Does anyone out there have any idea what a stock V10's fuel pressure is suppose to be at idle?

 

35-39 psi
193- 310 kpa engine running
210 -310 engine off/ key on
Rich

 

Is it really that high? I have a supercharger on mine and I'm only seeing 27 psi at idle. According to the techs at Kenne Bell I'm suppose to have between 33 and 35 psi at idle. I'm running 7 lbs of boost and supposedly I should be seeing about 47 psi at WOT but I'm only getting 42. I've tried everything short of disconnecting the lines at the fuel rail and gas tank and blowing air through them to check for any obstructions. I've replaced the fuel pump, fuel pressure regulator and I change the fuel filter every time I change the oil. With all of that done fuel pressure did not change. I'm at the point of giving up.

 

Are you using a stock fuel pressure ? Have you tried an adjustable one aftermarket.
This is with your supercharger setup?Right ? factory stock ones use the vacum to adjust ,with the supercharger on there the vacum is less to the vacum side of the regulator therefore fuel pressure will be down on the high end.Yoou problably know this though.Did you ever find a fuel pump to fed this thing????
Rich

 

The fuel pressure regulator is hooked up to the boost side of the blower. I searched and searched for an adjustable regulator but there are no direct replacements. Plenty of adjustable regulators to be had but they would require some extensive modification to the fuel rail. I ended up replacing the fuel pump with a stock OEM unit which the techs at KB tell me is sufficient. What I don't understand is that KB tells me that their shop vehicle (Excursion V10) is producing the pressures that I reported earlier in the thread. I basically have the same exact setup and no matter what I try I can't get it to produce anymore pressure. KB has no idea what's wrong nor do they have any suggestions what to try next. They did mention something about pinching off the return line to the gas tank but I don't know about that. Have you ever heard of such a thing. It sounds like it would work but is it safe is my question.

 

I just don't see where you get the idea that a variable fuel regulator requires "extensive" modification.

Do you have a too lean condition under boost? If so you need to adjust the pressure. If not then what is your concern?

Fix is easy once you have reliable idea of actual pressure: An adjustable regulator (assuming your OEM pump can supply the pressure AT VOLUME)

I would test the WOT pressure before and after the regulator to see if your reported 42PSI is the "regulated" pressure, and not simply the max your pump is delivering

Several folks here have looked up all this for you, posted links, and made reliable recommendations on brand they had luck with.

Adapting a fuel regulator to the Ford fuel rail is not hard (IMO)

Contact any speed shop that modifies 5.4L Ford mustang motors and they will school you on the exact regulator that is easiest, what adapters, and any mechanical issues that are involved (location, Clarence).

 

The only reason I'm am concerned about fuel pressure is because the folks that designed and produces the blower kit (KB) is telling me what pressures I should be seeing. The reason I called KB in the first place is because I have a slight knocking under WOT and they seem to think that the problem is fuel delivery, volume or pressure or both. I appreciate the recommendations I've been given but none of them are from people who have actually done this on a V10 fuel rail. I don't believe that it is as easy as some may think. I'm being told it's not hard to do but no one is telling me how to do it. Believe me, I consider myself to be pretty well mechanically inclined and if there is a way to get it done I'll do it, all I need is a little guidance on where to start. What I don't need is to be told that it can be done and not be told how to do it. Sorry if I sound a little upset, this whole fuel pressure thing has just really got me pi$$ed. Crimping the return line in a sense would do the same thing as an adjustable regulator. It will restrict the flow and the amount of fuel going back to the tank which should increase the pressure, in theory anyway. The only draw back is that once the line is crimped you can't uncrimp it. What is your thoughts on this?

 

Google

"Fuel regulator".... over 5 million hits

did a easy "Search within results" for "install"... over 1 million hits

First hit: http://neptune.spacebears.com/cars/stories/fuelreg.html

You never seem to answer any of my direct questions on this subject

You have posted this problem in at least three different threads on this forum

You always seem to sound frustrated or take offense at the answers

You don't seem to do any more research then asking here

You wrongly assume any of us has ever needed to put on a fuel pressure regulator on a Ford 2v V10 and should share with you exact steps

You claim good mechanical ability

Hint... the reason there are over 35 different adjustable fuel regulators that fit Ford modular motors is that it is a necessary part of tuning the fuel air mixture beyond the factory EPA controlled fixed system.

Tuning a turbo charged or blower inducted motor is an art. One needs to know the air fuel mix during certain conditions... I am old skool and learned to do this by reading spark plug colors from runs on a back road. Later we got new fangled fast response O2 sensors and gages and access to chassis dynos and could do it from the cab of the vehicle

Stop getting pissed off, some of us are spending the time and effort to help you... perhaps only because a blown V10 is cool enough to ignore your attitude

 

Fred ,you was alittle harsh maybe.
I understand where your coming from.we try to help alot of people and never really hear back sometimes .
I know nothing about superchargers or blowers.But I do alot of research on things and the info is out there.The internet is very powerful in many ways.
I guess what I'm trying to say is as you know judging ones emotions in how they write is difficult sometimes.

We can only lead them to the water ,we can't make them drink

Rich

 

Fred, first off, I don't have an attitude. If I came across that way I apologize. I must be using a different internet than you because when I do a google search I don't get even remotely close to the amount of hits you mentioned previously. I don't take offense to answers that folks give me. What I do take offense to his people who tell me that it can be easily done then don't shed anymore light on the issue and then proceed to tell me I don't listen to any of the suggestions or that I don't do any research on my own. Believe me, I've done more research on this than I care to admit and I can't seem to find any information on what it is I am trying to do. I thought the purpose of this forum was to request help, I don't expect anything. If folks haven't done it or don't have any specifics on the topic I accept that and move on. My hopes was that someone would chime in that had actually installed an aftermarket regulator, not just folks that have never done it and then tells me it can be done. I find plenty of info for Mustangs and other makes of vehicles just not the 6.8. I have no idea what the heck you are talking about when you say that I don't ever seem to answer your direct questions. One of your earlier questions was "what is your concern". I feel I answered that by saying that the engine is knocking slightly under WOT and that I contacted KB and was told by their tech department that they feel the problem is fuel delivery (volume/pressure). How was that not answering your question. Look, I'm not going to get into a pissing contest with you or anyone else here. I appreciate all the replies to my questions but I'm still left with my original question. I assume that no one on here has done what I am trying to do because I have not recieved any responses. I'm sure that someone, somewhere, in this great country of ours has done what I am trying to do. Believe you me, I will get it figured out. The link below is a picture of the OEM regulator. Maybe I was expecting a lot hoping that there was a direct adjustable replacement for this unit but I was wrong. I have found plenty of adjustable regulators on the net but haven't found anything that I can adapt to the fuel rail. I said I consider myself pretty well mechanically inclined, I didn't say I was an expert. Hense my reason in requesting the expertise of the folks on the boards. I was hoping that someone had already done this and could shed some light on the process for me. I don't mean folks that done it to an F150 or some other vehicle, I mean the 6.8l V10. The mounting cup that the OEM regulator fits into is part of the fuel rail. It's not like I can just unbolt the fuel rail, take off the mounting cup for the OEM regulator and replace it with an aftermarket adjustable one. In a perfect world that would be great, but unfortunately that is not the case. In closing, I'm not getting pissed off at folks on here, not sure if that is what you were implying or not. I'm pissed at my problem which seems to me should be an easy fix but I'm finding that that's not the case. Again, I appreciate the effort that folks have been putting forth.


http://www.rockauto.com/ref/Motorcra...tml?CM4907.jpg

 

Googled for "ford v10 adjustable fuel regulator" and found PILES of hits.

http://performance.drivewire.com/getparts/index.aspx?pdef=Fuel%20Pressure%20Regulator|Ford|F-250%20SUPER%20DUTY%20PICKUP|2001||||||Fuel%20Syste m

If that doesn't work, look for Accel part # 74753

Summit has it, around $106.

Looks like the Ford standard bolt pattern. Fits both 5.4L and 6.8L

If Accel makes one, I'm sure there's other brands out there too.


As to why you have such low pressure to begin with, I'd start looking at power to the fuel pump. Bad connection, burned connection, something. Bad ground?

I'd also make sure your fuel pressure gauge is accurate before doing anything else.

Another thing, I also would have changed the stock regulator. Chances are there is some dirt in it, and it's not sealing correctly letting pressure bleed back to the tank.

 

The Accel part number mentioned does not fit the 6.8l V10 and that came directly from Accel. The searches I've done yeilded the same regulator but like I said, according to Accel it does not fit. As far as replacing the stock regulator goes, I'm on my third one. I was hoping that I just got a bad one but that wasn't the case. Pressure remained the same with the new one I just installed. All power and grounds have been checked including voltage directly at the pump, everything checks out ok. I'm almost positive that my pressure readings are correct because I have a rail mounted gauge and an electrical gauge in the cabin and they are within 1 degree of each other.

 

I just checked, and fuel pressure regulator for 5.4 and 6.8 are the SAME part # from '99 through '06.

If that Accel part # fits the 5.4L, it'll fit the V10.

I've dealt with aftermarket stuff quite a few times, and many MANY times found "it won't fit" means they don't KNOW and won't tell you it will.

With the fuel regulator disconnected from vacuum, is the idle pressure still that low?

From my 2001 service manual:

³ Fuel Pressure ³
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³ 5.4L and 6.8L Gasoline Engine ³ 193-310 (28-45) ³
³ Running kPa (psi) ³ ³
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ ÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³ 5.4L and 6.8L Gasoline ³ 240-310 (35-45) ³
³ EngineÄKey On Engine Off kPa ³ ³
³ (psi) ³ ³

 

Art, I've seen that Accel part # listed for the V10 on a few sites but the picture that is shown doesn't look anything remotely close to what the OEM one looks like. That is the reason I called and talked to a tech guy at Accel. I suppose I could give it a try and if it won't work just send it back. The regulator on my setup is hooked up to the boost side of the blower. I'll have to unhook it to see if the pressure changes. Again, to clarify my concern, the only reason I am pursuing the fuel pressure is because the tech folks at Kenne Bell are telling me what pressures I should be seeing at idle and WOT. If I hadn't asked them about it I never would have suspected that they were off. Research and info are appreciated, I'll follow up and report my results once I get the adjustable regulator issue taken care of. Thanks to all!

 

the Ford Manual states it should be 30/45 with a less then 5pund drop within five minutes of just sitting. Just check the system in my f250 v10 today had 39psi with only 2 psi lost after 5 min. So I changed my fuel reg. Fuel filter and Pcv valvel seams to have done the job, plugs, fuel bar, and transistor harness next!