7.3L Mechanic?

[scout man]

Anyone on here a true 7.3L guru? I'm really looking for someone who knows this thing in and out. I have been fighting some issues for a long time now and ready to see if someone else can point me in the right direction. Not looking to keep throwing money at it though, so I am really looking for someone who knows these things like the back of their hand. I have done a ton of stuff to it, but I am still having a few problems that I have not been able to pin down. I will pay you a reasonable amount to check it out and tell me what you think. Thanks!

[redneck23ms]

what problems are you having? i have a 7.3 as well

[dieseldoc]

Progresive auto and diesel in south Englewood is who I took my stuff to.
They have a emissions dyno for tunnijg and annual tests.
My 91 dodge cummins 12v needed alot of tunning time to pass emissions and new injectors.
$750 out the door. Granted the pump was in jeed of rework as it was just cranked with the big fuel pin
But they did well with the truck.

As a diesel mechanic ky self it was just time I didnt have let alown the access to a dyno.....

What are the issues you are having with your 7.3
These are symple engines but they have quircks like the injector wire harrnesses will rub and then blead over thus not firring right....
The Hi pressure oil pumps are very picky....thus the oil has to be clean....dam HEUI injection....
Hydraulic Electric Unit Ijectors are some temperamental units.

[scout man]

first problem: difficult cold starts, with significant white smoke - until I start driving then it clears up real fast
Things tried: Glow plugs are less than 2 years old.. one is testng a little off right now, but the rest are good. UVC wiring harnesses have been replaced in the last 6 months, and the glow plug relay replaced within the last month. It will start, but I have to cycle the plugs several times, and it still struggles. Will smoke even when just mildly cold.

Second problem: I have never had very good boost with this truck. After I did new injectors a few months ago (stage 1 single shots) things were real smoky (black) and my Boost levels were about 16, and my EGTs were shooting over 1200 degrees without really trying hard. I had the programs tweaked and got rid of the black smoke, but egts were so high I couldnt tow anything. I installed a GTP-38r turbo, and new boots. no change. with the new turbo boost would build fast, but peak at about 14psi (manual wastegate cranked down so it cant open, for testing reasons). EGTs still stupid high.
Possible solution: I might actually have fixed this today. I ran a boost leak test, and found a very slight leak. More importantly I cleaned out my air filter. While I didnt get that much dirt out, I think the air filter is too restrictive, as I suddenly am boosting to about 24psi and the EGTs seem (on quick examination) much more reasonable. Currently its an AFE cold air intake, I think I might try something else, as that seems to be not allowing enough air in.

Third Problem: I might have just figured this out today also. Problem was under significant torque, I would get a loud metal on metal squeal. I thought it was the turbo, since I knew the old bearing was going out. It wasnt the turbo. Then recently I started hearing it when starting from a dead stop, just for a second or two. Started thinking maybe it was the transmission starting to have trouble (or I screwed up the turbo install). Then today I opened the rear differential and found a lot of gunk and a missing tooth on the ring gear. I am thinking maybe I have unrelated problems, and the noise I was hearing was the axle all along. I am assuming some gunk got in the bearings and they are not healthy. Looks like I will be doing an axle rebuild.

Long story short, I may have just figured a lot of this out, but this truck has been a serious pain in the ass, and I am strongly considering selling it and moving on. As soon as I fix one problem, 2 more problems arise.

So far I have replaced:
clutch
entire coolant system (radiator, water pump, etc)
wheel bearings
brakes
many u joints
turbo
rear diff
front driveshaft
lots of sensors
injectors
glow plugs
UVC harness (several)
many glow plug relays
air intake
rear suspension
emergency brake pedal (several)
turbo boots
up pipes
alternator
and probably a lot more

Point is this thing is a damn money pit. I have never owned a truck that needed this much maintenance. I keep thinking I have replaced enough that I shouldnt have too much trouble anymore, but everytime I turn around something else breaks. The big frustration I was having was the high etgs, low boost. Hopefully I have figured that one out though.

[AddictedOffroad]

Rocky at Rockin S Diesel in Fort Lupton is a 7.3L master.

I am good with them as well, but its not "exactly" what I work on. But I have owned 6 of them and I am the only one allowed to touch one of my trucks.

[dieseldoc]

And now you understand why so many truck owners go to the cummins.
I understand all the manufaturs have there issues.
But as for the engine cummins by far the more reliabe you find in a light to heavy truck.
Hell even International has gone back to Cummins engines.

I am sorry you are having issues with your truck.
The cold start issue is inherently the design of HEUI injection system.
These engines halve to see 600rpm before they will light off.
As we go onto cold weather the oil is slugish at best.
These trucks do far far better when plugged in over night.
I know it shouldnt need it but as you stated the engine runs black then clears up.
This is the cold cylinder vetting warm from running.
Clearly the pre heat is not working properly.
So you may have weak glow plugs and the one that is not working thus hard start.
We used to keep 8 on hand in the small landscao shop I worked in as they fail so offten.
Same with the relay we kept many in shop and extras in each truck.

As we are in colder weather a lighter oil is the 1st step I would take.
Next get rid of the AFE....the oil bath filter elements choke the infake as the get dirty and thus
The turbo cant spool up. A good dry filter will help with this issue for sure.

The rsar end all I can say is rebuild it a good quality gear set and quality bearings.
Maintance is all one can do about that issue.
They go when they go.

[Brian]

This site -----> http://www.ford-trucks.com/forums/forum31/

It has been a great place to with help on my 2000 7.3L. No real drama and some real knowledgeable guys there. Searching there alone might get you all figured out too.

[scout man]

yea, Ive been through all the forums, bottom line is I keep fixing what I think the problem is, and not really getting anywhere. Such as the injectors for example. Several things went downhill after the brand new injectors, which was not the direction I was hoping to go. Getting tired of the 1 step forward 2 steps back thing. I have fixed so many things on this truck and spent so much money, and at the end of the day I always feel further behind then when I started. Expensive prospect to dump this truck and get something else though, then have to start over with repairs and stuff.

Dieseldoc - thanks for the feedback. The Afe actual is a dry filter though. They make both options. I fixed the cold start issue once in the past, before the new injectors. Still didnt like to start in the cold, but it would without too much effort, and the smoke wasnt nearly as prominent as it is now. Maybe that is just because of the single shot injectors though.

[dieseldoc]

Sounds like it may be the biggest culperit
Its the biggest change so start there.

[gm4x4lover]

Mine has never liked to start in the cold either. I have never been able to fix it also. Brandon does have a point, try switching to synthetic 5w40 diesel oil. It may make a huge difference.

[redneck23ms]

Mine doesn't like to start when it's cold either. Just nature of the beast I reckon.

[flashboiler]

I have a 2001 7.3 F350, wasn't really looking for a diesel but my friend was selling it and he takes good care of stuff.

Heard all the cold start nightmares... Mine fires up 1st hit no matter how cold, once in Wyoming snow bashing it sat all day in 40mph winds and it was below zero when I fired it up, started right away.

It's always ran rotella synthetic which I'm sure helps. $100 oil change DIY! 4 GALLONS of oil. Crazy!

[redneck23ms]

mine seems like it used to start better when cold but seems to have gotten worse lately. checked glowplugs from the harness plug and all checked out fine as does the glow plug relay. may try a new relay anyway and see if that helps. i am running 15-40 rotella may go with synthetic next go round but winter will probably be over by then.

[dieseldoc]

so in my experiance with these truck they have small ground and positive cables on the battery.
we used some 1/o welding wire, and good lugs to build cables.
Helpped more than one would think.

The biggest thing with these engines is getting the HUEI injectors up to pressure.
The high pressure pump is fed from the low pressure egine pump.
The harder it is to get the oil up there the longer it takes to start.

The 6.oL has hjgh pressure cross overs that will bleed out.
This makes that turd evrn worse of an issue.

Alex- yup nature of the beast, these are good trucks but the oil system should get preheat as well as the air!

So if someone ever figurss out how to preheat the oil system as well as the in comming air with these engines and bam....great start up and thd 7.3 reliability!

I still think its a good home for P -pump 6bt cummins but hey not everyone has a money tree to do 15k engine swap.

[Bob]

I use Rotella synthetic 5W-40 and it makes a HUGE difference in cold starting with the 7.3 and works well at any temperature. I also tried the Rotella Dino 10W-30 in the winter but it isn't as good and hard to find as well.

Since I don't put that many miles on the truck, I just run the same synthetic all year rather than swap to cheaper 15W-40 in the summer.

But if the glow plugs are failing it will be hard to start no matter what oil is used.

[dieseldoc]

Good to hear you are having good results with the lighter synthetic oil.
All the manufactures have gone this way in equipment and trucks.
So swapping it into the older engines shouldnt be issue.
I get the cost....you guys need 4 gallons....us cummins guys need 5 gallons.
And us manual trans guys have anothe 6qts in the trans to....

The biggest thing with glow plugs is resistance.
If any of the system is beginning to have more resistance it will make these trucks a total suck in cold weather.
Thus plug them in. Even us cummins guys benifit from this.
Hell I used to have 140* in the engine unless it was 0* or less.
Nice to fire up and have heat.
Having the engine warm already is a good thing for the fuel as well.
As the recycling fuel is already heating the fuel tank and lines.
Thus less chance of gelling on the freway in realy cold conditions.

Fueal heaters are great but hard on the charging system like the preheat stuff.
It pulls a ton voltage and makes the alternator work realy hard.