2009 ISX435 ST Emission Issues

I'm the brother of the truck in question and I have to say, I hate this motor! This go around resulted in a new turbo, oil pressure sensor, exhaust pressure sensor, and some pigtail wires. The truck is running worse than it did before this "fix". (Yes) the repairs have all occured at actual Cummins dealers. I've been everywhere from Las Vegas, NV, Bloomington, CA, West Plains, MO, Tulsa, OK, and Harrisburg, PA. I have spoken to the Cummins Care people and been told to have the Aftertreatment Efficiency Communication and Static Injection Timing tested and the dealers keep telling me that they do not know what I am talking about. They have told me that my truck is running perfect, but it dives in between gears when shifting up, has no top end boost (and it is a smart torque motor), and my fuel mileage is averaging 5.3 mpg. My loads have not been above 30,000 lbs since buying this truck. I'm ready to sell the truck for what I owe as I just want to get out of it that bad.

 

Another satisfied Cummin's customer! ;P

 

I'm sorry to hear that. The Static injection timing is a complicated procedure that is still somewhat new for ISX's to ensure the cam timing is correct in relation to piston position. Not everyone knows how to perform that procedure. It would be best to just call around and ask them if they know how to perform that. Hopefully you find one sooner than later. We have done several and it does make decent improvements.

 

I am writing to ask about the wiring harness for this truck. Since the Tulsa "fix" I have made a successful run from CA to OK and back from MO to CA. The turbo is only reaching a max boost of 12 pounds in the lower gears (5th and below) and maxes out at 32 pounds in the top gears. While driving up hill (with cruise control on) the turbo drops 10 pounds and immediately goes back up. When going down hill (with the cruise control on) it is boosting to 15 pounds and the Jake brake will kick in. There is a thumping that I can feel in the accelerator like a ball ping hammer thumping on my foot the whole time I am driving. Is it possible for wires to be bad at the injectors and cause this thing to drive like an injector is sticking or is it possible for the wiring harness to be bad without coding? That seems to be the only thing we have not changed at this point in time. Should the turbo speed sensor have been changed with the new turbo that was put on? Is it possible for the new EGR valve to be bad? I am tired of throughing money at this thing, but don't have a choice because we have payments and it is our only income.

 

Injectors are 100% mechanical. No wires to them. Only engine brake solenoids have wires under the rocker cover. It is possible for a bad injector to be causing this. The turbo speed sensor is pretty basic, as long as it works, nothing to worry about there.

 

Thank you Heavyd! You have been more helpful than any of the Cummins dealers around here! I have been told over and over again to just get used to it cause this is how this motor runs. Thump and all. As long as it is running, I am going to stay on the road. I have spent so much I could have paid off the truck by now. I need to recoupe now and pray that it stay running...

 

I believe that the injectors are electriclly controled. There is a cam that runs them. All it does is help boost the injection pressure of the injectors. The ecm controls the timing of the injection with the wires.

 

NO! on a cummins isx the injectors, as heavyD said, are 100% mechanical. you have 2 camshafts, 1 moves all the exhaust/intake/jake rocker arms and the other cam controls the injector rocker arms. only the jake solenoids have a wiring harness. and the timing of both cams is gear drivin in the front timing cover with a geartrain from the crank, all mechnical.

 

I have found that there are different types of ISX engines and it depends on the engine as to whether the injectors are electronic or mechanic. Our motor is a CM870 and therefore mechanical injectors. The ECM controls the timing of the Timing and Metering solenoids. The turbo has an accuator on it that is electric and the EGR has an electronic valve. There are some motors that are single cam and others that are dual cam, if I understand it correctly this makes the difference of electronic and mechanical. I think this is why there is so much confussion of how to fix this motor!!!

 

The injectors on an ISX work pretty much the same way that the injectors on a CAT or Detroit do...except the solenoids that control the fuel for metering and timing are on the outside of the engine instead of attached directly to the injector. Also, one timing/metering solenoid controls 3 injectors. The front metering and timing actuators supply the front 3 injectors, and the rear metering/timing actuators supply the rear 3 injector. Now, the injectors themselves are 100%mechanical. No electronics whatsoever on them. Timing is accomplished by an actuator supplying a precise amount of fuel to fill a void in the injector body between the upper and lower plungers, which determines when the plunger actually starts compressing/injecting the fuel. Metering is accomplished by simply determining how much fuel is allowed into the injector for use by the engine. They have been this way from the first ISX's up to the 2007 emission standard engines. I'm not that familiar with the 2010 emission engines, so I can't say for sure.