7.3 idi

Fordfan90

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I'm looking to buy a 1990 7.3 idi diesel non turbo with a 5 speed. I use to own a 1990 7.3 idi with auto trans but my question is how is the manual in theses? my other question is the guy said it starts then dies then takes awhile to get started then he said you have to give it some throttle keep it running then it's runs fine. So does anyone know what that could be?
 

DaveBen

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I owned a 1992 non turbo with a ZF-5 and I liked very much. Pulled very nicely when I was towing. Go for it. The starting problems is probably air in the fuel injector lines.
 

Fordfan90

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do you if a fuel return like kit would fix the starting problem?
 

pelky350

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Return line kit may fix the problem, it depends on where the air Intrusion is coming from there are a few points that are common for air in the fuel system. Usually when you look under the hood at the motor and fuel system you will see wet spots on the motor where fuel is leaking indicating where a likely source of the air in the fuel is coming from in most cases. Usually a fairly easy fix. As far as my expierince with the zf5 it's a definite winner mines taken some serious abuse through it's life and still going strong. Most would recommend it over the auto trams of these years for reliability and durability
 

icanfixall

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Welcome to the forum. Sounds very much like you have air getting into the fuel system. The return lines need to be tight. air gets in before you see fuel getting out. Think of it the same as a straw in fluid. Put your finger over the end of the straw and draw it out of the fluid. Nothing drips out but let off that finger and its all gone. Our fuel system is that same way. Even though our mechanical lift pumps have a check vale that does not mean it works right. Most of the air gets into the fuel system thru the returns so a kit might fix all this. Look at the injectors for a wet area. If you see that then you know something is leaking. At the filter inlet fitting you have a seal in that brass nut. Also the same type seal in the outlet line fittings from the filter head to the injection pump. MANY times they harden and leak. Easy to replace but try snugging them up first. If they are all the way tightened then you need to replace these seals. the inlet is a 3/8 and the outlet is 5/16. They are commonly known as olives. Any good injection pump repair shop has them. I recommend purchasing from 2 of our members because they sell the better return line kits.. Both install viton o rings in the kits. Agnem or typ4 both are highly recommended on this and many other sites.
 

Macrobb

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The weak point on the ZF 5-speed is the synchros. Mainly because they last forever otherwise...

All the 5-speed trucks I have tend to be a little 'finicky' going into second(you either have to be going really slow to downshift, or rev-match), and several of them 'clash' a little going into 3rd - you can feel it bump a couple of teeth sometimes.

Reverse can be a little iffy as well; once you get the feel for it, it's not a big deal, but it's not hard to put it in reverse... and find out the transmission isn't /in/ reverse.

It's all due to worn synchros... but considering the transmission probably has 240-300+ thousand miles on it, that's reasonable.
Even if your truck has *all* of these issues, the transmission isn't going to go out any time soon. You either A, rebuild it or B, ignore it and learn the
'feel'. I've put 40K on a truck that had all of those issues... and it still has them the same as it did 40K ago. It didn't get worse, or cause me issues or anything.

Also, while the 5-speed ZF transmission in your 1990 is a zf s5-42, meaning it's rated for 420 lb-feet of torque... Multiple people have run more through them. Sometimes a /lot/ more. IIRC, Justin @ R&D was putting over 1,000 ft/lbs of torque /at the wheels/ through a zf s5-42 before he blew a connecting rod, which means the transmission was handling more than that...
 

pelky350

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Do I have a zf s5-42 being my truck is a 88? What's the difference between that and a zf5 from a newer model idi?
 

pelky350

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Oh I wonder how much torque I'm putting to it now? a dyno one day is needed just not done with mods yet lol intercooler and maybe turbo upgrade are left now
 

Macrobb

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Oh I wonder how much torque I'm putting to it now? a dyno one day is needed just not done with mods yet lol intercooler and maybe turbo upgrade are left now
With my 110 CC pump and Banks turbo, I made 248HP at like 460ft-lbs of torque at the wheels. The 110cc pump was good for more; the turbo couldn't do it.
Your clutch will be the weak point before the transmission has problems.
 

austin92

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With my 110 CC pump and Banks turbo, I made 248HP at like 460ft-lbs of torque at the wheels. The 110cc pump was good for more; the turbo couldn't do it.
Your clutch will be the weak point before the transmission has problems.
Pretty impressive numbers :). Southbend clutch makes a flywheel for the idi's that allow you to use their 7.3 powerstoke clutches. I have one sitting in my closet waiting to go in that's rated for like 650ft lbs


Sent from my iPhone using Tapatalk
 

pelky350

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I got the luk 12.25 smf clutch in now, dual mass broke and clutch couldn't hold on anymore. That's where I'm at the 088 ats isn't enough air for the 90cc pump I can cloud a whole block pitch black until the turbo spools to at least 10psi lol once it reaches 17+psi I get a slight cackle from the exhaust and just a lighter haze from the exhaust but I don't hold that too long as I don want to kill my motor lol have you got on the dyno since your turbo upgrades? I seen your last YouTube of the .63 ar housing screaming down the road. What intercooler are you running?
 

Macrobb

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have you got on the dyno since your turbo upgrades? I seen your last YouTube of the .63 ar housing screaming down the road.
Sliiiight problem there. Just after I made that video, I finally got it tuned in, it was running strong... pulled into my dad's place on Black Friday. Started it up on Saturday, and it was running horribly. Revved it up to 2K(in neutral) and it threw a rod...

So, no more S360 until I can get it yanked and rebuild it.

I just put the 110cc pump in the '93 there, my new DD, and it's nice! I'm not pushing it /too/ hard yet, and I'm probably starving it for fuel a little, but I can hit 16+ PSI really quickly if I floor it. And, thanks to the aneroid("Hypermax smoke puff limiter") that I have on there, it's pretty cleanly done.

What intercooler are you running?
None. On any of the rigs, yet.
 

shawn deere

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Also if the clutch/tranny sounds growely it pry has the dual mass clutch replaced with a single mass (more noisy) clutch.
The growel at low rpms might not be a problem
Dont plan on hauling 25,000lbs at crusing speeds with it, but itll pry get it there
 

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