Questions to ISX owners

ex-white Swedish Vacuum cleaner hahahah - okay seriously if the rest of the world could figure out how to build a sleeper and a cab I'd be game for something different. Is it so wrong to be able to see out of the cab, and stand up straight when you get outta the seat?!

At any rate to go back to this limiting malarky that's going on - I've had GDP (gear down protection) turned off since about 2 months after I bought this truck. The fleet before me had 11th locked at 60mph - making the top 2 gears completely worthless......

The limiting is some weird stuff - seems to limit my rpm at random points - usually when I'm trying to run up speed on a short downhill to upshift and start a climb. It'll lock it down to 1500rpm and then by the time I clutch to upshift in reflex it's too late. The next time it's in the shop (returning to the place after this run) I'm having them unlock anything that even sounds like a limiter - I'm sick of this crap!! What part of Owner/Operator doesn't Cummins understand?!

 

No kidding. The fleet I drive for has Volvo VN's mostly with ISX 450hp engines and few with the volvo D12 465 . The trucks are speced exactly the same other than the engines. Loaded the same the ISX's can pull a small gap on the volvo engine from a dead stop. On a long pull the D12 will walk away a bit. Cummins just figured out how to make you think their engine is pulling hard with all that noise and vibration.

 

Umm I have to disagree. The EGR cooler will not get any hotter that ambient exhaust temp. It also will not have anymore pressure than the rest of the system at any time.

But it won't cool off as fast as it might. Not sure how much slower, just that it might be a little slower.

 

Aside from Smart-Torque (for Stupid-Truckers), Gear-Protection (for Truckstop-Racers), Load-Based-Speed-Control (I have no clue what is this for) - there was also 1450 torque, 15 liter variant called ISX-For-Dummies

 

the lower power settings level off early in the rpm range also..

solution, more power

 

I think keeping EGR-cooler sealed by EGR-Valve stuck in closed position would prevent hot exhaust from entering the very EGR-cooler. But maybe I'm wrong and diesel engine exhaust is cold and has no pressure. Perhaps it has characteristics of penguin fart

 

I've been trying to figure this EGR system out in my spare time - apparently it gets complex when you try to feed the horse his own crap.....

Basically blocking off the EGR valve won't harm a thing as far as I can tell. Here's the way the system works IMO so far (no expert here yet):

Engine burns fuel/air mix - exhaust valve opens - exhausted into the manifold and turbo spool. Some exhaust enters the EGR cooler, passes through, cools -

IF EGR VALVE IS OPEN - cooled exhaust gases re-enter airstream of turbo intake path.

IF EGR VALVE IS CLOSED (temporarily or permanently) - the exhaust stays in the EGR cooler, no harm no foul (and no crap-eating horse). It can't overpressurize because nothing is forcing it besides more exhaust with another path (path of least resistance wins), and it can't superheat because it's.... well..... exhaust and supposed to be hot in the first place. The exhaust will likely be somewhat cooler with the EGR blocked in theory - that's the whole idea - a crazy hot burn (tough on an engine) to burn off the NOx.

 

I have never, in my time in this truck, been outpulled by a Volvo D12. As far as identical loads - nope - I'm always pulling 80k or as near as I can get. That was with the engine at 475HP/1650 - now at 550HP they're getting in my way all the time - or maybe they're just fleet limited trucks.... hmmmm

OR MAYBE the laws of physics are totally wrong and somehow a 12 Liter Volvo engine can outpull a 15 Liter Cummins - yeah that could happen. Only it never does! Maybe all those fleet drivers just like babying their trucks up every climb 10 to 15mph slower than me. While we're at it - let's ask ourselves why Volvo went to Cummins for an engine in the first place before they came up with their D16 (which had serious issues).

Sometime very soon, I'll overcome the truck ordering moron that ordered this truck with a 16 series 13 speed - and get all 1850ft/lbs out of this motor (without breaking gears). btw - The Smart Torque is to keep 6,000ft/lbs of torque from twisting a driveshaft in half like a tootsie roll. The difference in the 2 torque ratings is nothing but heat treated gears and maybe bearings and oiling - but so far I can only confirm the gears side of it.

On the Volvo side of the fence - they seem to be into their brakes an awful lot while I'm passing them at 70mph on a 5% grade...... so I'm guessing they probably don't have 600HP of jakes either. Just saying - your company Volvo hack can't outpull mine - they've brain damaged yours at the shop.

 

For the people with a isx you can improve the performce by removing the tube going into the air intake i tryed this an it pulls better an MPGs is up

 

Im not sure if you are aware of this, but the Engine brakes tell you alot about your egr and turbo performance. No 3 position on you EB is the activaton of the turbo boost for added brake HP. If you are not getting 30 psi at 1800 rpm with the EB, there is something wrong with your turbo activation process. There are numerous possibilities where this is concerned. Un hooking the egr makes the engine more efficient, but makes the drivability worse, as there is less boost at lower rpms requiring more throttle to run up the engine. This might be ok with an auto shift, but makes shifting harder with a standard and requires more throttle at cruising speed. My point is, it isnt perfect, but it cures the hot EG being piped into the intake under load. Something is wrong when this is going on, as the EGR is supossed to closed under load, open when there is deceleration and moderate load etc. I suspect there is a calibration issue that needs to be addressed yet by Cummins, the problem is that when there are no codes other than the typical open/closed circuits, sensor higher or lower than normal, there is no way for the new techs to assume a possible anomaly based on the performance rather than replacing parts while they run down the troubleshooting tree. This is why there is little help in the way of this EGR battle. Most EGR valves are being relaced when they are not the problem, they are acting commands from the ecm which is getting its info from sensors which are not addressing issues, just making the engine do things it shouldn't. I have found a lot of help, checking the air to air exchangers for leaks. I am always interested in finding out what everyone else is experiencing. I hope this is helpful.