i have special tanks ;) the tag on them says, "150 gal US, 142 (I think) usable". Even when I'm totally empty I haven't been able to put more than 180 something gal of fuel in the both. The tanks look clean inside, so I don't know ... they're probably 120 gal, not 150. But 1500 mi without refueling? that's amazing. You probably did over 8 mpg.

Agreed. Definately would like more info on this as well. What effect does it have on the catalytic muffler, or do you remove that as well? It doesn't screw with the truck's ECM? I'd think the exhaust sniffers would be sending all kinds of warnings to the ECM.

With a cold engine (after it has been shutdown for 6-8 hrs) turn the key to the on position for about 15 seconds (do not start) let the egr close. Then simply unplug it..... Your ISX will run cooler and get better mpg.

Wouldn't that give a check engine light? Would you have to do this every time the truck is started?

It shouldn't, but it will throw a code. No harm no foul, but the engine needs to be out of warranty from Cummins. Make sure the connectors are taped and secured to keep out moisture and dirt.

Hmmmmmmmmmm, I think I might try this in the morning. What about you, Rev? You got an ISX you want to try it out on?

Thanks for the info. I will give it a try. Is anyone else running like this? I'm also about to hook up a hydrogen generator on my ISX. I have gained 1mpg with one on my Series 60 in my other truck. Well worth the $.

-scott

Well, I just tried it. Runs like a charm... bobtailing, anyway. We'll see in a week or so about fuel economy and power. I'm still concerned if there will be any shortening of the life of the catalytic muffler... I've heard they cost around $3000, though I've never had to replace one.

I do, but I'm still under warranty until next June.

I have been running with the EGR in "test mode" (unplugged) for some time now. My latest oil sample came back from the lab... a few points lower iron, lead, etc and WAY less soot... .2 in 25,000 miles without a bypass filter. Even the oil looks cleaner longer, visually. Even on a hot day with the AC on and under a good pull on a hill, the engine rarely exceeds 195F. Fan cycles way less than with the EGR plugged in. ECM shows a mpg average now in the high 7's, but actual pump to pump is averaging around 7.3-7.4 . Throws on fault code, but it just shows up as an electrical disconnect on the Cummins test software. Dealer could care less that the EGR is unplugged and is facinated how well it is working.