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Discussion Starter #1
Hello!

I have been lurking around this forum the last few weeks trying to research all of the problems I have with this 1990 Ford F350 7.3 IDI-NA with 105k miles on it. I used a lot from previous posts, and I actually got the old girl to fire up and run pretty good yesterday!

I have a few things I think I want to get done before taking this truck on such a big trip, especially in the winter. Heading back to the Midwest from Carolina's for the rest of the crap I decided I needed to keep.

I’d like to get some more opinions on what the community thinks I should look into, get serviced if I can’t do it myself, before such a trip. I plan on driving it a few hundred miles on some weekend day just to road test it for the longer haul.

Things that I have done so far:
  • Replaced Mechanical Fuel Pump
  • Replaced fuel return lines, caps, o-rings. (Only rubber I did not replace is from back of barbed union joint to wherever that line goes back to my tank/tank selector valve)

Things I would like to do/fix:
  • Truck still just cranks and cranks in the morning. So I am either getting air in the system still, or it needs heat. Will fire right up and immediately idle with the smallest shot of ether.
  • Install newer style fuel filter - FRAM PS8132 arrived from the postman yesterday (suspected air leak here too)
  • Speedometer - Needle is dropped to the bottom, and does not work. No idea if it’s disconnected at cluster/transfer case/transmission end or gears are broken. Transmission shifts pretty fine though and the dash/cluster/steering column totally looks like its been messed with.
  • Fix the 2 inch or so play in the steering box.
  • Glow plug system - Relay gets power to right posts on key-on position, but nothing happens after that… can’t even get signal to the WTS light cable. I have one GP that is dead/doesn’t light up test light. However, I don’t have the tool to get two of the GP’s out to replace them due to the hard lines running over top of them. Don’t even think a skinny 1/4” drive extension would fit well enough.
  • I might bypass glow plug system for now and just heat the whole block with a Lower Hose Heater/Pump for coolant system. Thoughts? I don’t want to mess with dropping the starter to put in a factory style block heater in that freeze plug spot. Don’t trust myself enough, and seems like a LOT more work for something I don’t really need in my new location. I can handle having a easily accessible and noticeable coolant leak.
  • Get brakes looked at. The pedal is a little squishy, but gets firm after a few pumps. I have not worked on a Dually before, and have no idea about the drum brake scenario back there. Might be squishy due to leaky vacuum booster? Not sure if that is used on this truck, but there is certainly a vacuum pump doing something. I have to get new tires all around anyway, figured the shop that does that can at least look at my brakes for all the profit 7 tires will get them… lol.
  • Might flush the cooling system when/if I put in that in-line heater. A buddy of mine recommended flushing and switching from green coolant with SCA to the red style? Says all the semis, buses, etc he see’s use this stuff instead. Thoughts?

This leads me to the root of my question. What else would you look into/fix/check on a truck that has been sitting for a year, with a relatively unknown history, before a 1200 mile move? Do you have any opinions on the problems/things I would like to fix above?

Thanks in advance, I know that there is a lot to unpack here, I just really would like to not wrench on the side of the road, in the winter, during a pandemic, with most of what I own!
 

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You should never need ether, in fact it can be dangerous in high compression diesels like the 6.9/7.3 IDIs.

Recommend going through the glow plug system and make sure it is operating properly. Experience has shown it's best to stick with genuine ZD-9 glow plugs.

1993 F350 Crew Cab Dually
7.3L IDIT with a Banks Sidewinder
ZF 5-spd manual transmission
 

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Second what Rollfj said. It sounds like you about covered it. The long start might be your glow plugs, doesn't necessarily have to be an air leak. As for the brakes, they probably only need to be adjusted closer to the drum, but I would pull the drums off and check just in case the shoes are worn down. Yes you should flush the cooling system, but I usually put the cheapest green antifreeze I can find in it. If you keep the block clean cavitation won't happen as easily, so if you don't know what's been done to it recently, flush it and put fresh antifreeze in it. After that I usually flush every couple of years. Bring tools with you on your trip, because old trucks like to break, and enjoy the scenery (especially through ST. Louis)
 

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Discussion Starter #4
Thank you both for the comments!

I got the fuel filter replaced, re-primed and bled. The glow plug relay and plugs arrived, and I put them in today. Viola! The GP system worked 100%, WTS light bulb even lit up. I cranked for 10 seconds, and the the the engine roared to life!

When replacing the glow plugs, one of mine was much more dirty then the others. Coated in a viscous blend of what I assume to be unburnt fuel, oil, and grossness. There was a slight sheen to it, making me wonder if there was some super small shavings of metal in it. I have an appointment with a local shop that says they've worked on plenty of these engines over the years, so I kept this specific plug with the buildup in a baggie for them. They are "diagnosing" the truck, getting me new tires all around and double checking my squishy brake scenario if it "checks out."

The engine doesn't seem to have a miss, but certainly is noticeably "working" to warm up. I blow some smoke at startup, idle, warmed-up idle, and more when revving. I have not worked on diesels before to know the colors and smells real well. However, it seems to me to be white smoke the whole time. Very strong smelling, lingers after engine is off, and harsh. Certainly not burnt coolant, but could be oily.

The fuel in the tank is probably 7+ months old, and who knows if the previous owners ever ran stabilizers. I have half a mind to take my air compressor charged up in the back (two tires have a pretty active leak... lol), tools, dump some fuel treatment in the tank, and go for a good drive. What I found on that glow plug kinda scares me though. I would hate to have the start of a failing ring, and then wreck that cylinder wall instead of having a simple piston swap job.
 

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Everybody neglects packing their front wheel bearings and U-joints.
 
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Discussion Starter #6
Thanks LMJD - I have never done wheel bearings.
 

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Discussion Starter #7
While I am waiting for next week to get into the shop, and the engine seems to be running good - I thought that I would look into a few of the other things on my list.

The speedometer doesn't work in the truck, but when I drove it last week after getting it fired up for the first time, it seemed to shift pretty great. Nice and fluid, no jerkyness. Granted I probably only got to 45 MPH, but it still went to 2nd and maybe 3rd after I released the heavy throttle I was giving it to accelerate to speed. All of the posts I am finding with my searching are showing problems with BOTH the speedometer AND bad/erratic/hard shifting, not just simply a non working speedometer.

Anyone have an opinion on this? I am heading out to wrench on it after lunch!
 

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That's a cable driven speedo, it could be a broken cable or a strippped driven gear at the trans end of the cable.
 

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Discussion Starter #9
Hey all!

Thought I would post a follow up. I have taken care of a lot of things since first posting.

Startup is still much faster, but a couple more cranks that it should. I have a little fuel leaking out around an injector cap after replacing, so digging into that soon.

Local junkyard trip yielded a replacement steering shaft to fix the broken clip/retainer that mine had. This fixed up the 3" of play the wheel had, but someone tried to get rid of that play with over tightening the steering box. I need to adjust that looser. Also snagged a couple badges from the truck! Going to be rolling in style!

None of the trucks there had a E40D, so no luck with a speedo swap.

Truck goes in for new shoes and a brake assessment this week!
 

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Discussion Starter #10
Anyone want to try to help me understand what the heck someone did to this trailer wiring? It looks like they might have spliced into things to make a 4-pin blade adapter, and then cut it off later?

It has a 6 pin connector in the bed, and it lines up with the diagrams shown here when I supply my own ground to the meter, the ground terminal doesn't work - Trailer Connector Pinout Diagrams - 4, 6, & 7 Pin Connectors

So I have a ground issue. There is a screw and a clip right behind that rats nets of wires you can barely see in this picture that probably was the factory solution for ground? The screwy thing is that I have 12 volt on the thicker gauge black wire that's spliced down there, that runs up to that 6 pin it seems along with three other wires. I would have thought black means ground...

The two wires coming in from the left side are black and maybe brown with a blue stripe. The black one seems to be a ground, and the brown/blue stripe gets 12 volt with running lights on. They both were not connected to anything.

Anyone know what those other terminals are for? One has 4 pins in it, and two have just a single pin.
158703
 

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Discussion Starter #11
I meant to add a bit more information before I posted, sorry!

The center pin which is supposed to get 12v, does not get anything. Neither do the trailer brakes pin, however I suppose that's because I do not have a electronic trailer brake module hooked up? I kinda thought that this would get power when the brake lights did, however I have never worked with electronic brake trailers before.
 

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For the electronic brake wiring, don't go by anyone's hillbilly wiring on that truck. Get a diagram for the controller, and your truck, then go from there. For running lights find the one that has power for only lights and hook it up accordingly. Then find the appropriate wires for turn signals and wire them accordingly. then the brake lights, I think they're a separate circuit. Ground simply goes to a good frame ground. As long as the trailer has a ground hooked up, lights will work, but every time the ball separates from the hitch, the lights will blink.
 

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Do you happen to know a good resource for truck diagrams for my 1990 F350 7.3? I have been creatively googling, but everything is filled up with some adds/trash websites claiming to have a schematic or a sketchy paysite. Knowing the FORD OEM colors referenced to what they mean would be great. There is some hillbilly ingenuity at the end of the original runs, so I should be able to reverse engineer them. For hypothetical example: my black should not have 12v. It would be great to know that the brown and pink wire connected incorrectly to it was actually for constant 12v, etc.

I was able to figure out most of them at the 6 pin, but no idea what they are before the pins/at the termination to that harness. I suppose I could rip that out of the bed and investigate, but this copper seems pretty stiff and fragile after 30 years.
 

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If you google the manufacturer of the brake controller, you should be able to find a diagram at least for it and how it wires up to your truck
 
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