Had a problem with my 6NZ with the pressure at 50psi at idle. Went to CAT and they replace the spring. It jumped to 90psi. My problem was no power. Well $62,000 later it was combustion exhaust in my coolant. Cylinders 4, and 5 let go. Also my engine had a aftermarket head. Now it's back to a beast of a truck.. Good luck with yours.
Looks like you have a modified MBN. First thing I would do is remove the by-pass hose off the fuel return back to the fuel transfer pump. Get two number six JIC caps and take that POS hose off. Any air coming out the return is going back into the engine. You have a 75 LB regulator in the fuel filter base under the fuel return line. I have heard people using the 100 LB regulator off a SDP. All I do is take the 75 LB regulator out. Take it apart and give the spring a little stretch. Do not over torque the return check valve. You want your fuel psi around 95 psi under load. Also the fuel return line off the back of the head. On ACERT engines Cat came out with up-dated brackets. I put them on everything. Have not seen a hose bust yet. When replacing that line, remove the fitting out of the filter base and put it in the back of the head. Take the head fitting and put it in the filter base. Turn your hose around and put the ninety degree elbow on the head and use it to get your angle. Get this from your Cat dealer about the fuel line brackets, SEBD6842. If you put this set up on I use a 1293172 stud in the rear cover bracket. A lot easier to put the rear support on. Also on ACERT engines Cat updated the air compressor coolant line from the cylinder block to the air compressor. When you replace your hose take the old one to a Cat hose shop and have them make it out of the ACERT material, same length of your current hose. You will need part number off the ACERT hose, because the hose shop will not know what your talking about, 3217384. Remove the hand priming pump and put a 6N4414 cover and a 1P0436 gasket. Keep a few 1P0436 gasket in your truck with the pump. Your wearing the check valves out in your pump. You only need it to prime the fuel system if your out of fuel or fuel filter change. Which most people pre-fill the filter. If you do, pour the fuel in the little holes. The big hole is unfiltered fuel and it's damaging your injectors. When you replace your thermostats part number of the by pass hose is a 9Y4104. I use a 7E0759, it is cheaper and longer.
The new fuel pressure spring they sell 339-4983 is shorter than the older 339-4983 strange i have the longer one and wanted to have a spare and the size was different
I had the same issue and it drove me insane. I had a small stumble running uphills loaded, I replaced the entire fuel system lol seems like It turned to be the dem IVA pressure sensor on the front
I’m having the same issue. So I changed fuel pressure regulator on secondary filter ( return side) and still nothing. I’m guessing now I need to chase fuel lines now smh
@@JoseRamirez-wb1vq anything to help!! I was like that too.. just bought a generic heavy duty diesel fuel gauge to measure the pressure and the coupler was too small. A friend of mine finally told me he had the same issue until he found the coupler.
I just did the spring went from 80psi at 1500rpm to 110psi.. truck running a lot smoother now too.
Had a problem with my 6NZ with the pressure at 50psi at idle. Went to CAT and they replace the spring. It jumped to 90psi. My problem was no power. Well $62,000 later it was combustion exhaust in my coolant. Cylinders 4, and 5 let go. Also my engine had a aftermarket head. Now it's back to a beast of a truck.. Good luck with yours.
Como se comportaba el motor a bajo rpm?
Also, the fuel pressure regulator can twist off and you can stretch out the spring and it will give you more psi
Looks like you have a modified MBN. First thing I would do is remove the by-pass hose off the fuel return back to the fuel transfer pump. Get two number six JIC caps and take that POS hose off. Any air coming out the return is going back into the engine. You have a 75 LB regulator in the fuel filter base under the fuel return line. I have heard people using the 100 LB regulator off a SDP. All I do is take the 75 LB regulator out. Take it apart and give the spring a little stretch. Do not over torque the return check valve. You want your fuel psi around 95 psi under load. Also the fuel return line off the back of the head. On ACERT engines Cat came out with up-dated brackets. I put them on everything. Have not seen a hose bust yet. When replacing that line, remove the fitting out of the filter base and put it in the back of the head. Take the head fitting and put it in the filter base. Turn your hose around and put the ninety degree elbow on the head and use it to get your angle. Get this from your Cat dealer about the fuel line brackets, SEBD6842. If you put this set up on I use a 1293172 stud in the rear cover bracket. A lot easier to put the rear support on. Also on ACERT engines Cat updated the air compressor coolant line from the cylinder block to the air compressor. When you replace your hose take the old one to a Cat hose shop and have them make it out of the ACERT material, same length of your current hose. You will need part number off the ACERT hose, because the hose shop will not know what your talking about, 3217384. Remove the hand priming pump and put a 6N4414 cover and a 1P0436 gasket. Keep a few 1P0436 gasket in your truck with the pump. Your wearing the check valves out in your pump. You only need it to prime the fuel system if your out of fuel or fuel filter change. Which most people pre-fill the filter. If you do, pour the fuel in the little holes. The big hole is unfiltered fuel and it's damaging your injectors. When you replace your thermostats part number of the by pass hose is a 9Y4104. I use a 7E0759, it is cheaper and longer.
Bro. You are very knowledgeable. Thanks for the info.
Tengo un cat c-15 es inestable a bajo rpm que pudiera ser?
Fuel pressure doesn’t normally drop to zero right away after shutdown when measuring at the filtered port.
Run the CAT fuel filter. The after market filters are not up to CAT specifications for the fuel system....
Nice find on the spring kit.
Would be interested if you find upgraded part numbers for the check valves in the filter head by the rail.
Tyanks for the information... That maybe my problem. I will order that spring upgrade. Thanks again 👏
The new fuel pressure spring they sell 339-4983 is shorter than the older 339-4983 strange i have the longer one and wanted to have a spare and the size was different
More videos with the rig please -interior and exterior video and shifting would be great ❤
Put the old cap on there. It's longer than the new one and will give you more pressure.
Exactly. Easiest increase of pressure
I had the same issue and it drove me insane. I had a small stumble running uphills loaded, I replaced the entire fuel system lol seems like
It turned to be the dem IVA pressure sensor on the front
Probably would’ve seen if you could’ve used the taller Allen Head on the longer Spring for Pressure Increase.
u can buy a 304 9385 pressure relief valve that is fitted to c15 acert sdp ,,,,, that will help improve fuel pressure
I’m having the same issue. So I changed fuel pressure regulator on secondary filter ( return side) and still nothing. I’m guessing now I need to chase fuel lines now smh
$90.00 for a spring? Yeah I want a CAT.
The outside gauge is correct and in-spec. At idle should be between 75 and 80, under load 90-100….. that’s per CAT.🏴☠️
Did you have tu updated filters? Because my filter light comes on now .. almost like there is too much restriction in the filter
Like to know if you ever got it figured out I dealing with same issues
What is the fuel pressure gauge part no
Please can you share spring dimensions ? Length and Diameter
did you end up changing the transfer pump to fix the problem
Miss. Trust me. You don't want 100 psi fuel pressure at idle. That would be catastrophic.
good video 👍
How does it drive under load?
Does it effect fuel mileage
Nice!
You can buy it for a dollar in asia
Can someone pls tell me what is needed to make a fuel pressure gauge like the one on the filter base like part names thanks in advance
You need to get the coupler from cat or if you can find it cheaper. Part #6v-4144.. and you can just get any gauge to plug at the other end.
@@truckingwithsal thank you so much I’ve been breaking my skull trying to put one on my truck
@@JoseRamirez-wb1vq anything to help!! I was like that too.. just bought a generic heavy duty diesel fuel gauge to measure the pressure and the coupler was too small. A friend of mine finally told me he had the same issue until he found the coupler.
Your hand priming pump could be bad too.
Mi cat c-15 es inestable en baja rpm que pudiera ser?
Anything more helps lol. Ull get it right n no time.
You don’t know who you bought the truck from ??? du du du