No dual cp3 controller
- Thread starter DMAX497
- Start date
well you'll have to still run a custom built harness to piggy back the one single into the second pump... What's that gonna run if someone sold them? Probably charge 125 bucks just for that harness! I think fingers controller is about 300 bucks. If you rescaled the regulators to cut power in half, I guess in theory you'd wouldn't need the controller for that.... But then what's the ecm gonna think when when it makes twice as much fuel pressure then what it wants? I just don't see that happening. You'd have to foul the Ecm somehow to keep it from freaking itself out, I don't see you being able to do that with just efilive. That being said (and I could be off base) I'm still interested in hearing about this is.
The ECM is going to do the samething it did when I threw 85% over pump on it, make the truck run like chit. It took me about 10 tries to get the rescale right through EFI. If guys can make 200% over pumps run I don't see why two pumps would not work.
Brayden and I can do it no problem. We have been doing it for the LML, but is now offered for LBZ/LMM. It as though it came from the factory this way. 2 cp3s from 1 output.
I sell the controllers for $180 shipped to the public. The driver is rated at 4 amps and I fuse it for 3 to protect regulator and circuit.
The issue is the driving circuit in the ECM. Driving two FPRs requires twice the amperage. Each FPR takes ~4 amps dead short and about 1.5 amps if you keep the duty cycle less than 90%.
LB7 and LLY ECMs would trip on over-amperage. I can't speak for LBZ and later, but would be surprised if the driver can handle the load for long without over heating which would, BTW, trash the ECM.
The issue is the driving circuit in the ECM. Driving two FPRs requires twice the amperage. Each FPR takes ~4 amps dead short and about 1.5 amps if you keep the duty cycle less than 90%.
LB7 and LLY ECMs would trip on over-amperage. I can't speak for LBZ and later, but would be surprised if the driver can handle the load for long without over heating which would, BTW, trash the ECM.
GMC_2002_Dmax
The Still Master
I don't see any advantage, you still control it with an ecm, you still need a piggyback to split the single signal.
So at the end of the day I would rather run a controller then run a few wires.
Kind of like a relay for a electrical accessory, it takes the volts or amps you need to run something safely without worrying about overheating or overtaxing a circuit.
:thumb:
So at the end of the day I would rather run a controller then run a few wires.
Kind of like a relay for a electrical accessory, it takes the volts or amps you need to run something safely without worrying about overheating or overtaxing a circuit.
:thumb:
The CP3's are full blast when there is no current, it takes current to reduce pressure.
Sure, you can just run the CP3's with no controller. But it won't idle. It will only run OK at full blast. This is not actually useful.
To experiment, unplug your CP3 and try to drive your truck.
Sure, you can just run the CP3's with no controller. But it won't idle. It will only run OK at full blast. This is not actually useful.
To experiment, unplug your CP3 and try to drive your truck.
Cp3
After fighting a problem for two years lets just say to keep it simple. Every add on piece is just another thing to cause a problem or go bad. Keep It Simple Stupid!
After fighting a problem for two years lets just say to keep it simple. Every add on piece is just another thing to cause a problem or go bad. Keep It Simple Stupid!
Pat, Kory & Fleece are using the factory ecm to control both cp3's...
I'm with Stingpuller less is better.
It has worked flawlessly on LML for hundreds of trucks. All h&s dual pump kits sold have this tuning on them. I like the idea of having a customer simply plug strait into the plug coming off the harness split
Into both pumps.... Takes around 2 mins to do and never worry about controller failure. My understanding as well is that a lb7/LLY could not handle the current, but LBZ-LML should have no issues. A few more trucks doing it and I will feel confident... We see folks with many random controller failures, and this is simply another option.
Pat, with our ECM tune it will idle and regulate as though it is stock with a single pump.... Follows factory curve from top to bottom.
Into both pumps.... Takes around 2 mins to do and never worry about controller failure. My understanding as well is that a lb7/LLY could not handle the current, but LBZ-LML should have no issues. A few more trucks doing it and I will feel confident... We see folks with many random controller failures, and this is simply another option.
Pat, with our ECM tune it will idle and regulate as though it is stock with a single pump.... Follows factory curve from top to bottom.
Mine has been for 20k miles, HS truck has been for over a year.... And we have countless doing it on LML with no issues.
On LBZ there are only a few doing it now. So we will see how they hold up. I will also try and find out what exact load the driver can physically take. Obviously, this hasn't been anything we have marketed for anything other than LML. So only time will tell.... The idea of taking 2 mins to plug up your dual cp3 without ever having to worry about controller failure is a good idea, IMO. We will see how it works out!
Cp3
Not to talk for Brayden or Kory but here's what I know. The ECM is rated at 4 amps. Now we all know gm puts in a safety factor above that. Each reg will pull .7 of a amp. Less than one amp each. Now for the tuning side of it that you will have to get Brayden or Kory because it's not just cut it in half on the regs. It won't work that way. It took a bunch of trial and error to get it were it would idle smooth. Starting was also a issue at first so it's not a plug and play without there help. Anything to make these things simpler is all good in my book.
Not to talk for Brayden or Kory but here's what I know. The ECM is rated at 4 amps. Now we all know gm puts in a safety factor above that. Each reg will pull .7 of a amp. Less than one amp each. Now for the tuning side of it that you will have to get Brayden or Kory because it's not just cut it in half on the regs. It won't work that way. It took a bunch of trial and error to get it were it would idle smooth. Starting was also a issue at first so it's not a plug and play without there help. Anything to make these things simpler is all good in my book.
GMC_2002_Dmax
The Still Master
It shouldn't be too hard to figure out, regulator scaling amp tables are available and the closed loop corrections are also available.
Anyone with some time to spare could play around with it, and any professional tuners used to correcting for mismatched pumps, modded pumps and or regulators should be able to "figure" out whatever is needed to make it work.
I would like to see if someone can actually measure load draw on the factory circuit.
As anyone who tunes these knows and anyone who has been around knows that it require no amperage to make fuel pressure at WOT, but requires a lot to clamp down the regulator to maintain idle and then correct fuel pressure quickly after chopping the throttle.
Maybe a dual pump kit is in my future for R&D.
:thumb:
Yeah, it isn't too difficult. Efi doesn't have all the tables in their software for doing it.... But easily done.
Cp3
You would be one to say its stupid and why would you and then go and try to duplicate! Enough said.
You would be one to say its stupid and why would you and then go and try to duplicate! Enough said.
DOH!!! OK, I understand now.
Never gave it much thought since the kits come with a regulator. Hence you can use the kits with any type of tuning, handheld or custom.
Never gave it much thought since the kits come with a regulator. Hence you can use the kits with any type of tuning, handheld or custom.
Those are not correct values. As I posted before; straight DC, the regulators draw about 4 Amps. At 90% duty cycle, the impedance keeps it just under 1.7 Amps.
At idle, the regulators are at about 40% duty cycle. (single pump) 60%-80% dual pumps. OEM regulators are fully closed somewhere around 90% and fully open somewhere around 10%.
The strain on the power circuit is when the system tries to dump pressure and command max duty cycle. Unstable rail pressures work the hell out of the regulators too.