Trying to understand CP3 opperation (Elect.)

RPM Motorsports

smokinum
May 13, 2008
3,271
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Central Valley Ca.
Why is it not possible to run a 2nd CP3 off the stock CP3 wiring with splitters? Im not understanding the "Control Box" need. Does it regulate the 2nd CP3's flow compared to the 1st?
 

Mike

hmmm....
Feb 17, 2007
2,184
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San Angelo, TX
The contoller, in effect, splits the load between the two cp3's. Reality is, the controller just duplicates the signal from the ecm. The ecm has no idea more than one is present. So, the ecm actualy does the control. The ecm, in effect, sees the one cp3 able to do the work but at half the duty cycle ( depending on how you view it, on or off ). Hope this makes since.

Of course this is my take watching it with a scope.
 
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Idaho CTD

Junkie
May 28, 2008
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Idaho
The controller mimics the signal from the ECM for the 2nd cp3. The ECM controls the pump(s) based on desired vs. actual rail pressure. The ECM doesn't have the amperage output needed for 2 cp3's and that is why you need a controller. It's controlled by PWM like the solenoids in the tranny. Most meters see it as about 4-4.5v (at idle) but it's actually 12v's fluttering on and off.
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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slc tuah
english for non-engineers? i am curious as to what this looks like compared to other electrical signals....you can pm if you dont want to clutter the thread

Are you talking Syliscope ? if you tested with a volt meter i doubt you would see the pulse , it would simply look like DC voltage maybe varying a bit , on a Syliscope is were you could see the "pulse" or shape of the "pulse "
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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slc tuah
i might have gotten in over my head , i am not a electrical wiz, i just want to understand pwm better compared to regular current


the pluse needs to be Veiwed on a syliscope it is not 100 % duty cycle ( unless it decides it wants to be ) it is a pulse duty cycle that vary's by demand and would be considered the width , think of injector pulse width :D , it can not be duplicated with anything but a circut board to my knoledge .
 
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McRat

Diesel Hotrodder
Aug 2, 2006
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This is the way I understand PWM and our CP3's:

Let's say you need to adjust a spring-loaded solenoid from open to closed, and you want to vary it with a computer. By turning the power on and off rapidly, you can adjust the power level going to the solenoid's coil.

Power on all the time = solenoid all the way open.
Power on 1/2 the time = solenoid half way open.
Power on 1/4 of the time = solenoid quarter open.
Power off = solenoid closed.

This kind of variable control is very easy to do with computer, since all it uses is ON/OFF anyhow.

Our CP3's when no power goes to them are full blast, the solenoid is stuck open. When we apply full power to the them, they are closed, and produce little if any fuel.

So if you want "half" fueling, let's say you leave the power on 50% of the time, and off 50% of the time. This will work for one pump. If you have two pumps hooked to the same feed, you'll actually be supplying 75% fueling, since each pump will see only 25% of the power.
 

SIKDMAX

Highway Burnouts!
Sep 14, 2007
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So if I have no power coming off the leads for both CP3s from my dual fueler harness than that is the issue with my truck.

AKA can check for 12v at CP3 connection. If no voltage present, there is a problem. Correct?
 

Idaho CTD

Junkie
May 28, 2008
179
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Idaho
Power comes from the ecm not the cp3. If you have elevated rail psi then the signal is bad (most likely from the controller). You can meter the signal to the cp3's and with a standard meter it is usually in the 4-4.5v range.
 

Mike

hmmm....
Feb 17, 2007
2,184
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San Angelo, TX
So if I have no power coming off the leads for both CP3s from my dual fueler harness than that is the issue with my truck.


AKA can check for 12v at CP3 connection. If no voltage present, there is a problem. Correct?

Just don't try this at home :D

Adding too much current will pop it, right bad. ;) You know, release the factory smoke from the fpr.



The way I remember, number 1 is a pass through and number two is the clone. But, may be the controller manufacturer who says so. No voltage could be a max fueling command. If you by pass the cp3 controller and plug the original wire back into the cp3, with the key on the cp3 fpr should hum.
 
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SIKDMAX

Highway Burnouts!
Sep 14, 2007
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Was on the phone with Dan earlier and he said check for voltage coming out of the PPE controller going to the 2nd cp3 and then call back. Just trying to understand what Im looking for.

Carry on, interesting info.
 

Mike

hmmm....
Feb 17, 2007
2,184
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San Angelo, TX
The second controller supplies the voltage/current to the second cp3 so if there is none and the fuse is good with voltage present and you have a good ground then...... Best to get the correct info from the manufacture.;)
 

MadMaxx61

Devilmaxx
Oct 13, 2008
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english for non-engineers? i am curious as to what this looks like compared to other electrical signals....you can pm if you dont want to clutter the thread

It would like much like this if you were to read it out. It would change the frequency it as more or less fuel is needed.


109871_8mg.jpg


Square / Rectangular Waves

The square wave is another common wave shape. Basically, a square wave is a voltage that turns on and off (ie goes high and low) at regular intervals. An injector waveform is fundamentally a square wave - the injector is either on or off. A rectangular wave is like the square wave, except that the high and low time intervals are not of equal length. That is, the 'on' and 'off' times are not equal. Again, this is often the case with an injector, where at low loads the 'off' time will be much longer than the 'on' time. The waveform shown here is from a Hall Effect road speed sensor.

Hope this helps a bit I have not played with a oscilloscope in years.

also this is not my info I had to look it up and got the pic off of "Using Oscilloscopes on Cars, Part 1"
http://autospeed.com/cms/title_Using-Oscilloscopes-on-Cars-Part-1/A_109871/article.html
 
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Fingers

Village Idiot
Vendor/Sponsor
Apr 1, 2008
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White Oak, PA
The CP3 control is actually on the ground wire...

So, there will always be voltage on the one wire. The other will use a PWM method for controlling the connection to ground.

The controller failure can be:

No power supply.
No connection to ground
or
Constant connection to ground.

But, what do I know....
 
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TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Mid Michigan
In simple terms, is the control box simply an amplifer for the ECM signal to the second CP3?
 
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