Ok, here is some quick back ground, 95 F250 intake and exhaust. I had a leak coming from the quick couplers that run from the frame to the metal lines on the block. So to fix the leak most of the metal lines were rusted as well I just took all of them out, bought some high pressure fuel injection hose (3/8) for supply and (5/16) for return to replace these lines. Did so and no leaks and truck ran and idoled fine. But, under load the fuel filter light would flicker and then stay lit, once coming off load after a few seconds the light would go off. (did feel a slight loss in power and the EGT's were lower than normal as well) The fuel filter is fairly new so I didn't think it was that b.c I didn't have this problem before I changed the lines. Thinking it might be a fuel pressure issue I checked it at the valve on the FPR and it was at 43lbs at idol. I added in the BB trick and checked it last night with a different pressure gauge and it was at 93lbs. The first gauge I used only went up to 60lbs and is a standard dial tire guage. The gauge I used the 2nd time is a stick style and is good up to 120lbs.

First off if the pressure is that high will that wreck anything or can I just leave it alone? I didn't drive the truck at all, could air be caught in the line giving a faulty reading? It just seams weird that it would go from 43lbs all the way up to 93lbs. Could the BB not be in all the way? Has any one else delt with too high of fuel pressure? I wouldn't think it would be a problem but wanted to check here first. Any ideas I can check when I get home tonight. Let me know what you think and any advise will be great!!! I am going to be towing this weekend and wanted to clear this issue up.

 

93 PSI is too high. You need to open up the FPR again and see if there is a chance that something got misaligned and isn't going together right. Sometimes that can happen and the fuel pressure will be really high like that. You're going to kill the pump if you leave it that high.

As far as your issue goes, here are my two theories. One is that you may have freed up enough dirt replacing your fuel lines that it clogged the fuel filter. Replacing the filter would be a quick and easy way to rule this out and it will only cost you about $20.

What I am afraid is the case (and this is not what you probably want to hear) is that the rubber fuel lines are your problem. The fuel pump on these trucks is on the engine. That means that the fuel is SUCKED out of the tank and up to the front of the engine. On a typical gas truck, the pump is in the tank and your rubber fuel lines would have worked fine, but since this engine has a mechanical fuel pump that pulls the fuel through the lines, I think when you get the engine under load and start really using some fuel, the pump is producing enough draw to collapse the fuel lines and close them off. This would produce essentially the same symptoms as having a clogged fuel filter and it would trigger the switch to turn on the fuel filter light.

Again, I would replace the filter first and if you're lucky that may fix the issue, but if it doesn't.... that only really leaves one other alternative as the root of the problem.

 

ok, so a follow up, replaced the fuel filter and no change. I also tried to adjust the BB and spring in the FPR. When I took the spring out for some reason it was slightly bent at the top. Put everything back together with out the BB and now I have no fuel pressure. Won't even register on the pressure stick. I did place the slightly bent portion of the spring into the little triangular holder that it sets in so the part of the spring that sticks out is still strait. I did notice as well the the fuel line I ran for the supply was sucked flat and it seems as if DIYMechanic is correct that it is sucking the fuel lines partially closed.

Since this is the case, other than buying new steel lines to replace the old existing ones that I bent out of the way it there a different hose that I can run for the supply line. I was thinking a flexible metal (bendable line) that can be molded into place and clamped to the other fuel lines with the blue style hose that is used on the fuel bowel and such. If this is the case can a 5/16th line be used b.c it looks like the metal lines off of the frame are about that diameter. I could really use some help, and I didn't want to have to pull the power steering pump and brackets to get to those steel lines. Feed back and info. will be much appreciated and DIYmechanic was right on. Thanks for the good info.

Sam

 

The steel line on the front of my reg cab cracked years ago and I just ran a rubber line from the pump, down behind the front accesories and clamped onto the steel line on the frame, by-passing the flex lines and the steel line on the engine. after 3 or 4 years I have never had a problem with fuel issues or the line collapsing. although I gutted the fuel heater, filter sensor and water in fuel sensors long before that, so for all I know it might make the light come on if it had one, but I have never lost power so I never worried about it.....


On edit I dont know the size but I got the fuel line from NAPA, rated for diesel and gas, 60 PSI I thought, so its not just a rubber hose, its got some support braided in.

Diesel Rod

 

Most people will tell you that, yes. However... my truck runs 75-100psi consistently, never an issue one. It was the same scenario when this pump and fuel bowl were on Whitey. Why it's so high, I have no idea. FPR has been rebuilt with no change, never had any issues with the way the truck runs, never any blown fuel lines or cracked fuel filter lids, never any change in PSI after a fuel filter change, etc.

 

I'm not sure what's happening in your FPR but if you can't get the spring straighten you may want to get a new one.

Checking the fuel pressure on these trucks can be tricky. Since it is just a ball and spring regulator the pressure will flucuate with fuel temperature/viscosity. When the truck and fuel temp are cold the pressure will be 10-20lbs. higher than the reading when it's warmed up. Another factor is the fuel consumption by the enginge. Checking pressure while not under load will be very different from checking pressure under hard acceleration. It can drop 20-40lbs. at WOT. I have a fluid filled 100psi hydralic gauge plumbed into the port where the schrader valve was and ran into the cab so I cn monitor fuel pressure while driving. It reads as follows.(I do have a bb in my FPR)
Cold at idle 60-70lbs
Warm at idle 50-60lbs.
Warm at WOT 40-50lbs.
Warm at WOT running 160*F veggie oil 30-40lbs.

I would be suspect of a clogged pickup screen in the tank. These trucks shouldn't suck a 3/8" rubber hose flat unless there is some restriction somewhere. Also check to make sure the rubber hose you ran isn't kinked anywhere. If there are no restrictions in the tank or kinks in the line you could step up to a 1/2" fuel line which would have less restriction and less chance of getting sucked flat.

Hope this helps.

 

Chase,
Is the 75-100psi at idle cold?
What type of gauge are you checking it with?
How many miles on one fuel pump at that pressure?

Trying to narrow down some variables.

 

I don't know that I would recommend that arrangement. If your hose spings a leak you're going to have fuel spraying into the cab. To each his own, but that just doesn't sound like a good idea to me.

I would look at a restriction in the tanks as well, since you're correct it shouldn't be sucking the lines flat.

Just out of curiosity, what grade line did you use? What pressure is it rated for?

 

For safety I totally agree with that, you should change the mechanical to an electrical gauge.

 

I appreciate your concern guys but I am using hydraulic hose and fittings rated for over 3000psi. The line is well insulated anywhere it comes in contact with sharp items. It has already been there for a couple of years with no problems. Even if by some chance I where to spring a leak I don't think 50psi of diesel spraying under the dash is going to be the end of the world.

Before going this route I had problems with several other gauges. Mechanical and electric, with and without isolators and needle valves. The high pressure side of these pumps can pulse hard enough to damage many gauges and sensors.

The fuel line I use coming from the tank is the cheap stuff from the auto parts store 3/8" Gates XL. Rated for around 60psi I think. It's not the fuel injection hose.

 

I wonder is switching to SAE30R9 fuel hose would help. It is definitely stiffer stuff than the SAE30R7 that you used.

 

75-100 psi cold, warm, lukewarm, doesn't seem to matter
Isspro EV2 electric gauge
Mileage unknown... this pump was on whitey when I bought her

 

I read through all the posts, I did use the SAE30R9 hose 3/8 like I said and it has been sucked oval. I started the truck today, it hardly ran, idoling rough and had to bring it over to my buddy's garage to work on it over the weekend. If WestcostSlider could let me know what hydraulic hose did you use??? Did you put ends on it and if so how did you get them to fit on the OEM fittings and such or did you just use a hose clamp? Anyone have any other ideas, I just need to get the truck running right. To get a new spring for the FPR where can I get one of those from? Thanks.

 

I am wondering if you could just buy some 3/8" and 5/16" steel line and bend your own lines. What configuration is the truck (Regular Cab, EC, CC, etc and what bed length)? Just wondering if there would be someone that might have the stock steel lines they could let go. I might have a set for a RCLB, but other than that I am no help.

Just out of curiosity have you tried it on both fuel tanks? I am going back to the theory that the fuel pickup may be plugged. I doubt it would act the same way on both tanks if that were the case.

 

I will get to work on the truck on Friday, I will try the other tank. The lines from the tank to the frame right by the motor are good. Just from that quick connect up to the fuel pump. The truck is a long bed extended cab.

Does anyone know where approx. 6ft. of the blue hose can be purchased from, that seems to have the rigidity compared to the other tubing I used. Any insight for sourcing this stuff would be great.