1994.5 - 1997 7.3L Power Stroke Diesel  

E-Fuel Woes.

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  #16  
Old 03-16-2015, 08:33 PM
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Just throwing this out in case the OP doesn't have this licked yet. When I did my DIY setup I replaced the fuel hoses lines going from the frame to the engine. In putting the new ones on, I crossed them up. I could get zero flow from the fuel pump but could hear it churning away.

After some head scratching I realized what I had done and that a fuel pressure regulator is basically a closed valve if you pressure it backwards. I think I finally figured it out when I cracked the fittings going to the regulator. I got no pressure where I should have it and a geyser where it should have been low pressure. Doh!!

In short: OP, make sure you don't have any lines crossed or you'll never get fuel through the system past the regulator.
 
  #17  
Old 03-16-2015, 09:10 PM
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Thanks guys. Actual turned out to be a weak pump.

It was strong enough to pull fuel out of a jug but not strong enough to pull fuel through the filter.

New pump and it primed instantly.

Thanks for all the help and ideas.
 
  #18  
Old 03-17-2015, 12:48 AM
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What pump are you using?
 
  #19  
Old 03-17-2015, 10:33 AM
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I was using an old Carter that I had laying around for ever. It was used, pulled it out of my buddies wrecked SD.

New pump is just a Precision Pump from O'Reillys. Came with a 3yr warranty.
 
  #20  
Old 03-17-2015, 01:14 PM
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Originally Posted by stainlessstroker95
Which line did you hook up for supply on your selector valve. I find it hard that the electric fuel pump won't prime its self. When I did my e fuel I had it hooked up wrong but as soon as I switch them it took right off.

Agreed. double check this.



Install instructions I built mine by to double check my DIY system... http://www.strictlydiesel.com/Produc...SystemTips.pdf

I know this may sound like a dumb question but you have your inlet and outlets connected properly on your filter bases correct?If you can feel suction from the pump it almost sounds like there is an obstruction in the feed from the tank/filter bases, or you have an obstruction downstream of the pump... pictures sure would help us out.
 
  #21  
Old 03-17-2015, 08:08 PM
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Could low fuel pressure cause a miss in only one cylinder?


Now that everything works and the truck runs, I have a miss and a knock in either cylinder 1 or 3. UVCH is fine, although I've yet to actually pull the valve cover.


Odd thing is, the truck ran very smooth for the first 5 minutes but didn't have a lot of power.
I also had to repair the IPR harness.

I don't have anything to properly measure fuel pressure at the moment.
 
  #22  
Old 03-17-2015, 11:09 PM
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Originally Posted by williameub
Could low fuel pressure cause a miss in only one cylinder?


Now that everything works and the truck runs, I have a miss and a knock in either cylinder 1 or 3. UVCH is fine, although I've yet to actually pull the valve cover.


Odd thing is, the truck ran very smooth for the first 5 minutes but didn't have a lot of power.
I also had to repair the IPR harness.

I don't have anything to properly measure fuel pressure at the moment.
If you can't check fuel pressure then how do you know if is set correctly. Low fuel pressure makes for some noisy funky running truck.
 
  #23  
Old 03-18-2015, 07:19 AM
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Originally Posted by fordman67
If you can't check fuel pressure then how do you know if is set correctly. Low fuel pressure makes for some noisy funky running truck.
Agreed. You need to check the pressures to make sure you have sufficient fuel pressure for those injectors. They aren't happy without the proper pressures. They will make some really funky noises...
 
  #24  
Old 03-18-2015, 08:59 AM
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I'd highly recommend you add a pressure indicator on your regulator... I was just asked the other day why I was installing a gauge under the hood that isn't usable in the cab....and this is exactly why. You need to set the regulated pressure. A liquid filled pressure gauge and a couple 1/8 npt fittings from Lowes and you are good to go, heck I bet you can get a liquid filled gauge at Lowes too.... or any auto parts store.
 
  #25  
Old 03-27-2015, 08:14 PM
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Ok, so the saga continues.

Recently made a fuel pressure gauge and hooked it up.

I have good base pressure with the key in run. 68-70psi.

Whenever the truck starts, pressure slowly drops to 0. Truck is still running though. The pump also turns off whenever the truck starts, so it's an electrical issue.

My wiring for the pump is extremely simple.

PIN 86 is powered by the old Fuel Bowl Heater Circuit.

According to the information I've gathered, this should be PIN 4 or the Red/LT Green wire in that connector.

Is there something I'm overlooking?

Thanks.
 
  #26  
Old 03-27-2015, 09:15 PM
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What is this "extremely simple" wiring you speak of? Is there an oil pressure switch in the circuit that could be wired backwards? To wire an efuel system with the oil pressure switch is not "extremely simple". If the pump shuts off when the engine starts, I'd say we start with a discussion on the wiring.
 
  #27  
Old 03-27-2015, 09:47 PM
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Originally Posted by DIYMechanic
What is this "extremely simple" wiring you speak of? Is there an oil pressure switch in the circuit that could be wired backwards? To wire an efuel system with the oil pressure switch is not "extremely simple". If the pump shuts off when the engine starts, I'd say we start with a discussion on the wiring.
Extremely simple as in no oil pressure switch.

12V from the battery through a 25amp fuse to Pin 30 on the relay.

85 to ground.

87 to pump to ground.

Fuel heater wire to 86.


Nothing else. Kept it this way until I can throw the dough at the strictly diesel wiring kit.
 
  #28  
Old 03-28-2015, 05:18 AM
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If the pump is quitting when the truck starts, you need to do some diagnosis to find out why. Using a test light or meter, check for voltage at 87. Once the truck dies. if you lose power at 87 then check your grounds, and the power coming from the heater to 86. Something isn't right (or you got a bad relay).

If you still get power at 87, then move back to the pump and check for power there. If there is still power there, then check the ground for the pump.

What regulator are you using?

What is your fuel level in the tank you're drawing from? If you lost the "shower head" in the tank, it may just be sucking air if you're below a quarter tank. I just had to replace BOTH of my shower heads because they were broken to pieces and I'd lose fuel pressure if the front tank dropped below about a third of a tank. 5 Gallons of fuel added to the tank would be cheap insurance if you're at all suspect that this may be an issue.
 
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