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OK, so bad news for me, good news for all of you. I have confirmed that my active runners are not actuating. As a result, the dyno result I posted is significantly more straightforward showing only the benefit of adding the short tube headers.

I know I've seen other R/T dyno's with the 392 intake which showed a big dip in power when they haven't been tuned to account for the extra airflow after they go short mode. I found it odd that I saw no power dip in the baseline run, so I had to investigate. I double checked the wiring and confirmed that I have 12 V, ground, and the actuator wire throwing ground when engine speed surpasses the ON-RPM, so I am confident that the wiring is OK. I ended up sticking a borescope into my intake manifold and just watched the flaps as I changed the ON-RPM setting over and under my idle RPM to test functionality; they're not moving.

I've removed the actuator and I can move the flaps by twisting the knob that the actuator couples to by hand. The flaps move freely, so they're not stuck or anything.

I then plugged the wiring back into the actuator and left it out to watch its behavior. I had to tape the hole on the backside of the intake manifold to turn the engine on, and upon doing so I note that the actuator performs a single actuation cycle when the car turns on, then nothing. The fact that it can always cycle once on startup tells me that my circuit delivers the required current to make it operate, but for whatever reason it is blind to the "actuate now" signal.

I feel reasonably confident that the problem is the actuator, so I'm going to replace it and see if it behaves. It should be ready for pickup on Monday. In the mean time, I'm gonna sit around being pissed at myself for not figuring this out before I paid for the tuning session.
Uh, boy, that sux. Bad. Based on how you are trouble-shooting, ‘tho, I don’t know of you’ve proven your wiring is working on pin 3. Maybe test that it’s indeed getting shorted to ground before you commit to your new actuator? Doesn’t it’s behavior off the car allude to: “yes, pins 1+ 2 are working, but pin 3 might not be?”

This may be a great case to try the 5v LED trick on pin 4. That should tell you if the wiring to pin 3 is functional.
 

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The Pork Wagon (‘14 Cop Charger)
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I think what you are seeing is mostly the effects of the intake. If you look the air flow at 4800 for the additional displacement of the 6.4 and the more aggressive cam vs air flow potential of potential of the 5.7 with the milder cam my guess is the air flow of the 5.7 at 5400 to 5600 is about the same as the 6.4 at 4800. Every test I have seen . That is why most are not seeing any major lift on the top end of the 5.7 with the intake. The 5.7 is camshaft limited on air flow! All the benefits everyone is seeing are the longer runner length creating more velocity to fill the combustion chamber down low. My belief is Dodge used the longer runners to clean up the bottom end of 6.4 and the runner switch over and cam to make more power up top. No other reason i can see for the added expense and engineering.

The real test will be when someone runs a 5.7 with a healthy cam and compares the intakes! That is where I believe we will see the big difference! I also have the 6.4 on a 5.7. I drop .3 sec 0-60 with no other changes. The bottom end pick up with the 6.4 intake is probably the best buck. I have run it with and without the runner switch and the 0-60 does not change.

Just my thoughts
If the SRV were bad, it would fail that initial actuation at startup, wouldn’t it?

As I understand it, there is some sort of black box (figuratively speaking) installed as part of this mod whose job it is to send the signal to the SRV to actuate once the specified RPM is seen. Can you hook up something to that wire to test for power once the engine RPM exceeds the predefined RPM?

I have a Fluke DMM that has a detachable screen for viewing it output remotely. I would use something like that if I were trying to confirm the voltage on the wire at 4x00 RPM. Do you have anything similar?
 

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Discussion Starter #23
Uh, boy, that sux. Bad. Based on how you are trouble-shooting, ‘tho, I don’t know of you’ve proven your wiring is working on pin 3. Maybe test that it’s indeed getting shorted to ground before you commit to your new actuator? Doesn’t it’s behavior off the car allude to: “yes, pins 1+ 2 are working, but pin 3 might not be?”
Thanks for the reply. I did not elaborate on my troubleshooting, but I did put the multimeter to the plug and confirmed that pin 3 does switch from open to ground at the MDS's on-RPM.

This may be a great case to try the 5v LED trick on pin 4. That should tell you if the wiring to pin 3 is functional.
I also checked pin 4 and it does nothing right now. I think I will go ahead and put the LED on it when I reinstall the new actuator. If I had done that in the first place I wouldn't be where I am now.

Just read this last post........it will be real interesting to see if you get them working if it makes a big difference. I can not see any on my car
I'll keep you all posted!

If the SRV were bad, it would fail that initial actuation at startup, wouldn’t it?

As I understand it, there is some sort of black box (figuratively speaking) installed as part of this mod whose job it is to send the signal to the SRV to actuate once the specified RPM is seen. Can you hook up something to that wire to test for power once the engine RPM exceeds the predefined RPM?

I have a Fluke DMM that has a detachable screen for viewing it output remotely. I would use something like that if I were trying to confirm the voltage on the wire at 4x00 RPM. Do you have anything similar?
Yes, I believe the actuator itself works, but its pin 3 which receives the "actuate now" signal is blind. I'm speculating a bit here, but I could imagine that its programmed to always cycle once on startup. After the initial cycle it awaits a signal on pin 3 to actuate, which it never sees if the circuitry behind pin 3 has had some kind of failure leaving it blind.
 

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Thanks for the reply. I did not elaborate on my troubleshooting, but I did put the multimeter to the plug and confirmed that pin 3 does switch from open to ground at the MDS's on-RPM.



I also checked pin 4 and it does nothing right now. I think I will go ahead and put the LED on it when I reinstall the new actuator. If I had done that in the first place I wouldn't be where I am now.
I hear ya, I pre wired mine for just this event. Just in case you don’t know (and I’m sure you do) the LED should be lit in long-runner mode (IOWs) all the time, and off when pin 3 is signaled by the MSD. If you have no voltage on 4, then it does make sense that perhaps something is wrong with the actuator (as opposed to the wiring on pin 3). Keep us posted!
 

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Discussion Starter #25
All right, here's the latest. I'm very happy with the look of my newly implemented LED. I mounted it up and to the left of the MSD box, both of which are embedded into an ABS cover. They can be seen in Attachment 1.

As for functionality, I am seriously perplexed. I replaced the actuator, and I have the exact same results. I've conducted several experiments, so I'll start here with the simplest test configuration and expand from there.

To eliminate any external variables (my wiring harness, the MSD box, etc.), I've tested the actuator simply sitting on my workbench (not attached to the manifold). Here I can apply 12 V to pin 1 and ground to pin 2 to power the unit. I am certain that I have the pin order correct, as they correspond to the pin designations inscribed on the MOPAR 4-pin connector. Upon powering it up, it quickly cycles the actuator roughly 20 degrees back and forth one time. Pin 3 is open at startup, representing the conditions of the default long runner mode. In this scenario I should see voltage on pin 4 which would drive my LED, but pin 4 only gives a small negative voltage (-0.08 V). Next I can ground out pin 3 by connecting it to pin 2. This should direct the actuator to actuate, but it does nothing.

So in this simplest implementation; 12 V on pin 1, ground on pin 2, and signal by grounding out pin 3, I get a single actuation upon powering the unit and no response to the signal on pin 3. I've replaced the actuator once and got the same result, so I can't really blame the actuator but the electrical inputs seem consistent with every build guide I've seen. Can anyone identify what I might be missing?

Any advice would be much appreciated.

Thanks!
Preston

IMG_20200803_200126254.jpg
 

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All right, here's the latest. I'm very happy with the look of my newly implemented LED. I mounted it up and to the left of the MSD box, both of which are embedded into an ABS cover. They can be seen in Attachment 1.

As for functionality, I am seriously perplexed. I replaced the actuator, and I have the exact same results. I've conducted several experiments, so I'll start here with the simplest test configuration and expand from there.

To eliminate any external variables (my wiring harness, the MSD box, etc.), I've tested the actuator simply sitting on my workbench (not attached to the manifold). Here I can apply 12 V to pin 1 and ground to pin 2 to power the unit. I am certain that I have the pin order correct, as they correspond to the pin designations inscribed on the MOPAR 4-pin connector. Upon powering it up, it quickly cycles the actuator roughly 20 degrees back and forth one time. Pin 3 is open at startup, representing the conditions of the default long runner mode. In this scenario I should see voltage on pin 4 which would drive my LED, but pin 4 only gives a small negative voltage (-0.08 V). Next I can ground out pin 3 by connecting it to pin 2. This should direct the actuator to actuate, but it does nothing.

So in this simplest implementation; 12 V on pin 1, ground on pin 2, and signal by grounding out pin 3, I get a single actuation upon powering the unit and no response to the signal on pin 3. I've replaced the actuator once and got the same result, so I can't really blame the actuator but the electrical inputs seem consistent with every build guide I've seen. Can anyone identify what I might be missing?

Any advice would be much appreciated.

Thanks!
Preston
Didn’t want to give you crickets, P, so I’m responding, but I don’t have any thoughts yet... still digging...
 

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Ok, I’ve got something for you;
digging deep I went back to the writeup from the guy who started it all (I think) and he claims there won’t be any movement (or erratic) if there isn’t a load on the butterfly (meaning pressure within the manifold). I take this to mean that bench testing may not give the simple test you are looking for. Here’s his thread, I’m still rereading:

 

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If you read through at least the initial writeup from the gracious Hemissary, he explains pins 3 and 4 are logic level at 5v. Now I confess this most simple concept goes beyond my understanding (even if this is the most basic stuff to someone like Hemissary) but perhaps it alludes to not being able to simply jam your pin 3 to ground, OR expect pin 4 to function without the correct level within the correct circuit. I’ll keep trying...
 

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The Pork Wagon (‘14 Cop Charger)
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I have an idea of what’s up, but I don’t have the facts to back up my claim yet. I’m currently combing thru the 2000 page service manual PDF I have to find the data I need, so I should have a reply ready by, oh, Thursday probably...oh yeah, and I am limited to viewing that PDF on my phone, so it might actually be Friday before I can find what I’m looking for 😔
 
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I actually read this whole thread long ago, and I’m re-reading for you now... here’s a little excerpt from page 4:


rgot to mention; some folks have tried testing the actuator on the bench with no load on the output shaft. In most cases grounding pin 3 results in no response (a no-load condition can result in zero commanded movement). What you will observe during PWR-up though is the actuator cycle through it's range of motion once and stop. If you want to test it, install it on the SRV manifold.

A simple actuating test is to use a 12V source (lead acid is fine - need adequate peak current flow). Connect pins 1 (B+) and 2 (B-) to power up the unit. Then simply ground pin 3 to B-. Some folks have found the actuator's output shaft and the SRV manifold input shaft do not initially line up. During the actuator install, rotate the actuator until it keys to the input shaft, then gently turn the actuator so the bolt holes line up. In some cases you might need to apply PWR to the actuator so it cycles through it's range of motion while simultaneously lining up the two shafts. Harder to write / explain this than it is to perform...
 

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I’m sorry to be inundating you all, but this is important, too;


Some folks have run into a glitch that I did not point out regarding the rpm switches I tested on the bench. I forgot that in order for a (any) rpm switch to function properly on our rides, it must have a one cylinder mode. The ones I tested using a signal generator and an oscilloscope on the bench all have 4/6/8/10 cylinder options, but not one cylinder.

Because we have coil-on-plug, each injector pulse is a single event just prior to the combustion stroke. I lost sight of this! The negative lead to the injectors that I normally tap into as an rpm signal works just fine for, say the Predator which has an option for single-cylinder mode during data logging. I forgot about it!
 

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The Pork Wagon (‘14 Cop Charger)
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N
I have an idea of what’s up, but I don’t have the facts to back up my claim yet. I’m currently combing thru the 2000 page service manual PDF I have to find the data I need, so I should have a reply ready by, oh, Thursday probably...oh yeah, and I am limited to viewing that PDF on my phone, so it might actually be Friday before I can find what I’m looking for 😔
N/m, I found what I was looking for and it proves me wrong
 

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Ok, here’s my last one for the night, reiterating that you MUST test it installed in the manifold:
A few folks have, or are trying to test actuators on the bench; they here clicking after power-up, but observe no movement of the actuator's driveshaft when pin3 is shorted to ground.

The clicking upon initial power-up is similar to our throttle bodies, the actuator performs one cycle (open / close) then enters standby-mode.

There must be a load on the actuator's driveshaft itself in order for the device to operate properly. This means you must install it on the manifold, then test by observing cylinder #2's SRV valve through the intake plenum with a flashlight (if off the engine) or a boroscope.
 

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Yeah, at this point I think you work as if the SRV is functional and concentrate further diagnosis efforts on the signaling of that module. Is it being commanded properly, etc.

I think that’s a much more likely failure point versus hardware malfunction
 
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Discussion Starter #35
Wow, thanks guys! I actually came across this thread too, probably about the same time you did. As soon as I read,

"NOTE: trying to make the actuator operate without a load (the manifold's actuator rods / valves) will result in erratic operation, or no movement at all. "

I realized my folly and ran back to the garage to plug the actuator back into the manifold to resume troubleshooting. Great news, its working! To thank you for your help, I'll share my final findings with you guys.

Upon plugging the actuator back into the manifold, I was able to watch the runner valves move with my borescope which I piped through the PCV return port into the manifold. I wrapped duct tape around the port so the manifold would remain air-tight with the borescope in place, and made the valves move by changing the ON-RPM below and above my engine idle. On startup, the valves do not cycle open/closed like the actuator did when it was on the workbench. In retrospect, I've realized that the actuator is not cycling open/closed, but is actually cycling closed-open! What is happening is that on startup the actuator rotates in the closed direction until it meets resistance, and it identifies that point as full-closed and stays there until commanded to open. When functioning normally, the valves are already closed so they don't move and the unit declares that the fully closed position. However when the unit is on the workbench, it rotates about 15-20 degrees towards closed, does not find a closed position, and subsequently rotates back close to its original position and sits idle. It does not function thereafter (until cycled off/on again) because it did not identify its closed position.

Prior to all of this, I had observed that my original setup was not working while installed on the manifold via the same borescope method. This seems to confirm that the original actuator was in fact bad. If I had just installed my replacement without trying to bench test it then I wouldn't have gone through all of this headache, but in the end we learned a lot more about how the system works, so that's worth a lot.

Afterwards I took the car out and hammered the gas a few times. I do not feel any power drop when the runners switch to short mode, but perhaps I'm just not very attuned to the feeling.

And the last bit I wanted to share is related to the LED. Unfortunately the LED set up to be powered by actuator pin 4 still does not work. I haven't been able to put a voltmeter to it yet as its a bit harder to access its wiring now that everything's put back together, but I'll try to probe it tomorrow and report back on whether I can get it to indicate the runner status.

Thanks again, talk to you all later!
Preston
 

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On startup, the valves do not cycle open/closed like the actuator did when it was on the workbench. In retrospect, I've realized that the actuator is not cycling open/closed, but is actually cycling closed-open! What is happening is that on startup the actuator rotates in the closed direction until it meets resistance, and it identifies that point as full-closed and stays there until commanded to open. When functioning normally, the valves are already closed so they don't move and the unit declares that the fully closed position. However when the unit is on the workbench, it rotates about 15-20 degrees towards closed, does not find a closed position, and subsequently rotates back close to its original position and sits idle. It does not function thereafter (until cycled off/on again) because it did not identify its closed position.
Brilliant! Now that’s some great new insight I’ve yet to see ANYWHERE! So glad also it’s working! Major props to you and one more shoutout to Hemissary for laying the groundwork!
As far as “the feeling” that it’s working, my wife used to own a Honda with a “VTEC” and I’d describe the sensation pretty similar to that, in that, as you’re climbing into the upper register of rpms, you can feel the engine running out of air (due to the cam on my car at least), so when the short runners do finally open, it feels a little like a clogged drain “whooshes” free. I can’t wait to upgrade my cam to really take advantage.
As far as the LED, you used a 5v, right? I’ll be curious what you discover on this ‘coz it’s something I was hoping to implement as well.
Well done, sir!
Jason
 

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Discussion Starter #37
Brilliant! Now that’s some great new insight I’ve yet to see ANYWHERE! So glad also it’s working! Major props to you and one more shoutout to Hemissary for laying the groundwork!
As far as “the feeling” that it’s working, my wife used to own a Honda with a “VTEC” and I’d describe the sensation pretty similar to that, in that, as you’re climbing into the upper register of rpms, you can feel the engine running out of air (due to the cam on my car at least), so when the short runners do finally open, it feels a little like a clogged drain “whooshes” free. I can’t wait to upgrade my cam to really take advantage.
As far as the LED, you used a 5v, right? I’ll be curious what you discover on this ‘coz it’s something I was hoping to implement as well.
Well done, sir!
Jason
Thanks!

Regarding the LED, at the time I assumed that pin 4 would just switch a 12 V signal so I had used a 12 V LED. Since then we've learned that it operates a logic level, so I need to find a 5 V LED as you suggested with the same housing diameter as the one I've already embedded into the ABS cover. Fortunately Mouser has housing diameter as a search filter option in addition to color and forward voltage, so I've found a pretty good selection to choose from.

Will keep you posted!
Preston
 

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The engine tune should be modified to account for the extra air coming in at WOT above the set RPM
 
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The engine tune should be modified to account for the extra air coming in at WOT above the set RPM
Thanks, Nuke, I reached out to Sean (Hemifever) about that and his response was that my particular tune was already set up for that and will respond well. He’s the expert, not me, so I’m not concerned.
 

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Thanks, Nuke, I reached out to Sean (Hemifever) about that and his response was that my particular tune was already set up for that and will respond well. He’s the expert, not me, so I’m not concerned.
Good deal
 
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