maxxforce 11 do not start

Ok, sounds like you have a Maxxforce DT, 9 or 10. The 11 series is the same as the 13 and they do not have ipr or icp sensors/regulators. If you have ServiceMaxx computer program you should be able to see fuel delivery pressure build up to at least 30 psi while cranking. Your ICP pressure should be over 700 psi to start the engine. Make sure you are not reading ICP desired because that is what the ECM is commanding. There is a schrader valve on the side of the intake manifold that looks exactly like a tire valve, this is where you need to bleed the air out of the fuel. Some engines have them at the front, others are at the middle area. Remove the cap, press in the center valve and use the hand primer. You should see fuel flowing out. Make sure it is all fuel, and not air. If there is air, keep priming until it comes clear. Make sure there is oil in the engine. Crank the engine and watch the gauges. You should see oil pressure come up and the tach needs to show some RPM, this confirms the oil pressure is working, and the ECM is seeing rpm. The biggest thing is going to be your fuel pressure. Make sure it is developing fuel pressure too.

 

I think all Maxxforce have the fuel pressure sensor. But you could also put the manual gauge on too. Good luck!

 

Remove the air filter and make sure nothing is in there, also check the exhaust pipe. How much fuel pressure is the engine making? How about the ICP pressure?

 

Ok, I know that this is a super old thread, but whenever i see advice from you, I usually respond on it because you're pretty spot on. Anyway, at one of my other shops, I am having a fuel issue on a Maxxforce DT EPA07. The tech there says the tractor will start and run, but after about 5 min, it starts to misfire and when you step on the acceleration pedal, you dont get good response. The laptop shows they are getting 58-60psi of fuel pressure and they are getting about 40psi on oil pressure. When they bleed the fuel system from the schrader valve, they do get air coming out the system. After they bleed the system, they start the truck and it runs great for about 5 min and then it starts to misfire and have the slow response from the acceleration pedal. When they bleed the system again, they get lot of air coming out again.

I researched this issue a little bit and some people pointed to the check valve on the fuel filter housing. I have yet to replace that valve, but I wanted to see what your input was on this. They recently replaced all 6 injectors in the past year. 3 of those injectors they replaced in the past week. When they replaced those 3 injectors, they replaced the high pressure oil rail o-rings and seals. They also replaced the ICP sensor on the rail. Any advice will help! Thanks.

 

What happens to the fuel pressure once it starts to stumble and die? I think you are looking at a base fuel pressure/supply issue.

 

So I just spoke to the mechanic and he says that he doesn't lose fuel pressure even when it is misfiring. He did remove the check valve fitting, cleaned it and put it back on and tested. Truck is still doing the same thing, but is now giving a code for cylinder 1 and cylinder 2 balance below min limit. They just replaced injectors 1, 2, 3 within the past week. Thoughts?