Electric fuel lift pump for Cummins C8.3 engine

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Electric fuel lift pump for Cummins C8.3 engine

June 30, 2014, 11:09:00 am

We are looking to add an electric fuel pump, probably mounted on the frame rail over the start batteries when we now have a Raycor fuel filter. The idea is be sure that at high fuel flows that the injector pump has adequate supply. There could also be redundancy with electric & mechanical fuel lift pumps. And it would be nice to use electric fuel pump to aid in starting after fuel filter changes.

Would like new pump to flow fuel through existing mechanical fuel pump and existing Cummins engine mounted fuel filter to minimize changes. We also have fuel lines going to "wait to start" intake manifold cold start, so the fewer modifications to the original fuel flow the better.

Looking at two competitive systems:

FASSride - Titanium Series

PureFlow AirDog® ? Supplier and Manufacturer of Fuel Air Separator Systems and

I would like to add an electronic digital fuel pressure dash gauge, so I need to find a way to mount a new fuel pressure electric sender on the injector pump input banjo bolt.

I have read about new injector pump fuel return valves, but our return line banjo bolt has little clearance between the injector pump and engine, so I don't know what our options are.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #1 – June 30, 2014, 12:28:27 pm

Here is what Tom Hall did to his MCI. He had a different engine but same idea. Does away with hand primers, etc.

Tom Hall

Pierce

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #2 – June 30, 2014, 01:08:11 pm

Pierce,
A little funny, those check valves are great, DDC Charged about $38.00 each about 10-15 yrs ago, but I bought them from MCI for $2,39 each, work great on fuel.

Did my priming slightly different, used ball valves with the electric pump, did not trust those check valves to pass as much fuel as It could need.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #3 – June 30, 2014, 01:22:35 pm

Dave,

The valves list at about $60 today but the local timber company got one for me for $32 about 4 years ago for our U300. Ball valves are very convenient for a lot of stuff. With our Detroit, the check valve has a spring on the back side that keeps the return line from draining back to the tank so keeps pressure in the system after turning off the engine. My old one had a crack and let air into the system. An electric primer keeps the hands clean and primes the filters in seconds.

Pierce

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #4 – June 30, 2014, 01:35:10 pm

I don't really see the point of an electric pump for priming on the 8.3 unless you have had problems.

I know many people replace the mechanical lift pump completely with an electric pump. I considered this, it's probably just as easy to carry a spare lift pump and change proactively every 5-10 years.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #5 – June 30, 2014, 03:09:45 pm

Barry,
I just ordered this snubber valve for the P7100 injection pump on our mechanical Cummins. Should be here in a few days. It has a 1/8" NPT port for the pressure sender for the GlowShift gauge.

TORK TEK CUMMINS 14MM X 1.5 PRESSURE GAUGE SNUBBER CBS010 - Tork Teknology

I also ordered the upgraded overflow valve which I plan on installing after I get a set of baseline measurements from the existing overflow valve. As you pointed out, looks like I will be removing the AC compressor mounting bracket (again) to get the old one out and the new one in.

I'll post up the numbers when I get everything installed.

I have no plans at the moment to upgrade to an electric pump setup. I didn't know you were able to leave the mechanical lift pump in place. I thought everyone was removing it altogether.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #6 – June 30, 2014, 03:27:22 pm

Robert,

Looks like you and I are on parallel paths to fuel system upgrades. I have a fuel pressure gauge + the same snubber ready to install, plus one of the Tork Tek OFV020 Adjustable Overflow Valves. Just haven't had time to try the installation yet. I agree - it looks like it is going to be VERY tight getting at the old original valve to remove it and install the new one. On my coach, like yours, the AC compressor is mounted on a heavy plate which is right on top of the injection pump. I'll probably have to remove the compressor and mount just to get enough room to work on the overflow valve.

On the 5.9L engines, they often have to grind a recess on the intake manifold material to provide sufficient clearance to remove the overflow valve (banjo bolt). I hope this will not be necessary on my engine. We'll see...

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #7 – June 30, 2014, 03:50:37 pm

Here is one thing that might help when we try removing the original overflow valve (once the AC compressor is out of the way). The photo below shows the short metal tube which is attached to the injection pump by the banjo bolt/overflow valve. Note that the mounting bracket is slotted. The little bolt that holds the fuel tube mounting bracket is partially hidden behind the engine front cover assembly, but I can get a small ignition wrench on it. I'm hoping that I can remove the rubber return fuel line from the tube, then carefully loosen the small bolt just enough that the bracket can slide up. Then when the banjo bolt is unscrewed, there will hopefully be sufficient room to slide the whole fuel tube+banjo bolt+washer assembly up and out from between the injection pump and the intake. We'll see...

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #8 – June 30, 2014, 05:42:18 pm

A few thoughts:

What is the reason for tapping the banjo bolt for a fuel gauge? Seems like it can be anywhere in the system on the output side of the mechanical pump, possibly drill and tap the top of the secondary fuel filter housing.

I see the reasoning behind adding the electrical pump but suspect that for both mechanical and electrical pump to be effective for both greater flow and redundancy it will be necessary to parallel them rather than series install. Might need a check valve in supply line before the pumps to work properly. Check valves add restriction.

I had planned on installing a mechanical pump and valves for hand priming after pressing endlessly, and futilely on the primer on the mechanical pump. Since I changed it out recently though I find that a few strokes on it with the key switched on (!) pushes the air through the injector pump, this is with prefilled filters. You can hear it faintly squeak as it opens the check valve on injector pump. Crank it and it starts.

Here's the low tech solution from a respected authority. Don't laugh.... Squeeze Bulb Priming on Diesel Powered Boats

I expect your fuel filter changes will be far and few between with additional pump capacity.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #9 – June 30, 2014, 07:50:26 pm

I took another look at our injector pump and see the difficulties relating to removing overflow banjo bolt and metal line bracket bolt.

Questions:

Fuel input banjo bolt has a single hex head.
I see overflow banjo bolt has 2 hex heads. Is the smaller 2nd hex for the spring fuel return valve?

Will the overflow banjo bolt & valve come out without removing AC compressor bracket? I don't know how deep/long the bolt/valve is, so I cannot visualize.

It seems that if the overflow bolt is too long it will back out against the engine, not the AC bracket?

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #10 – June 30, 2014, 08:30:58 pm

Quote from: Barry & Cindy – June 30, 2014, 07:50:26 pm

I see overflow banjo bolt has 2 hex heads. Is the smaller 2nd hex for the spring fuel return valve?

Smaller hex is retainer for spring inside the valve. Yours is a "older style" valve. The newer ones do not have that 2nd smaller hex - they have a recess with a captive steel ball that retains the spring and valve assembly. See photo below. The one on my engine is like this - should give me a little more clearance for removal. Don't ask me why your newer coach has a "older style" overflow valve, and my older coach has a "newer style" overflow valve - I don't have a clue. My complete injection pump is obviously all original, all painted in the same beige color, and has never been "wrenched on" that I can tell.

Will the overflow banjo bolt & valve come out without removing AC compressor bracket? I don't know how deep/long the bolt/valve is, so I cannot visualize.

I won't know the answer to this one until I actually try it. I think I will remove the compressor and mounting plate to make it easier to R&R the overflow valve.

It seems that if the overflow bolt is too long it will back out against the engine, not the AC bracket?

That is correct - it will hit the intake manifold. I found a good discussion of this problem here:

Overflow Valve Removal - Dodge Cummins Diesel Forum

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #11 – June 30, 2014, 09:05:27 pm

Quote from: Chuck Pearson – June 30, 2014, 05:42:18 pm

What is the reason for tapping the banjo bolt for a fuel gauge? Seems like it can be anywhere in the system on the output side of the mechanical pump, possibly drill and tap the top of the secondary fuel filter housing.

My thought is that the fuel inlet connection (banjo bolt) on the injection pump is simply the easiest point to access, at least on our engines. In the pickup trucks with the 5.9L, they often do take the pressure signal off the engine mounted fuel filter housing, again because of easier access.

Wherever you tap in, it is supposedly critical to use the "snubber", which has a precisely sized orifice. Otherwise, the pressure pulses from the transfer pump will render the pressure gauge unreadable (and eventually kill it). Here is a good discussion of the procedure for installing a remote electronic fuel pressure gauge:

Instructions for the CBS010 Cummins Banjo Snubber

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #12 – June 30, 2014, 11:32:55 pm

Quote from: cajk – June 30, 2014, 03:27:22 pm

Looks like you and I are on parallel paths to fuel system upgrades.

Thats because I'm unashamedly stealing your ideas.

I've stolen plenty of Barry's ideas too but the electric lift pumps are a little too rich for me at the moment.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #13 – June 30, 2014, 11:41:08 pm

Yes, too expensive, plus I have read about a lot of problems with both systems, including a high failure rate. I think the stock system will do fine after we refresh the 15 to 20-year old critical components.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #14 – August 03, 2014, 07:56:18 pm

Barry,
Did you ever get one of the electric fuel pump options or is this put on the back burner?

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #15 – August 03, 2014, 10:32:07 pm

Robert, thank for asking...

Back burner. I want to get a fuel pressure gauge installed before. Also I am temporarily stonewalled by electric fuel pump instructions that tell me to join overflow return fuel lines from injectors to injector return line before installing electric pump. I need to understand more the ramifications of relocating injector overflow return line. We now know where injector return is installed at mechanical lift pump thanks to y'all.

I am also stymied by the small clearance between injector pump and engine head making it difficult to remove & replace fuel return valve. Know about grinding the head, etc to make more room, but don't care much for them at this point.

So I feel stalled, but am still interested and poking with all parts, including a temporary easy move to replace original mechanical lift pump with a new mechanical lift pump.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #16 – August 03, 2014, 10:51:59 pm

Quote from: Barry & Cindy – August 03, 2014, 10:32:07 pm

Robert, thank for asking...

Back burner. I want to get a fuel pressure gauge installed before. Also I am temporarily stonewalled by electric fuel pump instructions that tell me to join overflow return fuel lines from injectors to injector return line before installing electric pump. I need to understand more the ramifications of relocating injector overflow return line. We now know where injector return is installed at mechanical lift pump thanks to y'all.

I am also stymied by the small clearance between injector pump and engine head making it difficult to remove & replace fuel return valve. Know about grinding the head, etc to make more room, but don't care much for them at this point.

I don't know how cajk got his overflow valve installed without removing the ac compressor. I was able to remove the old valve without removing the bracket with some difficulty but ultimately successful. Trying to replace it was a different story. I dropped the new valve about 5 times back behind the injection pump and it would get caught but eventually fall down on top of the air compressor, that is until the 5th time. I simply couldn't find it anywhere after looking/feeling/searching for 4 hours and ended up just buying another one.

After that ordeal, I just removed the AC compressor and bracket and the job was perfectly easy, which is what I should have done the first time. Not that hard to remove the AC compressor bracket and can be done in about 15-20 minutes.

My understanding of the installation of the FASS just means that you have to T into the existing fuel return line near the new electric pump installation since the electric pump sends the air and some excess fuel back to your tank through the return fuel line. Should be easy enough considering the return lines run right in through the area where your existing fuel filter is and probable new pump location.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #17 – August 04, 2014, 12:43:53 am

Thanks for the honest humor on dropping the valve so many times and then losing it.

Robert, after you removed the AC compressor & mounting, were you able to get the original overflow valve out without grinding out the head? And the same for the new valve going back in? What overflow valve did you use and is it adjustable? Any special wrenches needed. I assume an open end or box could do the job. Did a lot of diesel flow out? Did you find a fuel pressure gauge for the dash? What psi range does lift pump put out?

Thanks

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #18 – August 04, 2014, 08:15:22 am

Quote from: rsihnhold – August 03, 2014, 10:51:59 pm

I don't know how cajk got his overflow valve installed without removing the ac compressor.

It helps if you have little girlie hands like me!

But seriously, I really have very manly hands, it's just that I also have the finger dexterity of a world-class brain surgeon!

But really seriously, Barry, TAKE THE AC BRACKET OFF! If I was doing it again, that's what I would do. As Robert says, after that it is easy. Except for the little bolt that holds the return fuel tube mounting bracket. I'd like to hear how he got that one loose. For me, it was very difficult.

Once the return fuel tube bracket is free, just use a box end wrench to loosen the valve, unscrew it, slide the valve (still inside the banjo fitting on the tube) and the tube out from between the injection pump and the cylinder head. Plenty of room. Installation of new valve is just reverse process. Use new washers. Put a little oil on washers before installing - never install dry!

Just a little fuel dribbled out when I removed the old valve. Stuff a paper towel in gap between injection pump and head to catch drips (and anything else you might drop).

I used the Tork Tek OFV020 adjustable valve.

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #19 – August 04, 2014, 09:45:01 am

Since this OP is referenced to the old lift pump assembly and centers on the 5.9L (I've got the 01' ISB),
I left the old lift assembly in place and simply bypassed it. What can I say, I'm lazy and don't live under the hood.

For the gauge.. any upper port on the injection pump will give you lift pump pressure.
I used the bleeder port as the location for the new lift pressure gauge.

I was going to route the gauge inside to the door post but decided to leave it mounted on the injection pump.
Much better than the trouble of another hole in a firewall.

Keeping an eye on the gauge will tell the condition of the filter (when to change.)
The first canister is a water separator and the second is the fuel filter.

I believe that both of the pumps mentioned earlier are now owned by the same operation.
I'd suggest getting a few spare pump gaskets (o-ring's) since that is the ONLY issue
I've had since going to the FASS system.. they are pretty much bullet proof setup. pc

Re: Electric fuel lift pump for Cummins C8.3 engine

Reply #20 – August 04, 2014, 10:01:13 am

Quote from: Barry & Cindy – August 04, 2014, 12:43:53 am

Robert, after you removed the AC compressor & mounting, were you able to get the original overflow valve out without grinding out the head? And the same for the new valve going back in? What overflow valve did you use and is it adjustable? Any special wrenches needed. I assume an open end or box could do the job. Did a lot of diesel flow out? Did you find a fuel pressure gauge for the dash? What psi range does lift pump put out?

No grinding of anything involved. With the AC bracket removed, it is as simple and easy as taking out one bolt and putting in another.

Once your mechanical fuel pump shuts off, the overflow valve has no pressure to deal with and only a few drops or a small trickle of diesel comes out. This lack of pressure can be verified by the fuel pressure gauge. I have the 3in1 Glowshift gauge that has boost psi, EGT, and another psi reading that you can use for whatever you want (fuel, in my case but it could be changed to air, etc.). Amazon.com: 3in1 Black Face Pyrometer, Digital Boost, and Pressure Gauge:

I'll be playing around with the fuel pressure gauge adjustments today but my initial readings with a new factory mechanical pump indicate that the mechanical pump can't keep up with the engine's need for fuel. I'll keep everything updated in this thread- Fuel System Science Project

Quote from: cajk – August 04, 2014, 08:15:22 am

As Robert says, after that it is easy. Except for the little bolt that holds the return fuel tube mounting bracket. I'd like to hear how he got that one loose. For me, it was very difficult.

I used the Tork Tek OFV020 adjustable valve.

I never removed that little bolt that holds the fuel return line nipple. It did seem extremely hard to access and it was probably necessary to remove if you don't remove the AC bracket. Once the AC bracket is out of the way, there is enough play in the return line nipple to have everything line up nicely.

I used the same valve as Chuck.

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