Realistic Hauling Expectations

[6.5Dualler]

Hello all,

I am new to this forum but have previously gleaned very useful repair information from the wisdom of the forum members. I am new to the 6.5 world and diesel for that matter. I had a few questions about how the 6.5l hauls in mostly stock configuration. Let me explain my situation.
When the truck is empty I feel like it has decent get up and go power but the other day I was hauling about 4200 pounds of gravel in the flat bed and it seemed like it didn't want to move with any gusto. It was definitely driveable and did not get above 200 on the ECT guage. I have a small mountain I have to climb to get to my place and it seemed like it was struggling to break 35 mph. I would say the grade is between 6 - 10%. Is this normal for a stock 6.5l or could this be due to possible fuel supply issues. I can hear my pump running and I have done the engine running t-valve test and it continues to run fine with a steady stream of diesel out of the valve. The truck has about 109,000 and the original injectors. Injection pump was replaced under warranty before i got the truck. Any illumination on the matter would be greatly appreciated. Thanks.

[Robyn]

Hi

I'm gonna speculate that you are running about 12000# loaded.

A 10% grade is gonna kick the old girls butt hard with a stock set up.

The 6.5 is simply NOT a DURAMAX with 400+ HP and 900 Ft lbs of Torque.

A well blessed 6.5 can handle 300 to 325 hp and about 400 to 450 lbs of torque AND LIVE if the EGT'S are kept below 1000 F at the ports

Factory setting are about 210 horse and 380 ft lbs.

You may have about 1/2 the grunt of a late model DMAX. (Torque is not quite half)

But if you're kind to the little engine that could it will gitterdone.

GEARS MAN GEARS...USE EM. ;)

[6.5Dualler]

Thank you for your help. I had suspicions it was just a big haul for the IDI but wanted to make sure. Guess it is time for some upgrades.

[More Power]

https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=4476&stc=1&d=1572457650
https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=4477&stc=1&d=1572457650
https://www.thedieselpageforums.com/tdpforum/attachment.php?attachmentid=4478&stc=1&d=1572457650
https://www.thedieselpageforums.com/tdpforum/picture.php?albumid=64&pictureid=398

Installing a boost pressure and EGT gauge would be a good place to start, to know whether everything is OK and operating normally. Otherwise, yes, the above pics show that the 6.5L Diesel is capable.

Jim

[6.5Dualler]

Thanks for the insight. I have a boost guage installed. EGT is on the list. My boost pegged out at 5 psi all the way up the hill. I like seeing those pictures makes me realize that the 6.5 just needs waking up a little to do some hauling.

[arveetek]

Thanks for the insight. I have a boost guage installed. EGT is on the list. My boost pegged out at 5 psi all the way up the hill. I like seeing those pictures makes me realize that the 6.5 just needs waking up a little to do some hauling.

5 psi is definitely low. It should max out around 10 - 12 psi under full load if it is all stock. It may very likely have a boost control issue, or it could be going into limp mode which causes it pull back on fuel.

Did you have a check engine light on when pulling the grade at 5 psi? How much black smoke did you have?

If the computer was giving full fuel, at 5 psi there should have been a LOT of black smoke coming out the tailpipe. If there was little smoke, it's likely the computer was not allowing "full throttle."

Casey

[6.5Dualler]

No black smoke that I saw and I was about 3/4 throttle all the way up. No check engine light or any other warning lights. Could it be an issue with the wastegate solenoid? I checked the vac lines and they seem ok and no leaks from my stock crossover pipe. Even when I run unloaded and at full throttle I still am only getting 6 psi max for boost. It's an F code L65 engine with no EGR and a full 3in exhaust.

[6.5Dualler]

Still trying to figure out the boost issue. Hauled another load of gravel today and it felt weaker than the day before. I did replace my factory vaccum lines which fell apart as soon as I touched them. Now I see spikes of almost 7psi of boost. Still no black smoke or check engine light? What would have the computer prevent full throttle? I have been considering it being something in the fuel system. Not sure when the tank sock was last changed. Is it worth it to go to a pre-lift pump filter?

[arveetek]

Has the fuel filter been replaced recently? Sounds like the engine is not reaching full power. I don't think it's an ECM issue, otherwise it would suddenly feel like it lost a lot of power accompanied with a check engine light, and it would run weak until restarting the engine again. Lack of smoke, low boost PSI, and low power all point to fuel delivery issue.

Casey

[6.5Dualler]

Thanks for the reply. Fuel filter was changed about 2k miles ago. The fuel pump sounds strong and the truck feels like it has good power unloaded. I guess I need to change the fuel sock or just go with the pre-LP filter setup to eliminate that end. Other than that I am at a loss because I get no black smoke or check engine light at anytime.

[JohnC]

I guess I need to change the fuel sock or just go with the pre-LP filter setup to eliminate that end.

Just plumb the fuel filter drain line into a jar, start the engine and open the valve. See how long it takes to pump a pint of fuel. I think there's a spec, but I'm guessing 30 seconds is a good number. If it takes longer than a minute you may have a fuel delivery issue.