Low end power issue 6.9 help!

[84diesel6.9nonturbo]

I put a new auto trans modulator in a month ago. Not the black striped one... its a purple line. Ive heard it should be black. It softened the hard shifting so i havent swaped it out yet. I do hear a torqe converter type of rattle for only a second or two, rarely, at the very slightest throtle while in gear?? Not sure what it is for sure but ive wondered about the torque converter based on some of these symptoms myself.

 

[chris142]

Just for a fun comparison. My last truck was an international with a sick gasser 392. Had 2 burned valves,flat cam,worn rings.ring gaps were .065+!!! It put out 197 HP and 300ft lbs to the wheels in that condition on a chassis dyno! Considerably more than a 6.9 does at the crank with all cylinders firing.

After I rebuilt it with a bigger cam and other minor tweaks it put out 270hp and 525ft lbs at the wheels on the same dyno.

So the idi is not a powerhouse by any means

 

[84diesel6.9nonturbo]

This is what I would do:
1. Have realistic expectations. A N/A diesel isn't going to be powerhouse, but it will usually be reliable and get you to the top of the hill.....just not in 1st place. My '88 e250 N/A 7.3 c6 does fine with 5-6k behind it. Haven't had more then that.
2. At a minimum, rent a meter and check your timing. I would plan on replacing the pump and injectors.
3. You have a c6. The Torque converter is probably original and pretty sloppy. I replaced mine with a Hughes Diesel Low Stall towing converter for mine.
4. Look for a truck in a junkyard etc with a 4.10 rearend. Swap out the axles
5. Hunt for a used turbo kit. Many times you can pick a used on for around $500.

Your truck will get the job done, you will just need to invest a little time and $$ in it. Most likely you will still come out ahead $ wise versus buying a good used Powerstroke

I Agree! Thanks for the details. Just what i was looking for. I thought id be running high gears if im doing 85 with some peddle to spare. I bet thatd get me by for a while so i can earn some more $flow$ to do the much needed injection system n turbo. All original gray paint on everything. H20 filter was so bad the media was falling apart inside and going into my fuel filter and injection system. Valve covers both leaked real bad and they seemed super loose.

Im going to pull my shims today because im thinking like one of you said. It could make it run worse if the ip can only pump at 80%. My best advice after all of this is... if you buy a used 6.9 make an apointment at orangevale diesel, in citrus heights, or whatevers near you... have them test the fuel pressure and injectors. All the tuning and cleaning in the world wont do a damn bit of good if youve got a weak injecton pump. Ive waisted a lot of valuable time sadly.

 

[riotwarrior]

Siunds like a multitude of things...

Original ip and injectors
Unkown health of engine IE leakdown and comp

Overloading a worn C6

Overly high expectations of the capa ility of said truck

This is what I am seeing...

My turbo 7.3 w c6 w 3.55 was sickly...c6 is a supersucker of power unless modded well....dont get me wrong great trans just power sappers...

Stuck 5sp in truck whole different beast now...still sick but can sometimes catch up to its own shadow....

JM7.3CW

 

[84diesel6.9nonturbo]

My hoe is mini. Its about 4-5k id guess, my trailer is 3k
Sounds like i need the gears yesterday and a remaned injection pump asap.

 

[riotwarrior]

My hoe is mini. Its about 4-5k id guess, my trailer is 3k
Sounds like i need the gears yesterday and a remaned injection pump asap.

4.10 changes rpm by bout 270 rpm from the current 3.55...a 5sp swap..adds 2 gears and changes truck dramatically....

I still need toss 4.10 in for my 4x to work...no front shaft now

 

[jayro88]

10k is probably way over the tow rating. My 85 has a 12k combined rating. The truck takes about 6000 of that.

Sent from my Nexus 6 using Tapatalk

If memory serves, 3.55/auto combos have a GCVWR of 12k, 4.10/auto combos are at 14k in the owners manual. My e250 is 6200 lbs with me and 2 full fuel tanks. That leaves about 6K with 3.55's and 8K with 4.10's.

My hoe is mini. Its about 4-5k id guess, my trailer is 3k
Sounds like i need the gears yesterday and a remaned injection pump asap.

If the entire trailer/back-hoe combo is 8k I would think a swap to 4.10 would help alot. With about 5k trailer/car combo I didn't have any issues setting the cruise at 65mph. I have a c6/3.54's. This was in foothills, so no big grades. On the biggest grade it kicked out of cruise about halfway up because it couldn't hold it. I gave it more fuel and it held speed fine.

AS far as the shift module, I think mine was green.......if you talk to someone knowledgeable at NAPA they should be able to tell you which one is diesel specific......but it doesn't have anything to do with you being able to get the load moving.

The stall of the factory torque converter is too high for a diesel. It slips a lot at lover rpms and sucks a lot of power. Replacing it with a quality low stall diesel one would help with efficiency. I would also recommend a good trans cooler and gauge. An EGT gauge would be good to have while towing also. It will let you know how hard you cn put your foot in it and for how long.

 

[towcat]

to the OP-
I have been towing in kali for the last 20 years. I can shed a little insight into your predicament.
first. your current combo is no good for towing. you will need a minimum of 4.10 gearing for the hills and overdrive to keep up with traffic on the flatlands. this is good for loads to 10k on the trailer and a gross combined of 18k/lbs.
if you're good with dropping a few gears when going up any hill, you can live with no turbo. *IF* you do turbo, an intercooler is manditory with kali hills. unlike the east coast, our hills are long and steep. ideally a wastegated turbo is best. Friends of mime fortunate enough to borrow my '92 F350, will report there isn't a hill the truck won't flatten easily and there is no need to glue your eyeball to the pyro.
for the sake of simplicity, my F450's operated with no turbo and routinely grossed 15k to 18k on the deck gross combined. stock gearing is 5.13. for a while, I played with 4.62 for faster unloaded intercept speeds. that ended with a monster of a speeding ticket. none of my F450's had a pyro and the only thing one had to monitor casually was the coolant temp gauge. only downside was you could walk as fast the truck climbing a hill. but in the end of the day, it's how much money you put in your pocket and not need to lay out for expenses.
if you want to hear more, let me know.