Cummins ISX Adjustable Fuel Pressure Harness

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What you are buying is an adjustable fuel pressure harness for a late 2003 to 2010 Cummins ISX engine that has/had the EGR or DPF.
If your engine has the DEF system this WILL NOT work.

It comes with a 10 position control knob that mounts in your cab and connects to a harness that is connected to your fuel pressure sensor.

It is 100% waterproof and designed to handle the underhood temperatures produced by your engine. Increases in power are adjustable from stock hp to 100 plus gain, Torque gains have been as high as 250 ft lbs.

This set up will increase your fuel mileage anywhere from .5 mpg to 1.75mpg. This harness will wake up your ISX and give that extra fuel mileage that is needed.

Harnesses are professionally built and tested before shipping. This product is made in the USA and carries a limited warranty. If for any reason you do not like the results, we offer a 100% money back guarantee. Simply return the product within 60 days for a full refund.

Contact us for more information and to see if other tuner options are available.

Diesel Freak, LLC is not affiliated with Cummins or the Cummins brand.

QUESTION: How Does it work?

ANSWER: One Harness will plug in between your factory fuel pressure sensor and your factory wiring. By plugging into the fuel pressure sensor we’re able to alter the sensor to the ECM, increasing the rail pressure from 20,000 psi to apx 22,000 psi, giving it a 10% increase in pressure. The second function is where the biggest part of the gain comes from. We adjust the engines injection pulse width, changing timing essentially. This increases horsepower, torque and fuel efficiency without causing any damage to your motor.

QUESTION: Will these harnesses effect the longevity or reliability of my engine?

ANSWER: No. We have never experienced an ill effect by running these harnesses on any motor. The factory has maximum parameters already programmed into your ECM on your engine. All we do is go to those max parameters. We cannot make it go past those. Your engine is still within the maximum allowable specs of your engine set by your factory.

QUESTION: Will this effect my engine warranty?

ANSWER: No. We are an ADD-ON after market product. To date after 15 years of service, we have not had a single warranty issue. If you do not want/like the product, just remove it and it leaves no trace or footprint on the engine or in the ECM.

QUESTION: How hard is it to install?

ANSWER: With every harness order you get detailed instructions sent along with a wiring diagram of your engine. The fixed harness typically takes 5 minutes. The adjustable harness could take up to an hour.

QUESTION: Will my engine run differently?

ANSWER: Yes it will. There will be no more turbo lag, virtually eliminated and your throttle response will be quick and crisp.

Diesel Freak, LLC is not affiliated with Cummins or the Cummins brand.

Additional information

Weight 1 lbs
Dimensions 13 × 10 × 1 in
Engine Year

2003.5, 2004, 2005, 2006, 2007, 2008, 2009, 2010