raw fuel coming from manifold

[oldbluef250]

Alright I'll tell you all the mods I did when I had the motor out.

When I did the swap, I put in a forged rod motor, rpm-incs old motor that was in his van. Exhaust ported heads, comp 910 springs, smith bros push rods, H-11 head studs, 350/200 hybrid injectors that were gone through by casserly before they were sent to me, srp1, ih bellowed up pipes, 38r and s475. I am just running the 38r for now, the other turbo will get mounted in the next couple of weeks.

For the fuel system I have a tsd sump. From there it has 5/8" line to the filters and fuel lab pump, form there it has 1/2" line to the block, from there it has #10 braided line up to the valley. Once it gets to the valley, it T's off to size 6 braided line to the back of each head. When it comes out of the heads up front, there is 3/8" line going into the regulator on each side. I used the stock 5/16 return line going back to the tank.

The return line may be my issue. I know I have read that you should use 3/8" line going back to the tank, but I didnt think that 1/16" difference in the line would make that big of a difference.

Also for the fuel pressure, it doesnt necessarily go up. I think it just went up before because I turned the regulator up once I saw that the fuel pressure went down.

It seems that once I take if for a drive after it has sat for a while and it gets back at 65 psi , fuel pressure will slowly drop until the truck just runs like crap. I dont think that fuel is coming out of the back of the heads. Like I said, I THOUGHT that it was fuel. After the truck sat over night, I realized that my heater lines were leaking where they go into the firewall. Idk how I could mix up fuel and coolant, but its possible coolant could have dripped onto the manifold

I should also mention that the pump is in "reduced" mode.

 

[TARM]

Ok that helps a lot. I am sorry I was not following your build and did not realize you did a full motor swap. Lots can certainly happen when doping that.

Lets work the fuel pressure issue first and see if that fixes the other issues. Now if you start the truck and while running set the fuel pressure to say 65 psi. You then go for a drive and when you check it again it was reading 80 psi. Is that correct for one of the times? I think you also mention seeing it drop on you as well correct?

I do not see that return line causing the issue. Unless it has something weird going on the old sending unit in the tank. If you can set the pressure at idle that return line is seeing the maximum flow return as the injectors are using the least amount. The pump is a constant flow or should be if functioning correctly. To rule on the return line for sure test to see how low you can drop pressure when at an idle. If you back out the set screw can you drop pressure below 60 50 40 30 how low can you take it. If you can drop it down well below your set point then its not your issue. If you can't then its could be the issue. But still I think you said you are seeing pressure drops as well so not sure its that.

My first guess if the return line checks out would be a faulty regulator.

 

[oldbluef250]

Oh I never wrote anything on a build or really told anyone about it so you wouldnt have known.

Fuel pressure will be fine, so long as I dont drive anything more than stock. If I drive it harder than that, pressure will drop. I know I have plenty of fuel getting to the injectors with the fuelab pump

I also am beginning to think its a regulator issue. I think i'll order another one and see if that cures it. I dont really want to wait to get another one through warranty crap.

 

[TARM]

Order one if its the issue send the other one in and then sell it at least you can recoup some of your money that way.

Do not just take it for granted that becasue you have a fuelab you are getting plenty of fuel. Its controlled by a circuit board and if its not working right maybe its possible you are getting far less fuel than you think.

Another thing I just thought of that may explain this. What voltage are you seeing at the pump? If you are low @ idle that will greatly effect pump output. If instead of 13-13.5v you are seeing say 10v or even under you could have low flow and be hurting your pump as well.

Did you run 10 wire thru a 30 amp relay and use the factory 16g harness lines as control wires?

 

[oldbluef250]

I will have to measure voltage tomorrow. Yes, I am running the pump with a relay exactly the way you described it. 10 g. wire going to the pump.

 

[TARM]

unless your battery or alt is on its way out or a bad cheap relay it should be 13 volts + with good quailty 10 wire and a good ground.

 

[oldbluef250]

Voltage was 13.5 when it was cold, after a short drive once it was warmed up, it was 13.3v, so its good there. I guess I'll order another regulator next.

I've noticed now that fuel pressure will drop the more you drive it. Even if I drive conservatively, it will still drop, just not as fast as when I drive harder. So it seems that once it has been shut off for a while, like a few hours, pressure will be normal once I start it up again.

 

[TARM]

Since its under warranty I guess there is no reason to take the regulator apart. If that would be what I would do to see whats going on in there. IT sure seems like the regulator would have to be it. The only other thing would be the pump but the reg is more likely.

Now I am assuming your gauge is good. Are you sure it is? I had one recently that I felt was reading low as I had to really crank the reg closed to much for the flow of the pump I was using. I started putting some pressure on the gauge and tapping it. The pressure bounced all over the place. Ended up I was about 20 psi higher than it showed. Just rule it out. Maybe you can borrow a gauge. A 100 psi oil pressure gauge will work as well as a fuel one if someone you know has one. you can pick them up cheap too for a china brand.

 

[Tree Trimmer]

just thinking out loud, but it seems that the longer he drives it, the lower pressure he gets. if the regulator was bad, would the pressure be stupid all the time, instead of just after a drive?

if the pump was on the way out, even with good voltage, that would cause the issues he is having. sounds like the longer the pump is working, regardless how hard, the longer the pump is on, the lower the fuel pressure gets. to me that says fuel pump.

an electric motor getting hot will do just that. i have a auger on a grain bin does just that. the longer i run it, the slower it augers. shut it off for a bit, picks speed back up. my money's on fuel pump.

im not familiar with fuelab pumps, do they have a "reset button" like a regular electric motor, where if it gets so hot or draws to much voltage for some reason it shuts itself off, till it either automatically resets or you manually reset it? or is there no fail safe, and it either works, or kills itself?

 

[TARM]

That was also why I put it could be the pump. That does make sense the way you put it TT. The FL at least the one I had has no reset button. Now maybe its like the Bosch pumps and has a thermal overload sensor switch that cuts flow WAY back. On my Bosch 044 I am running it flows 80gph@75psi but if that thermal overload switch trips its down to 8gph until it gets back down to a temp that will allow it to reset. Even with very light driving that would certainly cause fuel pressure to go WAY down. The FL may only cut it back 50% or some thing though or on a scale based on temp. That would certianly explain his symptoms. Then one time if he resets the reg pressure while its cut back and then lets it cool and takes it out and checks it now back at full power its going to be spiking high pressure for sure. Then the other way around it will be way low.


Glad my pump is stilling it a container of cool diesel fuel at all times now.

 

[oldbluef250]

But if my pump is bad, why can I turn the regulator up, once the fuel pressure has dropped to lets say 50 psi and its ran for a while, and maintain 65psi again? Then once I drive it after I've turned it up, it will spike to around 80 psi.

 

[Tree Trimmer]

i can only go by what i read, and its kinda bounced back and forth, i have had minor issues following what your saying.

that ^^ to me says regulator.

 

[TARM]

Like I said start with the reg and go to the pump next. Again we are sure the gauge is good CORRECT?????

If its not to much a PITA temp hook up the stock fuel pump and set the pressure drive around and see if the pressure is changed when you get back.
I

 

[oldbluef250]

Im pretty sure the gauge is accurate. Its just a little fuel pressure gauge that goes 0-100psi that I got from summit.

If the new regulator doesnt solve my problems then I'll try to rig up my stock pump. I will kinda be a pita though since the ports on it are so small compared to what I have now.

 

[TARM]

Just an FYI but I got a similar gauge if its the kind that just screws into the reg from Jegs. Sound the same as yours. It had my pressures showing all over the place. Not saying that this is the case with you just to check it. When I put some pressure on it or torque to turn it the pressure would change. Before that I was having trouble setting pressure.

 

[cfdeng7]

Pull the gauge off and rig it up to run to an air compressor so u can see if its functioning properly

 

[Vader's Fury]

Im pretty sure the gauge is accurate. Its just a little fuel pressure gauge that goes 0-100psi that I got from summit.

I have 2 of the same gauge on my truck right now. The one on the reg reads 68# every time I pop the hood and check it. Now the one that I have on a remote line on the cowl of the truck will float from 60-75# at different times. And it is not bouncing around, just shows different pressures at different times.

I would try a different gauge or check the gauge with a air pressure regulator before going though all the work of switching back to a stock fuel pump.