for those with e-fuel. I currently have the ever loved oil pressure switch as the power for the fuel pump. I suffered a long crank issue twice today that leads me to believe that is quickly on its way out. It there a better replacement for the pressure switch? Or should I just by-pass it for now and find an inertia switch?

Thanks for the input

 

If I understand how the efuel works correctly, the oil pressure switch is to keep the power relay for the pump closed while operating, therefore it would be the culprit if your motor dies 30 seconds after starting.

The way my system is set up, a key on signal closes a second relay also giving power to the pump but is on a timer so it opens after the key has been on for so long.

How new are your glow plugs? You seeing white smoke coming out of the tailpipe when you have a rough start? Do you have fuel pressure during hard start?

 

that's the odd thing, it isn't really a 'hard' start. It cranks then struggles to start, as if it is barely getting fuel. I don't feel like it is a glow plug issue, as it did it with the truck pretty warm and the next time I started it, which was just a few minutes later, it fired just fine. I didn't get the chance to monitor fuel pressure while cranking so I am not sure, but it was about 55 psi while running, which is where I keep it. I am thinking about changing the fuel filter just for good measure while I am at it.

I am going to try and by-pass it temporarily until I get another relay wired and installed. I am just hoping that it will still start without power to the pump while it is cranking. It will have power while the key is in the run position, so hopefully it will have enough time to pressurize the system and have enough fuel to start while it is cranking.

 

so it works just fine without the pump running while the truck is cranking. I just let it prime while the glow plugs cycle and all is well. I will probably rewire it so it doesn't run every time the ignition is on but for now atleast I am back running. Hopefully without the fear of it not starting, we will see tomorrow.

One thing I did discover is that I am only getting about 10.5 volts to the fuel pump. I am going to have to go over my grounds and connections to see where the issue is

 

You should really think about getting a fuel pressure gauge.. It would help out a lot in trouble shooting

 

Good point, up to this point I would just check the gauge under the hood if I needed to. But it would be nice to monitor in the cab.

 

After reading the reports on oil pressure switch problems I never wired one in. I have my efuel pump relay wired in series with a manual toggle switch on the dash, the ignition switch and an inertia switch (just in case). Since the dashboard mounted toggle switch is in series with the ignition switch, I leave the toggle switch on all the time. It's main purpose is in case I want to run some key on diagnostic tests without running the fuel pump.

Here's a link to the inertia switch. Lots of other cool stuff on that website:

First Technology Inertia Switch, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits

The low voltage to your fuel pump could be caused by failing contacts in the oil pressure switch. My thoughts are that the oil pressure switches are mainly designed to activate an idiot light and the normally open contacts aren't designed for continuous duty. I'm not sure this is true though. Edit: Re-reading your posts I see that the low voltage was there after you jumpered the oil pressure switch.

So far my system has worked perfectly but I don't have a lot of miles on it yet. I also added a dashboard Auberins fuel pressure gauge.

 

Just wanted to put a cap on this one since I believe I resolved it. In the end I don't think the oil pressure switch was the problem. When I changed my filters my first stage with water separator had a lot of trash in it. I don't know where it came from but I am glad the filters caught it. I changed the wiring and will be adding an Inertia switch next week but it is starting great now.
I am trying to decide how I want to install a fuel pressure switch

Thanks to all that replied!

 

My bowl delete/fuel regulator has a threaded port that accepts a fuel pressure sensor. You might have a plug you can remove and replace with the sensor.

 

That not a bad idea. I have a pressure gauge on it now at the regulator. I am thinking of using a T so I can keep the gauge under the hood and have a port for a sensor