I accidently make more pep or power by replacing a fuel line.

Last week, a fuel leak started that morning from the check valve/fuel line on the back of the injection pump. I figured a line worked loose so keep driving. Later, it got worse, spraying fuel all over the motor and started missing.

I got home loosed and tried to tighten the line, it broke!!! I ordered a new one from Freightliner. While taking off the fuel line fitting off the check valve, the check valve loosen from the pump and fell down on the ground!!!

I lost the check valve spring. I took another line and check valve off to identify the spring. The local hardware had one except it was 1/16 of inch longer. I used it anyway, reinstalled all the lines started it and took it for a test drive, WOW!!! Something had happened,,,, MORE POWER!!!!

I'm guessing the line was twisted or kinked were it broke and restricted fuel to that cylinder. OR.......... That spring is letting more fuel to pass to the injector.

What do you think, I thought about changing the rest of the check valve springs with the same spring (the tension must be different) to see the difference.

Tomorrow at work I'm borrowing a pyrometer gun and check the exhaust manifold at each cylinder especially the cylinder with the differnt spring to see if it runs hotter.

 

If you are talking about the delivery valves at the back of the pump, then you are probably dumping more fuel into that cylinder due to the different spring. Keep us posted on what you find.

 

Cool! I'm guessing that the new spring has a different stiffness to it. It must be allowing the delivery valve to stay open for a longer period of time or travel further outward from the holder. Keep us updated if you decide to switch all of the springs out.

 

From what I understand when an injector goes bad it leaks letting too much fuel in to the cylinder sometimes it burns a piston. You could be doing something similar with your tinkering... be careful

 

I know I'm getting more fuel because the idle is higher. I also notice the MPG is better than usual. I'm very happy with the pep right now.
Before I change the other springs I going to reseach and find all the specs on the factory springs and compare the current spring I installed.
I also want to monitor the cylinder temp on that cylinder and compare it to other cylinder temp. I want to make sure it isn't too hot like DJ mentioned.

I'll keep you guys posted.

 

I may be totally off base, but here it goes... Just because you add more fuel doenst mean it's going to "leak" into the cylinder. The injectors are going to atomize the fuel unless the injectors is weak or bad like DJ mentioned. All you are doing is allowing more fuel to be atomized for a longer period of time.
I have messed with the delivery valves before and didnt find a whole lot of power out of them. Just dont make a huge difference in our trucks like they do in the p-pump trucks, but I'm real interested to hear about your results.

 

Cody is right. A different spring would be the equivelant of advancing or retarding the timing.