WMO system almost there, keep getting air driving

[subway]

well i finally got my power steering/fuel pump in my truck and working, mostly.

guess i should explain the system, i took a gm power steering pump that does not require a tank and welded up some brackets to splice it into my serpentine belt system. then since a power steering pump can put out somewhere in the range of 1000-1500 psi i gave it a bypass regular to bleed off the pressure. basically it sends all the extra flow and pressure back the the fuel tank. the fuel is spliced into the system with high temp fuel relays on the intake and exhaust end of the fuel system. this keeps my stock system completely operation and goes back at the flip of a switch on the dash.

it holds a nice 5-10 psi range with the pressure regulator i designed but i cant get the air out of the system. it is constant and a decent amount, trouble is i also don't see any leaks or where is is pulling the air from. i am so close and want to have it going for a long trip.

actually now thinking this out do you think it is a problem having the return line and fuel bleed off "T"ed together. could i be back feeding air into the system?

thanks, i know this is a little out there for most but i am getting at the end of my rope in patience and ideas now.

 

[Ironman03R]

I wonder if the pump is causing the fuel to foam and thats your source of air. What is it doing when it gets air in the system? Could it be theres a restriction somwhere?

 

[subway]

i thought about the pump airating sp? but i am not sure how, if it is i am screwed. the air is constant, it keeps bubbling out the shrader valve in spurts when i purge. i cant run the truck off the system for more than a couple of minuts and it air locks and has to be bled out. thats directly after i get all the air out i can before i switch over. once it stalls i find there is a big air bubble in the sytem.

there should not be any restrictions, at least that i can see. i have a prefilter off the tank and it is clear.

i am still thinking now that maybe the pressure relief that is plumbed in the the return line might be backfeeding oil and air up my return lines.........i will have to try my theary tonight. any more ideas are great, thanks

 

[04_6.0]

jred what did you find out about the air getting into your system im intrested in doing this.

 

[subway]

well i found it was simply a fitting on the vacuum side of the pump. its hard to track but i got it after i found it seeping later.

i put about 700 miles on the system with the rally and besides clogging my prefilter from tank rust it performed flawlessly.

i will have to get the part numbers and info together when i get the chance for anyone else who might consider doing this. it is not for the faint of heart, not overly complicated but it is involved. hope fully i can pass on enough to help others avoid expensive mistakes.

 

[04_6.0]

awesome that great! i finally got an idi so now i have something to tinker with.

 

[subway]

ok I guess I should explain my system, I have since put several hundred mile more on the system and like i mentioned besides rust clogging my pre-filter (which I can tell with a gage) it works flawlessly. that is not to say it will work as well long term or when the weather turns cold, it might but I have not tested it that far.

right now I have a bed tank that goes through a pre-filter then to the pump. the pump is a Chevy power steering pump that I picked off the shelf at my local azone for about $75. it then sends the fuel up to a plate heat exchanger that it run off my heater hoses and through a extra 7.3 fuel filter head. the output of the fuel filter head has a T in it, this seems to be the trick to get the system to work at a decent pressure.

one leg of the T goes to a bypass fuel pressure regulator. this lets all the excess pressure return back to the tank, a power steering pump can produce a couple thousand psi if you let it. right now with my regulator it bounces between 5-10 psi. it is a homemade one I designed a called a favor with a machinist to finish. thanks Bob! otherwise you should be able to find one from jegs or summit easily. IT HAS TO HAVE A RETURN LINE TO BLEAD OFF PRESSURE, a deadheaded pressure regulator will not work and it will just build until something lets go.

the other side of the T feeds to the high temp greasecar fuel relay then into the injection pump. there is another fuel relay on the return side as well so it flows back to the tank I am using. my stock system is then left to work as is and is only interrupted when I hit the toggle on the dash and cut the aux system in. the fuel relays also default to the stock system just in case of failure. with only the line from the filters to the injection pump being changed I get purge times in just 30 sec to a minute.

so ups and downs
downs
1. you always have to have fuel in the system or the pump will burn out. although it should not be a habit of running your fuel dry, the pump is running when the engine is running and needs lubrication.
2. this is a fairly involved system to implement, I enjoyed it because I am a tinkerer but I needed a welder and to do some metal work to mount up the pump in my serpentine belt system.
3. I am adding another possible point of failure for a long trip, although if needed I can swap the old belt on and just make my aux system inert.

pluses
1. I can drive completely on free fuel once my truck warms up and I switch over.
2. it seems to be a robust system, I have not had a electric pump be able to move straight WMO with success. the pump is driven by the engine so it has far more available pumping power than a little electric motor.
3. it works and is easy to use, once the temp hits close to 180 I flip a toggle and just flip back about a minute before I shut down.

I know this is just a overview and not a detailed install, I modeled my system somewhat after waste veggie oil systems since they are doing very similar things to run veggie.

I will get part numbers and pics when I get home.

disclaimer: this is just what I did and works for me so I thought I would share, if your truck catches fire going down the road and crashes into a crowd don't look at me. this is all at your own risk and even I admit is not really tested out yet.

 

[04_6.0]

Sounds like a pretty cool setup uve got there. I will keep looking in on how it is holding up to day to day use. I think until ive got a long trip on my hands my 20 mile round trip to work might not be worth it. Ill stick to my 50/50 mix i guess.

 

[Oilguy]

Do you think this will work on a Cummins Common Rail system?

 

[Oilguy]

I've been thinking about your system and the problems that you have had to overcome and I have come up with an idea I wanted to throw out there...

First let me say that I have a system like what I am about to describe so I know it works but I was thinking of adapting it for fueling a truck...

What about a pressurized tank? I have a mobile oil change business and I have battled for years with all kinds of pumps trying to move oil... I have a new system that I built that uses Propane Cylinders that I pressure up to the desired PSI and it just pushes the oil out... I have run several thousands of gallons so far over the last 8 months and have had 0 problems. I was thinking that if you needed 5 or 10 PSI then you could regulate the pressure in the tank to 5-10 PSI and not have to worry with a return line... Then you could run the oil though a filter and heated line with a switch and solenoid and the complicated issues with adding aux belt run pumps and pressure relief valves and extra pressure regulators would be eliminated....

Like I said I run a system like this now everyday without a single problem and I think that it could easily be adapted to fit this application... What do you think??? ???

OG

 

[91f2504x4]

I've been thinking about your system and the problems that you have had to overcome and I have come up with an idea I wanted to throw out there...

First let me say that I have a system like what I am about to describe so I know it works but I was thinking of adapting it for fueling a truck...

What about a pressurized tank? I have a mobile oil change business and I have battled for years with all kinds of pumps trying to move oil... I have a new system that I built that uses Propane Cylinders that I pressure up to the desired PSI and it just pushes the oil out... I have run several thousands of gallons so far over the last 8 months and have had 0 problems. I was thinking that if you needed 5 or 10 PSI then you could regulate the pressure in the tank to 5-10 PSI and not have to worry with a return line... Then you could run the oil though a filter and heated line with a switch and solenoid and the complicated issues with adding aux belt run pumps and pressure relief valves and extra pressure regulators would be eliminated....

Like I said I run a system like this now everyday without a single problem and I think that it could easily be adapted to fit this application... What do you think??? ???

OG

I am not sure how a diesel engine would like trying to return unused fuel to a pressurized tank. Most if not all diesel engines require a return to the tank, in our application (idi engines) this would not work, you would have numerous return line issues.

 

[Oilguy]

With a system that you could "tune" the pressure to the exact PSI needed to run the motor... Why would you need a return line? Does the pressure need to adjust for the engine RPM?

I am saying that when the truck is running on #2 it runs on the stock system and then when you hit the switch to run it on WMO is switches to a completely different system....
I am trying to think of a way to simplify it down to the basics... You need Fuel going to the IP... Right? Is the Return line after that?
I have a Cummins CR so I am not as familiar with your IDI setup...

I just know that the Mobile oil change system that I have works flawlessly and delivers plenty of volume at whatever pressure you desire.

 

[91f2504x4]

You need Fuel going to the IP... Right? Is the Return line after that?
I have a Cummins CR so I am not as familiar with your IDI setup...

Yes, there is a return line from the injection pump and from every injector, if you try and block this off the truck will not run or run very poorly. It is not a correct pressure issue that requires the return, many people regulate the psi of the supply pump with a regulator at let's say 7 psi, but they still have to have a return from the injection pump and injectors to the fuel tank, it is just how the system works. All mechanically injected diesels are this way, all the way back to the old old diesel trucks and tractors.

 

[ameristar1]

The best thing to do is to try it out and see how it runs. I've never seen it done with the existing fuel injection system style that we have, but that's probably because no one ever tried. Give it a go and tell us what happens.

 

[kerrynzl]

I am presently building a similar system for a Mitsubishi Pajero [called Montero in the USA ], I recommend TWO return lines when using a power steering pump.
One return line is the normal diesel return to the tank, The other return line is from the pump to a pressure regulator which then dumps back to the tank.
Tee off the return line BEFORE the pressure regulator [ to the heat exchanger, filter & IP etc ]
All the line pressures will then be equalized by the pressure regulator .
Remember , Pressure is Pressure and Volume is Volume. [ many people confuse the two ]. A good positive displacement "Vane type" power steering pump can shift a lot of volume when geared correctly.
My experience with "Dry sump" systems on competition engines is the further away the pump is from the tank, the larger the ID of the oil line [ on the suction side ]
I would recommend a -10 [ 5/8" ID ] on the suction side, and a -8 [ 1/2" ID ] on the return line and to Tee off to the IP system.

Has anybody here had any experience with an exhaust gas Heat Exchanger ?
I am thinking about using TWO heat exchangers "in series". The first heat exchanger is heated by exhaust gases, the second heat exchanger is heated by engine coolant.
The exhaust gas heat exchanger should be able to heat the oil in approx 60-90 seconds after start-up.
On the Mitsubishi Diesel there is a neat little wastegate device that re-circulates exhaust gases into the intake for fast warm-up.
This wastegate is vacuum control via a vacuum / electric solenoid [ and is usually disconnected ]
This wastegate can be used to control an exhaust gases to the Heat Exchanger
I intend to wire the solenoid to a couple of Temp sensors [ Fuel temp & Water temp ] to close the wastegate when the Fuel and Coolant are up to operating Temperature [ then the coolant heat exchanger does the heating ]
My Goal is 100% WMO