the switch itself. Try to find your truck on this site (you don't have to use a real e-mail to get access):
BBB Industries - TSB's & Wiring Diagrams
Be sure to click "WIRING DIAGRAMS" before entering the truck info. If you find your truck, post the data you entered so we can look up the same diagrams you found.


https://www.supermotors.net/registry/media/830776
Well, as you said I did TRY to find my truck on that site... But they do not list International, so that was a bust! Thanks for the try, though! And thanks for the fusible link page. I KNOW what one is, and understand how they work and why they are needed, but I can't FIND any so far in my truck! Unless I simply am not recognizing them. What I am used to-again, in my OLD jalopies, which is mostly what I work on, looks most like the one shown in the bottom left corner of the page you sent me-small, plastic cylinder with a fuse inside. Don't see any of these. There were some larger, black plastic cylinder connectors that I thought may have been an updated version, and they still may be, but upon disconnecting them, there was no fuse inside, just a "needle/pin" recessed into one end that goes into a recessed "tube" on the other end.

I did crawl underneath and follow the battery cable to the starter, where I have power to the terminal I should have power to (key off). I then followed the cable up to behind the engine, where it branched off to individual wires. One of these larger guage wires went to the GP Relay, and it was powered (constant-key off). I then followed the parts of the loom that went up to the firewall in front of the dash, which enters the cab through the fuse box. All wires are black, as the prior poster said. LOT of help there, IH!

I did find one larger gauge wire that was going to a post on the firewall, from which another wire/cable went a few inches to another post on a relay/selenoid looking piece. There WAS power to this post (key off), but none coming from the OTHER post on this piece (magnetic switch? I saw something on some wire diagram I found on-line called that... With an internal fused link maybe?). I had tried to get my tester into the little receptacles in the "plug" on the firewall side of the connector at the fuse box, to see if I couldn't find some source of constant live (even with key off) electric there, as I thought there should be. The wires are so tightly packed in there that I had a hard time, and I never did find any juice to those points/wires/terminals. I was sure there should be some there (there are 5 wires that leave the BIG, LIVE stud/terminal on the starter, and I figured at least ONE of them was a constant live wire going to the dash and possibly the key switch, but could find none.

So, happy as I was that I was able to trace many wires as far as I could, I still found nothing.

So, back to what I think should be a simple question that will help rule out the ignition switch as the main/only culprit behind this problem:

SHOULD there be a live wire feeding the key/ignition switch?

Thanks again to those who have been checking in and helping out! I'm headed back out to get back at it!

Last edited by jmshawii; 12-16-2017 at 02:43 PM. Reason: Typo
jmshawii is offline  
post #9 of 73 (permalink) Old 12-16-2017, 11:07 PM
Senior Member
 
Steve83's Avatar
 
Join Date: Jan 2006
Location: Memphis, TN 38133, USA, Earth, Milky Way
Posts: 1,689
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by jmshawii View Post
I KNOW what one is...small, plastic cylinder with a fuse inside.
Apparently not, because that's not what a fusible link wire is. READ that caption - a few times, if necessary.
Quote:
Originally Posted by jmshawii View Post
...a relay/selenoid looking piece.
This is where you posting pics would really help us help you.
Quote:
Originally Posted by jmshawii View Post
...I was able to trace many wires as far as I could, I still found nothing.
Then you're not starting in the right place: THE BATTERY. Put your meter's/test light's Black probe on the battery (-) post (NOT the terminal around the post), and the red probe on the battery (+) post, and you should get a reading. If not, the battery is dead. With that initial reading, move ONE probe to the terminal around the post - you should get the same reading. Then to the wire going into the terminal - again, the same reading is expected. Keep moving ONE physical component down the circuit at a time (with either probe, but move only ONE probe at a time, and only ONE component) until the reading changes. When it does, you just crossed over the fault.
Quote:
Originally Posted by jmshawii View Post
SHOULD there be a live wire feeding the key/ignition switch?
Of course - probably several.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Steve83 is offline  
post #10 of 73 (permalink) Old 12-17-2017, 08:08 AM
Senior Member
 
Join Date: Mar 2001
Location: Cody, Wy
Posts: 11,810
My Photos: (27)
Feedback Score: 0 reviews
Don't start at the battery wasting effort. Remove the ignition switch and look at the back of it. IIRC one of the terminals will say "ign" which will be your always hot one. Then work from it back. Also, most IH trucks have a small panel of circuit breakers, maybe above or around the glove box. One of them could be the problem.
oldrebuiltdodge likes this.

Heavy truck and diesel mechanic (thankfully retired after 30+ yrs)
'91 F-250 SC 4X4, 5spd. ATS Turbo, 3:55 diff.
LMJD is offline  
post #11 of 73 (permalink) Old 12-17-2017, 08:48 AM
Senior Member
 
chuckster57's Avatar
 
Join Date: Apr 2008
Location: Central Valley, Ca.
Posts: 17,604
My Photos: (7)
Feedback Score: 1 reviews
Quote:
Originally Posted by LMJD View Post
Don't start at the battery wasting effort. Remove the ignition switch and look at the back of it. IIRC one of the terminals will say "ign" which will be your always hot one. Then work from it back. Also, most IH trucks have a small panel of circuit breakers, maybe above or around the glove box. One of them could be the problem.
Right. When we trace 12V issues in an RV, we start at the place current is lost. If you start at the battery, the power probably branches off in several places.
LMJD and oldrebuiltdodge like this.

1994 F-350 7.3 IDI Turbo, crew cab, E4OD,4:10 L/S, LB, Dually
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

ATS Turbo upgrades: 3" DP with 3" exhaust Magnaflow XL muffler:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2012 Copper Canyon 273 FWRET w/2 slides, Air Lift 5000 bags
Pillar pod: Autometer C2 Series gauges: pyro,trans, boost, water, oil pressure
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Hypermax Cowl induction, K&N air filter, flex-a-lite 26K trans cooler with fan,Tekonsha prodigy
Train Horns:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


PM please not visitor message
chuckster57 is offline  
post #12 of 73 (permalink) Old 12-17-2017, 11:34 AM
Senior Member
 
Join Date: Mar 2001
Location: Cody, Wy
Posts: 11,810
My Photos: (27)
Feedback Score: 0 reviews
On a like note, only the opposite situation, when I first went to work in a truck shop a semi came in pulling a '53 trailer (like Walmart) with a short somewhere in the trailer lights. How do you find the short when all the wiring is basically enclosed in the van side? An old time mechanic took me under his wing, pulled out a hand held ammeter a bit like below only with a slot in the back you can lay over wires and it shows the amp draw. He had me hold the ammeter near the wire loom while he quickly flicked the trailer light wires which made the needle jump. Moving down the trailer side and suddenly no more jump, that showed where the short was. Bought one of those gauges next time the tool truck came by and still got it. Mucho handy!


Might be handy for you working on RV's, Chuckster57. If they still make them.

Heavy truck and diesel mechanic (thankfully retired after 30+ yrs)
'91 F-250 SC 4X4, 5spd. ATS Turbo, 3:55 diff.
LMJD is offline  
post #13 of 73 (permalink) Old 12-17-2017, 01:10 PM
Senior Member
 
Join Date: Nov 2008
Location: Salina, Kansas
Posts: 1,537
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by LMJD View Post
On a like note, only the opposite situation, when I first went to work in a truck shop a semi came in pulling a '53 trailer (like Walmart) with a short somewhere in the trailer lights. How do you find the short when all the wiring is basically enclosed in the van side? An old time mechanic took me under his wing, pulled out a hand held ammeter a bit like below only with a slot in the back you can lay over wires and it shows the amp draw. He had me hold the ammeter near the wire loom while he quickly flicked the trailer light wires which made the needle jump. Moving down the trailer side and suddenly no more jump, that showed where the short was. Bought one of those gauges next time the tool truck came by and still got it. Mucho handy!
https://www.amazon.com/Bosch-SP0F000...531093&sr=1-18
Might be handy for you working on RV's, Chuckster57. If they still make them.
They are handy, and the new digital ones won't react fast enough to show a blip like that. I think that amprobe still makes them, at least 10 years ago they did. That's when I replaced mine.

1993 F-350 crew cab non-turbo 5 speed transmission
35 years a mechanic on large stationary engines natural gas and diesel fired, and other industrial equipment.
oldrebuiltdodge is offline  
post #14 of 73 (permalink) Old 12-17-2017, 01:49 PM
Senior Member
 
Join Date: Mar 2001
Location: Cody, Wy
Posts: 11,810
My Photos: (27)
Feedback Score: 0 reviews
Thought mine was in my rollaway box but it's missing in action so I don't know what brand it is. I Googled and see they still make them:
https://www.autoelectricsupplies.co....84/category/88

It appears that one's made in England so it probably lasts about as long as it takes to get here.

Heavy truck and diesel mechanic (thankfully retired after 30+ yrs)
'91 F-250 SC 4X4, 5spd. ATS Turbo, 3:55 diff.

Last edited by LMJD; 12-17-2017 at 02:05 PM.
LMJD is offline  
post #15 of 73 (permalink) Old 12-17-2017, 02:23 PM
Lifetime Supporting Member
Lifetime Supporting Member
 
bugman's Avatar
 
Join Date: May 2002
Location: Gypsum, Co
Posts: 8,386
My Photos: (12)
Feedback Score: 1 reviews
Along the same lines as the amp meter showing where the short is located at we use a different method when I worked for a telcom finding shorts in overhead cables.

Once we had a short on the line we would place a tone onto the shorted wires. Then using a devise to listen to the tone we could follow it until the short. Once at the short the tone would stop and not follow the cable any further.

I believe that this is the same method that some of the short finders that are on the market for automotive troubleshooting now use. I'll have to do some searching and see what's out there.
LMJD likes this.

96 F250 PS XLT 4X4 long box, 5sp,4.10, manual hubs,pyro+boost guages, Dark Toumaline, add a leaf, Dale's TYMAR, and HX hose, downpipe, coolant filter, Luk clutch
bugman is online now  
Sponsored Links
Advertisement
 
Reply

  Diesel Forum - TheDieselStop.com > Ford Diesels > 7.3L IDI Diesels (Not Power Strokes)

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Diesel Forum - TheDieselStop.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome