I bought a '94 Super Duty a few weeks ago with the IDI 7.3 non turbo motor and auto. I replaced the starter, lift pump and got the glow plugs working properly so it's drivable and almost work ready. I pulled my 9 ton trailer and PC-50 to the job with it. The truck has 74,000 miles and is clean. The only thing I'm worried about is that it runs out of power around 2000 RPM. It will rev to 3 but the exhaust "raps" (like headers and cherry bombs) and it misfires. I think it's running out of timing. Is there a timing advance in the pump that could be stuck? It smokes blue at idle and smells like fuel. Maybe the timing is back too far? It there a procedure to check the pump out in the driveway? I tried searching but the hits are all over the place.

Thanks for any info.

 

how long it been sitting? did you pour some diesel fuel additive in there?
did you pull the fuel filter and see if its plugged up?
check your air filter too of course,while your at it,and cut that big bowl off the lid.

 

I agree, change the fuel filter and fill it with diesel kleen and see if that helps any.

 

The fuel filter is new. I put some K100 in the tanks. When I replaced the filter, I filled it with ATF. The idle lopes a little bit, enough to rock the truck slightly. The steering wheel was installed 90° off which I take as an indication that the truck has been hacked some. I'm welding a new floor in the dump body tomorrow. The PO used it as a cement mixer and rotted it right through.

 

I'd suspect injectors and would consider pulling them and getting them pop tested and check spray pattern.

 

im thinking you will be looking into a turbo if your gonna be doin a lot of pulling.fresh ip and injectors can do wonders though

 

a fresh ip and injectors can do even more wonders when you bolt on a turbo lol.

 

ya id deffinatley turbo her and maybe go with a little bit bigger injectors also if you ad a turbo

 

you dont need any special injectors the factory ip has way more than enough adjustment to overfuel your truck.and to my knowledge there is only 1 company that makes bigger injectors and they are $$$$$$

 

I removed the biggass bulb in the air cleaner today. The filter is new. The truck runs much better but still isn't right. I'm going to try to get a year out of it before I even think about a turbo. It breaks up pretty bad at higher RPM (like 3000 warm....2500 when cold). I'm moving my PC-50 tomorrow morning. Just 3 miles but that's 9 tons behind a 9000lb truck.

 

yeah a turbo will help im sure,but you likely have 4.10 gearing at least id guess,and likely even lower in the f450.
somethings for sure not right with no more power above 2k,and missing real bad.
generally,you want to fix troubles before upgrades like turbo's of course,im sure that suggestion was after the trouble was gone though.
it does sound like poor ip/timing/injectors.
she should be real smooth,and sound SWEET when hauling.it has a really nice growl (not exhaust tone i mean right from the heart of the engine,very distinct and powerful grunt sound) under a good load.no missing and popping like your describing.

when the engines cold,does it have more of a "rattle" sound to it than when it's warmed up?
do you have a local diesel shop that can check your timing? - if so,take 87crew's advice and have them pop test,and check the spray pattern of the injectors-BUT check the price.our IDI's are so much lower cost to maintain than modern diesels,it may cost less to just replace all 8 injectors-no kidding.

remember.her peak hp is @ 3000 rpms and peak trq is @ 14000.so don't expect anything extra over 3k rpm of course.with your low gears,this isn't going to be at high speeds.

(back in '94 the "super duty" name.actually F-super duty (f450) meant much more than it does today lol.what were the axle ratio options for these,anyone know?)

 

I think most were 4.56 and 5.13 gears.
Before I started throwing money at it with those miles I would empty the filter and fill it with a good additive(cleaner) and crank it just long enough to fill the system with it and then kill it and let it sit overnight. I would also take a good look at the exhaust, it was junk new and may be trying to stop the muffler up now.

 

Thanks for all the advice so far. Any take on the "rapping" (or "BLATTIN'!" as we say upstate) exhaust sound? This diesel doesn't seem to crackle much and it does quiet down a little bit when it warms up. It knocks ok at idle but it's been many years since I worked on these diesels at the Ford dealer. I worked on these things when they were new but I don't remember what they're supposed to sound like. Louder then the powerstrokes right?

I don't intend to go street racing or off roading with my mason dump. My only concern is grossing out at close to 30,000 # and encountering a steep grade. There are plenty of short 15-20% pulls around here and I don't want to stall the trans/TC on one and come to a complete stop. I need a HP peak at ~2000-2500 so I can at least get a good head start and the engine feels like it would have that if it didn't start running out of steam at 2200-2300 RPM (better since I took that bulbous protruberence off the bottom of the air cleaner lid).

I figure (guess) my gears are 4.10:1.

 

bulbous protruberence.
yeah,that was fords idea of providing a quieter idling diesel.we call that thing a soup bowl,though thats even better.

the "blat" is usually from a bad muffler.though not a plugged up one,but a pretty much empty one.

your going to want a few mods for 30k gross weight once you fix your (most likely) fuel/timing issue such as:

exhaust
turbo
ram air
egt gauge
trans temp gauge
oil or water temp gauge
torque cam
moose pump
big trans cooler,trans cooler,trans cooler...and don't forget a big trans cooler.
just search for those here to learn all kinds of methods/upgrades.

back to the problem at hand:
missing,blue smoke,and not wanting to rev smooth beyond 2k:
https://www.ford-trucks.com/forums/9...e-smoke-2.html
https://www.ford-trucks.com/forums/9...gher-rpms.html
https://www.ford-trucks.com/forums/9...runs-cold.html
https://www.ford-trucks.com/forums/9...ky-smokes.html

this guys timing is off.the added cetain in the diesel supplement is compensating for his timing being off/retarded:
https://www.ford-trucks.com/forums/9...lue-smoke.html

notice,he tried to ballpark his timing:
https://www.ford-trucks.com/forums/9...0-rpmhelp.html

https://www.ford-trucks.com/forums/9...e-problem.html
https://www.ford-trucks.com/forums/8...nder-load.html

he put in new injectors,but he doesnt mention adjusting the timing after.naturally the timing is all off still:
https://www.ford-trucks.com/forums/8...lp-please.html

this guy made the same mistake too:
https://www.ford-trucks.com/forums/8...ing-rough.html

"I don't remember what they're supposed to sound like. Louder then the powerstrokes right?"

sound like powerstrokes with high advance on at startup and then quieter than the PSD when advance timing kicks off.

 

When you said K100, did you mean B100 biodiesel?

The exhaust smells like fuel and the rough idle tell me you need injectors cause some of them are not working correctly.
They are not snapping closed after the injection event.