Who else is using the RCD Dual Fuelers?

[B585Ford]

I think I asked this before but what are you running for a lift pump system? Have you tested pressure for the system while driving, as in making sure its maintaining under load and that the pump isnt weak? Also how it it plumbed into both the k16 and cp3. I have no idea how rcd recommends to plumb it, but Id think the two different pumps would require different operating pressures?

Could it be that if you replaced both injection pumps with new ones that you could have gotten a dud? Maybe try replacing each one at a time with one from a friend that is know to work, or have them tested?


On edit... I see your sig says you have an airdog with elite upgrade. As far as i know an airdog can run like 15psi maxxed out, if its in good shape. I dont know what cp3s are supposed to run but Ive heard of people supplying some with 50psi or so. Id be skeptical on an airdog being able to supply one.

A CP3 from that factory for a Dmax doesn't even have a lift pump. If the LP is dying then it could ne the problem, otherwise the LPFP is not likely the problem.

I believe the OP said he knows he is getting fuel to the distribution block. If that is so, I would think pulling the line running to the CP3 and checking it with the engine running would be helpful. If that is putting out fuel, remove the line from the CP3 to where it connects would be the next step. If all of those are putting out fuel, it would almost have to be on the supply side of the LPFP that cant keep up under WOT conditions..

 

[mike@haller's]

There either has to be a low pressure fuel problem. Or it has a leak or a misreporting sensor (unlikely but possible). My truck with a cp3 ran fine with no wiring to it. The rail jumped around some but it held rail and didn't over pressurize at all. I would verify for sure you have good low pressure fuel with a gauge to both pumps. Then I would look into monitoring vcv and pcv on the ford pump to see if it reacts to unplugging the pump. There are quite a few of these systems out and running with great results. Which makes me think it's something in the setup wrong.

 

[91turbogsx]

Cory...

Both bumps are being fully supplied with low pressure fuel correct? Yes. I've also played with different pressures.

Fuel rail pressure sensor is reading properly? Yes. Installed new FRP sensor. Same reading before and after.

HPFP Pump Cover Kit harness is not damaged in any way, shape, or form? No. The old one was fine and just installed a new one as well according to Fords specs with zip ties on the connectors, etc.

The HPFP is not experiencing any issues with the VCV/PCV? Brand new K16 is reacting the same as the old one.

The nozzles are not larger than 60%? They should all be 60% but I guess I don't know for certain. They were brand new.

The truck is not leaking fuel into the crankcase from a fuel rail, or the high pressure fuel pump? Truck has about 5k miles since it's last oil change and has not raised the oil level at all or look diluted.

There is not a fuel pressure leak at the fuel rail pressure sensor? New sensor was torqued to spec.

Have you tried putting stock nozzles in to see if the problem persists? No I have not.

The ECM is not defective and causing a downstream issue? It runs fine other than just not holding RP under WOT and surging.

That's my checklist; I'm sure I missed plenty, I'm not as smart as some of these guys but this is all that could come to my mind as a potential gremlin.

Jared

See above..

This weekend I'm gonna try to do some more testing and monitor low pressure fuel wherever I can in different areas under WOT. But I'm fairly certain it is good. In regards to the surging if I accelerate (40-50% throttle) once it starts surging it'll go away and rail pressure will rise proportionally until I let off and try to maintain a constant speed, then rail pressure starts surging. So if I had a low pressure fuel issue I feel like I would notice it while accelerating as in little hiccups in RP or something to that effect. RP will read normally as long as it's not full PW. It'll hold 17k psi solid under WOT.

 

[mike@haller's]

Do you have a dash daq? If so can you get some data logs to see what exactly its doing?

 

[91turbogsx]

Do you have a dash daq? If so can you get some data logs to see what exactly its doing?

Yes I should be able to do that.

 

[mike@haller's]

Get a datalog of

Desired Rail
Actual Rail
Fuel pulse width
Mass fuel desired
Fuel temp
Rpm
VSS
Mgp

Get a good log going from a low throttle position to full throttle so we can see what the rail is doing. Also try to get a cruise log showing the surging. Post them up here and if you can send them to me in an email as well. Easier for me to read them if I put them in excel.

 

[91turbogsx]

Sounds good. I appreciate it Mike!