Adjusting Fuel Pressure

[01SMOKINSD]

Does anyone know where I can find the kit for shimming the fuel pressure regulator? I found one kit that was available through Diesel Innovations, I think the kit was around $40. If I am reading this correctly it should do exactly what the 18K mod does, but is not changable on the fly. Correct?? If Im understanding this wrong please correct me. Thanks!!

[Ramsmoker]

You are correct. The 18K mod runs the HPOP pressure up to help atomization. The regulator shim is to raise the supply pressure to the injectors. My view is to have both for sure.

[RJacks258]

How do you do this pump shimming I am reading about? Whats involved, timewise, costwise, and location? What will it do as far as performance and technical? Please help!

[Ramsmoker]

The work is easy, or thats because i've done it a few times. There are a few ways to do this. The results are the same in the end. Looking in from the front, With a 13mm deep socket, take the plastic cover off the top of the HPOP. You will now see the fuel filter housing, it's round. The line on your right is the return line and houses the pressure relief valve. You don't have to remove the line but do loosen it. This will take a 15mm wrench. You should at this point put a shop rag or two under this line and around back of the filter housing. With a long extension like a 30" and a #25 torx tip, take the two screws out of the regulator housing. Ease it off a whatching not lose any parts like the O ring or brass plunger. Remove the spring, this is where things will differ depending who you talk with. I use a #6 machine screw. Flaten the head down about half way and take the diameter of the screw down to that of the spring. This way you can turn it out if you need to raise the pressure more. Reassemble this relief an now move on to the gauge. Just around the back of the filter housing there is a flat plug an I can't remember the size off hand but this is where the gauge will hook up. In the back there is also a drain valve to let some fuel out before you pull the plug or you can remove the fuel filter to drop the level below the plug. You will have to match a fitting to what ever gauge you have. I would set the pressure no higher than 75psi. This mo will change the sound of your engine and increase thottle sensitivity. Feels like more power but I havn't seen proof of that. just smoother from added fuel delivery to the injector. I don't know your skill level or tool selection an how far away the parts store is but you should be done inside of two hours.

[Klutch]

Those are not the ame thing at all. The one bumps your fuel pressure up. The other tricks the pcm into having the hpop supply more hpo.

[RJacks258]

Ramsmoker------
The machine screw, what exactly are you doing with it? Are you putting back with everything you took out? Or are you replace something else with the screw? I think I understand most of it. Would it be safe to do this without a fuel pressure gauge? I'm just trying to get all the details first, I like to go over the process of things a million times in my head first before I go through with them. Thanks

[Ramsmoker]

First off, Do not do this without a gauge. This is not a science and every truck will be a little different. I'm sorry about my directions, let me see if I can clear this up. The modified screw is twisted into the end of the spring and is inserted into the brass plunger. This way you can twist it out to fine tune the pressure. Some people use #4 stanless washers and I'm not to shure about why because the fuel lines are steel and break down inside anyway. Hey, I'm with you. I have to get the motion picture in my head before pick up the tool's. This is worth doing and so is the cross over line between the hp oil galley's in the heads. There are links with pictures on most all mod's for the powerstroke. If you use the sites search you most likely will find what you need.

[01SMOKINSD]

Thanks for all the replys guys. The fuel pressure mod and the cross over line mod wont actually increase power but rather make the truck start and run smoother, correct?? The 18K mod will add power though if im understanding this right. Does anyone know where the fuel pressure is set stock from the factory?? Thanks everyone. This is by far the most helpful site ive found!!

[Ramsmoker]

You are correct. These do increase drivability. So does the 18K mod. The 18K mod raises the oil pressure to the injectors and the shimming increases the fuel delivery pressure to the injectors. Supply pressure is between 53 and 58psi on the trucks I've worked on. The HPOP I believe is 3000psi but Marc is more qualified to answer this.

[00powerstrokin]

what is the 18k mod?