Questions to ISX owners

I would agree that "unhooking" the EGR, as in unplugging it, would do what you suggest. That is because you are causing the ECM to have a brain cramp over what you did. However, by blocking the EGR gasses from entering the intake, and leaving everything else hooked up, does not do this. Unlike Detroits, the ISX (at least pre 07) does not have a EGR gas flow sensor. If the EGR gasses are not flowing into the intake, yet all connections are hooked up, then no harm, no foul.

Either way, I have had a block at the intake preventing EGR gasses from going in for roughly 300,000 miles. I currently have almost 700,000 on the engine. The engine really cleaned up after I blocked off things. Now my oil stays almost from the jug clean up till around 10,000 miles. My oil samples at 25,000 OCI's look like a much younger engine. And with a year round average above 7mpg (just below 7 mpg average in winter, well above 7 mpg in summer) compared to the previous year round average of roughly 6.5, it was a no brainer. I haven't had the engine on a dyno, but I am competing quite favorably with others pulling the hills.

But now there is a better solution anyway.... a guy who used to work for Holset (you know... the turbo chargers) is now reprogramming ECM's to eliminate the EGR and DPF functions. Basically turns the ECM into a pre-egr ECM. And he cranks up the hp and torque. A complete reprogram, not a "add-on" box or some other goofy device. Do a web search for JBall Electronics.

 

Dangra, let me run my issues by you and maybe you can tell me what to try next. I have an 07 (pre-dpf) KW T800 with a ISX 475/1850 365K miles. I only get 30 PSI of boost pulling hard and 20 PSI when using the engine brake at 1800 rpm as you suggested. Changed the EGR a few months ago. I've had a tech run the EGR/Turbo test with the Cummins software and it checked out good. They only thing is when he ran it the first time it started to spool up the turbo and the the engine stumbled and shook and the test stopped. He said he had never seen that before. When he ran it again it ran ok. I checked the CAC and found two boots were leaking. I tightened them up and it held pressure fine. I checked the turbo actuator and it was leaking air. I changed it and the turbo controller as well. I can not find an exhaust leak in the manifold. I'm going to look again on saturday am when the engine is cold. The only check engine light I've had is low fuel pressure. It has only come on twice and both times it was a few days after I changed the fuel filters. The engine was idling (900 rpm) while I pumped off a load for about an hour. Then the CEL came on as I was pulling away from the customer. The two times this happened was about a month apart. I found three points on the fuel system where you can hook up a guage and check the pressure. The only thing is I'm not sure what the pressure is supposed to be there and at what RPM? Thank you for your input.
BTW I lived in Saskatoon for 3 years. I sure do not miss the winters. The Greek restaurants were good though!

 

As a Tech, what do you know about the Cummins Recon engines (re)made in Mexico. It's a genuine cummins recon, (2003 pre-egr) but I'm told they are all now made in Mexico. They do come with a 2 year 200,000 mile warrenty, but it will cost me $21,200 + install + tax. I'm not sure how many book hours are charged for a remove/replace on one of these. What is the probability this motor would go 1,000,000 miles? Did they get the cam issue resolved? Or should I expect to replace them around 700,000 miles?

 

I have a 2003 pre-egr ISX 475 ST in a 9400i with air tabs, FASS system, High Flow muffler and air filter, on Xone XDA Energy single tires. I've seen 9 mpg and for the last 8,712 miles have averaged 8.268 mpg. I don't use the truck computer, I check my mileage at every fill up. I run at 1300 rpm, which for me is 57 mph, and average about 70,000 lbs gross. Less than 100 miles per week are run mt. I didn't believe 9mpg when I first got it, I redid the numbers three times to verify, checked my tire revolutions per mile and had my speedometer checked. Everything checked out, I did get 9 mpg. My new goal is 10 mpg.

 

Hahahhahahah - get ready for overhaul, hopefully you saved that $ 25,000 in fuel - because you gonna need it. Whatta deal hahahhahah

 

Why would he need to get ready for an overhaul? I run my ISX around 1300-1350 most of the time. Puts me on about 60-62 mph. I currently have 778,000 on it and just had the bearings checked, high and low, when I had it in getting the overhead and some other stuff done. All looks good. Used oil samples look as good as when the truck had 300,000 miles on it. SilverEagle does beat me some in mpg. I average in the mid 7's.

 

Well, he says in another thread he got it to milion miles, which would make me withdraw my opinion to some extent. But I still believe that extreme fuel efficiency cuts the ISX engine lifespan. Anything below 1400 rpm when loaded is not recommended by Cummins itself. There is a reason for that

 

Actually, it's 1370 rpm that Cummins has published as the lowest recommended Cruise RPM. But I admit, that's really splitting hairs.

Anyway, Cummins didn't recommend low rpm Cruising for the N14 either. I have over 1.6 million on mine. Been driving it close to 1300 rpm for years. My point being that this isn't a "firm" recommendation to follow. I think it's more of a safe suggestion based on the "lowest common denominator"...essentially meaning some people don't exercise the best smarts in their maintenance practices and engine operation.

 

Whenever they are talking 1370 rpm its with light load or no load at all. which is the hint - a lot depends on the load on the engine, people who drive with 55 mph speed limits with 6,000 lbs load in the van sure can get away with it. I would never even try to keep 1300 rpm in top gear thru Wyoming hauling 40,000 lbs load. It is not right and I don't care about mpg. I'm not that broke to be wiling to trade my future for todays saving on fuel because I'm more concerned about my engine being up to task of retrofiting in 2014 - thats where true savings going to be: $150,000 in my pocket if I won't have to buy new truck. If I knew that dumping extra fuel in my motor would help it live longer - I would be more than glad to do it. Problem is I don't know it, so I stay where I think it is running the most effortlessly

But I agree with you, there is so many variables and ways to screw up motors - its hard to come up with general conclusions, not to mention there will always be someone succesfully doing oposite - like the guy with Volvo D16 625hp I talked to - he put 670k miles on it and still loved it when this thing is total failure and off the market for long time already

 

I agree with the amount of load you are carrying makes a difference. That was one of the main reasons to my the lowest common denominator comment. I am able to run light to medium weight loads on mostly level ground most of the time. Every once in a while I pull a load that runs close to gross. Those I usually bump up to 1400-1450 rpm to keep from beating up my bearings and any other stress on my engine.