2003 Peterbilt 565 ISX. How do I drive this thing?

I think you got it figured out. My part time boss has the same motor and it is a turd in low rpms. I had the hardest time with it empty because I usually short shift but that doesn't work.

 

On a long hard lug with a lot of weight if you wait till anything lower than 1300 on a downshift you will almost stall them out. An ISX will outpull both the 3406's (a,b,c, and e) and an n14 but you need to keep the rpms up. My 565 ISX's are the most powerful engines that I own but you need to keep above 1400 to find that out. For the record in my world a N14 is a dog at low RPMs too. Maybe its because ofthe 150,000 pound loads. The ISX's sweet spot is 1500 to 1800. Anything over 1800 and you are wasting your time and fuel. Never grab 2 gears. They don't have a long enough power band.

 

i used to drive a 06 with the 565 isx 18 speed. if that truck had wings.... it would pull right along 600 cats. with the 18 i normally ran it 13-1800 rpms let it pull down to 1350 before down shifting. up shift on a split about 16 full gear up shift at 18 also agree its not a good motor for skip shifting past the low side of the box. i ran pretty heavy in that truck almost never below 92k most the time i was pushing 110+k

 

Seeing as how somebody is putting down us yellow blooded folks, Cummins wouldn't know a proper operating fuel governor system if it hit them upside the head. They didn't have one in the mechanical days, and they for certain ain't got one on their ISX setup. When you move the electronic pedal the width of a dollar bill and go from 1700 rpms to low idle, yeah, just how do you drive one? Skip shift, scalp a few, and then you get the ISX cm 871 with the jerk off mode from about 35mph to 45 mph. They're governed alright, fully depressed or totally off the pedal, yeehaw. I wouldn't trade a picture of a good 6NZ for every ISX ever made, but that's my opinion of Cummins, and you know what they say about opinions. Sorry OP, for the interruption.

 

Above posters are correct isx loves higher rpm they make peak power at 1800rpm and hate low rpms when driven right there a beast and will walk the dog on cats,detriots and all of the other new motors.keep rpms in the 1400-1800 range.once you learn how to shift it you will appreciate the pulling power it has.

 

isx's take a little finesse on the fuel pedal to shift. you don't come off the throttle all the way like you do on a cat or Detroit. rpms drop off very quickly on the isx. makes it possible to make very quick shifts once your used to it.

btw i was not putting down cats i just stated that the 565 isx i used to drive would pull right along with 600 cats on the same loads. my truck at that company was the only pre dpf emissions truck they had with the isx instead of a cat. there dpf trucks were all isx's but mine was the only pre-07 emissions truck with the isx most the fleet was 550 acerts with a couple 600's that truck would pull pretty even with the 600's and out pull most all the 550's they did have one 6nz 550 that would pull me by about half a truck length by the end of a hard pull. the dpf isx's they had where 475-525hp and mine would walk on them.

again not putting down cats just stating what that particular truck would do, i drove it for a couple years.

 

I'm feeling the love here...LOL.

I just bought a 2000 W900L with a Signature 565 ISX. The main reason I went with this truck was that the engine was removed in 2006, sent up to Montreal and totally refurbished to the tune of $20K which I confirmed by calling the rebuilders myself and got the information first handedly. It went to Canada because of the exchange rate in the dollar at that time...was cheaper to have it done by Pepe' than by Peter evidently.

I'm having my share of issues with everything that a used truck with a million miles on the chassis would, but all to be expected and I am not complaining. My beef is with a few things with this ISX.

Number 1; EZRider hits the nail on the head with the finesse needed to drive an ISX or N-14 for that matter. They ain't no Cat at the throttle pedal, that's fo' sho'...I consider myself to be a fairly proficient shifter of many types of transmissions over 35 years of doing it...but these Cummins fuel governing systems will make a fool out of you no matter who you are. I am kicking myself in the butt daily since I put PB Blaster to the underside of the pedal and spring and roller. It's WAAAAAAAAY too sensitive to be doing that. Now I'm looking to install a secondary spring of some sorts to stiffen up the push a bit. Man, you can't touch that stinking pedal with 2 inch pounds of force without red-lining the tach it seems. A Cat's rpm's stays where you set the pedal; a Cummins heads off the dial every time. It ain't pretty some days.

Number 2; Engine brake. I have a problem with mine. We plugged into the diagnostics Friday and found that the switches work fine, so eliminate that. The Jake works on all 3 stages, but I'm not getting full power, so I'm missing at least 2 cylinders of efficiency. Yesterday I dumped $3,500.00 into this engine for #1 and #2 injectors, a Jake wiring harness, pan and valve cover gasket, pyrometer probe, and a bunch of little stuff with the intentions of finding and solving the Jake problem. After an oil change and all that, it's (engine brake) still not firing on all 6 cylinders.

I had it to a well-known shop in Connecticut Thursday that had the cover off diag'ing this problem, and they claimed they witnessed "aerated oil" at the jake spools. Thay also said they couldn't fix it today. That was a waste of time, money and mileage. I could have went to the Volkswagen dealer and have them tell me the truck's broke, and we can't fix it...

I cut my losses there and went to my favorite shop in New Hampshire where we all concluded after a laptop diag, we needed to have 2 injectors and the oil changed, etc. I thought we'd correct this jake issue, but it's still not fixed.

Has anyone else ever encountered a similar issue with a "not-fully-functional" engine brake on an ISX, and if so, what did you come up with for a problem? This aerated oil statement didn't seem to make sense to me, as the oil presure was always normal. WE even pulled the pump and pickup tube and re-sealed it. Nothing visually wrong from the pickup tube back.

On a positive note, this engine pulls like a locomotive. Even with those 2 bad injectors. When it gets straightened out, look out Mr. Yellow Motor Man...lol.

 

We'll be looking out, but it's a three step process. First is left turn indicator, second is right turn indicator, and third is mirrors.....lol.