Looking for a excursion to pull a enclosed car trailer. What are the common problems that I should look for in a used 7.3?
I don't mind higher miles on the engine, I was thinking about having a good friend of mine rebuild it.

 

Plenty of other threads with the same question: https://www.ford-trucks.com/forums/8...-problems.html

 

Sorry if I offended anyone. I first tried to use the search function, but my in-laws computer would lock up after every search. Thanks for the link.

 

Rebuilt transmission, replaced alternator, end links, replaced leaf springs, steering box, rebuilt turbo, fuel bowl, just off the top of my head. Some of this was done as upgrades and some out of need!

 

Welcome aboard!

You aren't offending anyone here, nearly all of us started off here asking some very general questions too. We have tons of guys (and gals) here towing with these big wagons and we have built up a massive amount of info about mods to make them better for that kind of work. Check out the Tech Folders at the top of this forum thread list to find hours of reading material. You may also want to check out the 7.3 forum here at FTE for even deeper insight into the legendary 7.3 PD.

 

Definition of "problems" vary greatly and are usually categorized by dollars to sort them out.

Most of the "problems" I see with the actual 7.3 engine are user induced from either hot rodding them or lack of maintenance. First sign of high EGT's are broken exhaus studs, changing 15 qts of oil gets expensive and some people will stretch change intervals to far, don't even get me started on k&n style air filters, the brakes and steering rely on a .25 cent nylon washer between the pump and hydoboost that is failure prone when running large tires.

Ford did include a few problems with the 7.3, The Fuel hard line from the filter to the head rubs and ruptures. The Cam Position Sensors have/had reliability issues. Air box lid warps. Cruise control switch likes to catch fire ( recalled )

The reality however is that a well maintained 7.3 will live well Beyond the chassis components.

Chassis "problems"

People like to claim the excursion has a "wandering" problem but what they really have is a maintence problem. The first sign of worn suspension/steering parts is wandering when driving down a straight flat hwy.

Internet lore will say the transmission is weak. I would counter that it just isn't as stout as it could have been or needs to be if you run large tires or tow hard.
Big tires and or towed hard a trans may last 70k. Many folks get 200k + out of a trans that is not abused. But since transmissions are expensive and have a limited life span they are often considered a problem even though there really is no inherent issue other then knowing what not to do.

Anyhow... Just my observations from owning several 7.3's

 

Well said by pirate ^^^^. The actual only things I have had to replace were 1 hub on passenger side, alternator, front end links, brakes as their times was up, the turbo up-pipes as they were leaking, and the batteries. Rest has been to upgrade and get the truck running to my liking.

 

Take the above mentioned brakes as an example.

The glide pins can accumulate crud or corrosion and get sticky leaving you with a brake that drags. While it may not be the best design I would catorgize it as a maintence issue more then a "problem"

Maybe a better question for a potential 7.3 owners is how much work or cost is involved in maintaining a 7.3 ( or any large diesel truck ) or what do I need to look for to try and determine how the vehicle was actually maintained.

Bottom line is parts wear out but overall the 7.3 trucks deliver a solid service life out of their parts and systems. And there is a plethora of aftermarket parts and swaps available to suit just about any need or desire.

 

I love my 7.3 but one thing for sure is its a slug from a standing start It feels almost the same to me with a 8000# travel trailer as driving it to work with just me in it.

As for fuel mileage I get 13 MPG city and 16 MPG towing my my TT on the highway and 23 MPG on a road trip with out the Trailer

My Truck had over 337000 Miles on it now and the worst problem I have had is the pickup in the fuel tank came off and I could not use the last 8th of a tank of diesel

 

Occasionally I will drive mine in no tune mod and it is indeed a dog.

Drove my buddies stock 6.0 all last week when I was visiting and while my tuned 7.3 smokes his in a drag race the 6.0 no doubt has great driveability compared to a stock 7.3

 

I have read that people have problems with tuning the computers. Is this with programing of the unit of with the performance?

 

Not sure exactly what you mean...most people buy a tuner or a chip for a performance upgrade...more HP and torque. Some let you adjust the parameters like shift points, firmness etc. I have a 6-position TS chip with Gearhead tunes...before that I had an edge tuner. I have never heard of any issues with the programming. There are a ton of vendors and choices and not everyone is the same.

 

There's really not much to cover over what pirate and the others have said.

Transmission especially, the Internet has given the 4R100 a bad rap. Mine lasted 250,000 miles completely stock, the last 75,000 dealing with 35's and probably double the power it was intended to see. 10psi boost launches, ridiculous over weight towing, and I will admit to some owner neglect regarding maintenance.

Tuning the computer, absolutely not difficult to tune. Just google 7.3 chips and tuners and prepare for more options than you can easily consider. Not saying they're all safe or smart choices, but they are out there. That's a whole other can of worms though.

The 7.3 is a reliable motor when taken care of, and can surprise you when you get some money into go fast goodies. The kill list for mine is growing, and while not a race truck it will certainly surprise the hell out of you. Evo 10? Rolled on (barely). Harley 1200? Rolled on. Mustang GT 5.0? Rolled on til 9200 pounds and aerodynamics took over. Blah blah and blah.

Is it a little outdated and dinosaur-ish? Yep. Reliable? Yep. Still commanding a decent price tag considering their age? Still yep.

 

Problems with the 7.3,
Oil pans can rust to the point they leak oil. Proper fix is pull the motor and replace with a Moroso pan.
Turbo pedistals can leak.
Engine blocks can cavitate from lack of additive in the coolant.
Glow plugs, glow plug relays, glow plug modules (most X's have the module).
Under valve cover harness (UVCH) shorts and failures.
Injector cups, injector O-rings, and injector failure.
Heater element in fuel bowl.
High pressure oil pump (HPOP) leaks at lines and pump failure.
ICP (injection control pressure) failure.
CPS (like mentioned recalled most should be fixed by now).
IDM (injector drive module)


Done all the above except the cavitation problem. The 99 F250 needed a oil pan at 330K miles at which time did the turbo pedestal since motor was out. Did driver side injectors and IDM (injector drove module/THE PROBLEM) in the 99 F350 around 220K miles. This Spring going to swap them for PIS or Swamps injectors 175cc as it starts hard when cold. Did injectors in the 02 X at 310K miles went with swamps 175cc, did ICP at same time. Did an HPOP in the 99 F250 around 260K miles and one in the 99 F350 around 270K miles. Turbo was rebuilt under warranty on the 99 F250 at 55K miles, other than that no turbo issues on them. Did several CPS's well before the recall but since the recall never touched one.


The tranny is like others mentioned a weak link. If kept stock they can hold up quite a while but if chipped and or towing a lot they can fail.
99 F250 tranny failure at 83K miles Ford rebuild lasted until 252K miles, current Ford rebuild sitting at 90K miles.
99 F350 tranny failure at 250K miles but it was slipping for years. Ford rebuild sitting at 30K miles.
00 X original tranny 278K miles. This vehicle has been my most reliable by far.
02 X original tranny 314K miles.
03 X original tranny Approx. 140K miles as it had a cab fire, the parts vehicle.


In terms of chips or programmers the best currently on the market is the PHP Hydra. Most are running 10+ year old technology. The Hydra you can get custom tunes sent to your PC and change the tunes yourself. I think the rest you have to take out of the truck and send in to be changed.


BUT, before you start looking into chips or programmers you need to get gauges, tranny temp (don't trust the 02+ factory gauge), exhaust temp, and boost. A larger less restrictive exhaust will help lower EGR's and a good air intake is important too. Like others have mentioned the worse intake is a K&N in a factory box. My 02 X is running the 175cc swamps injectors, Hydra with swamps custom tunes, S&B box. Daily drive on either stock or mild daily setting. Done a couple launches on extreme race and it's hard to believe what it will do to a 4 ton vehicle.


As far as the 7.3's not a lot changed from year to year except in 01 Navistar started using PMR's where before that they all had forged rods. Believe in 01 the HP & TQ numbers got bumped a little. The PMR's are said to be good until 425-450HP. Believe the early 01 MY has forged rods. You can remove an inspection plug and see what rods your motor has.


IMO, the best 7.3 Excursion is the 2000 MY as they all should have had the forged rods. In 2002 MY the X started getting better creature comforts however.

 

Doug, your "problems" sound like maintence issues and or just worn out parts more then actual problems inherent to the design or manufacturing of the 7.3

It's sort of a given that bare metal is going to rust if your expose it to salty roads or wet conditions. A coat of paint every few years is a simple preventivitve maintenance procedure.

Like I said, everybody has their own definition of what constitutes a problem but a service life of 1/4 million miles from a Module or injectors seems reasonable to me.

To me the "problem" with the 7.3 fuel system was that back when these trucks were made diesel was much less refined and was much dirtier then it is today, a more robust fuel filteration system could or should have been installed. Now that we have cleaner fuel the filteration system is adequate but the damage has been done and many people replace the injectors with the cheaper rebuilt units which just don't last as long or as you mention work as well as Factory units.