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It took me a while to find the time to look for the CPS valve on my 2019 6.4L. Today was super nice outside so I took some photos and a video that I'll post on youtube, then I'll come back and update this with a link. The canister purge valve is part of the evaporative control system. It's a small 14V solenoid valve that allows the electronic throttle valve (ETC) to suck fuel vapor from the purge canister. Fuel vapor is collected by the purge canister while parked. The canister is a charcoal filled can that collects fuel vapor from the fuel tank.

In older cars, the purge valve was typically a linear solenoid meaning that it could be opened gradually. They didn't audibly click because the drive signal was typically 200Hz and the valve was controlled by varying the dutycycle of the signal. The valve moved softly so you would never hear it. If you could put your ear directly onto it, you would hear the 200Hz hum.

In newer cars, the linear solenoid has been replaced by the so-called digital CPS valve which is cheaper to manufacture and is a simple on/off valve. The linear valve had about 4 to 6 mm of travel and a tapered armature and seat. The further it opened, the more flow. The digital valve is only fully open or closed, no definable in-between. The average flow volume is determined by the overall dutycycle or on-time (open) with respect to off-time (closed). The typical operating frequency is around 16 Hz but the valve can work from 10Hz to about 40Hz. The digital CPS valve has a small hard rubber tip on its armature and it tends to harden in cold weather so when the car starts up cold, the CPS is louder than normal and that's when people are most likely to hear it.

Purge typically happens only for a few minutes after startup and then reduces greatly or stops. In other words, don't let the noise get to you. It doesn't go on forever.

If anyone is considering tampering with the CPS, I highly advise against that. Purge is critical to the EVAP system. Disconnecting the CPS valve electrical connector would leave the vehicle without any purge at all. Certainly, this will trip the check-engine light. By passing the valve would certainly flood the engine with purge flow and cause severe stalling and lugging that would never end. The reason the CPS valve operates at a reduced dutycycle and at a high frequency of movement is to provide a controlled average amount of flow. The ECU stops purging during acceleration and resumes when the engine is near idle or at a constant speed. Several sensors are monitoring this behavior... so do not mess with it or you'll be sorry.

I will provide a link to some photos and a video soon.

Just a note, for anyone who wonders, I have been an electronics engineer for the past 26 years working on evap product development for Siemens -> Siemens-VDO -> Continental -> Vitesco Technologies. This has been constant employment. Just the company name has changed several times over the years. My function has included creating many prototype level electronic drivers for linear and digital solenoids (including CPS, PPS linear or proportional purge solenoid, EGR exhaust gas recirculator, ETC electronic throttle valve, GPA general purpose actuator, and more). Speaking of GPA, there's one on the rear of the intake manifold on your 6.4L engine. It moves the runner valves inside the manifold. I helped design the GPA and the electronics within it. I also programmed it, both prototype and production level code. And no, I'm not allowed to share the source code. That's company IP. But I have to admit that I'm a little proud of the fact that there's a little of myself in every Challenger and Charger (and other Dodge vehicles, and GM, and others).

Bill B.
So bill do you have any idea where this noisy bastard is on my 6.1 ? And is there any way to silence this thing without using a hammer. The noise drives me nuts and actually is embarrassing if you start it up in front of anyone.
 

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Honestly, I don't know where the CPS valve is on a supercharged engine. I've never seen one in person. However, if the noise that you are hearing is so loud as to be embarrassing and annoying, I suggest that it is not the CPS valve. Sounds more likely to be valve lifters, but that's only a guess.

Bill B.
 

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Honestly, I don't know where the CPS valve is on a supercharged engine. I've never seen one in person. However, if the noise that you are hearing is so loud as to be embarrassing and annoying, I suggest that it is not the CPS valve. Sounds more likely to be valve lifters, but that's only a guess.

Bill B.
No it’s not a supercharged engine, I have a 2008 first edition with the 6.1 with 12000 miles on it so definitely not the valve lifters it ticks like a bastard for about a minute or so every time at cold start. There’s got to be a way to quiet it down.
 

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2016 Dodge Challenger R/T Plus in Granite Crystal Metallic
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No it’s not a supercharged engine, I have a 2008 first edition with the 6.1 with 12000 miles on it so definitely not the valve lifters it ticks like a bastard for about a minute or so every time at cold start. There’s got to be a way to quiet it down.
Get the SRT filter, like the others. I plan on doing the same as I had a similar experience to you, but only once.
 

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I think this discussion is leaning toward the source of the noise being oil related, as it can take some time for the oil to get up and flowing, the bearings and lifters can tick pretty bad for several seconds upon cold start.

However, to follow up on the CPS thing, I found a YouTube video showing the CPS valve on the 2008/09 6.1L engine. It's very close to the same location as the 5.7L and is sitting in plain site near the firewall, off to your left as you open the hood.
Also found pics of the replacement valve, not expensive apparently, here.
Watch these...
How to: Remove the Evap Purge Valve from a 2009 Dodge Challenger SRT-8
How to: Install New Evap Purge Valve on a 2009 Dodge Challenger SRT-8
Bill B.
 

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I think this discussion is leaning toward the source of the noise being oil related, as it can take some time for the oil to get up and flowing, the bearings and lifters can tick pretty bad for several seconds upon cold start.

However, to follow up on the CPS thing, I found a YouTube video showing the CPS valve on the 2008/09 6.1L engine. It's very close to the same location as the 5.7L and is sitting in plain site near the firewall, off to your left as you open the hood.
Also found pics of the replacement valve, not expensive apparently, here.
Watch these...
How to: Remove the Evap Purge Valve from a 2009 Dodge Challenger SRT-8
How to: Install New Evap Purge Valve on a 2009 Dodge Challenger SRT-8
Bill B.
Thank you very much, I’m going to change that little bastard ASAP
 

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Get the SRT filter, like the others. I plan on doing the same as I had a similar experience to you, but only once.
I did use an SRT filter on my oil change previous to my last change I’ve got a Mobil 1 on there now, I’m almost positive it made the same noise with the SRT filter though. I’m pretty convinced it’s more the clicking noise of something other than the motor itself.
 

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2016 Dodge Challenger R/T Plus in Granite Crystal Metallic
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I have three Hemi powered vehicles. All have a slight tick upon start up, but dissipates shortly afterwards. The better filter can't hurt, especially for a few dollars more.
 

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My 2019 6.4L ticks every time it starts too. Best oil filter, full synthetic 0W-40, still does it. It kinda bothers me that the ECU revs it up so high immediately because that's the worst possible time to do so, before the oil gets into everything. And I'm definitely talking about engine ticking, not the CPS valve. Engine ticking is louder and obviously changes frequency according to RPM. The CPS ticking is a constant frequency. It may stop as you hit the gas and resume after the engine goes back to a steady RPM, moving or not.

Bill B.
 

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My 2019 6.4L ticks every time it starts too. Best oil filter, full synthetic 0W-40, still does it. It kinda bothers me that the ECU revs it up so high immediately because that's the worst possible time to do so, before the oil gets into everything. And I'm definitely talking about engine ticking, not the CPS valve. Engine ticking is louder and obviously changes frequency according to RPM. The CPS ticking is a constant frequency. It may stop as you hit the gas and resume after the engine goes back to a steady RPM, moving or not.

Bill B.
Yeah that’s exactly why I think mine is the CPS thing it stays ticking after engine idle comes down with no change in loudness and then stops after a minute or so it’s just so goddam annoying and embarrassing if you start it up say at a car show or something.
 

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And mine has actually been getting louder and louder since I bought it about 4 years ago, I think I’m just gonna put a new one in and hopefully it stops god knows I’ve got plenty of time on my hands now with this virus thing shutting me down for who knows how long WTF !!!
 

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Anyone on here that needs any floor covering work done in RI let me know I’ve got plenty of time to do it now with all the retailers I work for closed up for a while, thank god my wife is benefiting from this thing being that she is employed by the department of health and has been working day and night since this whole thing erupted. Looks like she’ll be paying all of our bills soon.
 

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My 2019 6.4L ticks every time it starts too. Best oil filter, full synthetic 0W-40, still does it. It kinda bothers me that the ECU revs it up so high immediately because that's the worst possible time to do so, before the oil gets into everything. And I'm definitely talking about engine ticking, not the CPS valve. Engine ticking is louder and obviously changes frequency according to RPM. The CPS ticking is a constant frequency. It may stop as you hit the gas and resume after the engine goes back to a steady RPM, moving or not.

Bill B.
The engine revving up at start is important and in fact vital for engine longevity.

It ensures the gear oil pump primes.

The oil is already "into" everything. The elevated engine RPMs causes the residual oil to form a hydrodynamic bearing which prevents metal to metal contact until the oil from the gear pump arrives, which it does in very little time thanks to the elevated RPMs at cold start.
 

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The engine revving up at start is important and in fact vital for engine longevity.

It ensures the gear oil pump primes.

The oil is already "into" everything. The elevated engine RPMs causes the residual oil to form a hydrodynamic bearing which prevents metal to metal contact until the oil from the gear pump arrives, which it does in very little time thanks to the elevated RPMs at cold start.
Wow good to know
 

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Discussion Starter · #37 ·
Hi ChaseNeil, We see that you have received some great advice from your fellow forum members! However, if these suggestions do not address your concern and you decide to visit your dealer, our team would be happy to offer additional assistance throughout that process! We are available via private message!
Rob
DodgeCares
Hey team, so I have given up on the ticking noise as every dealership has told me that it is normal or that they don’t hear it. But now that it’s starting to get cold again I am hearing it mor often again.
 

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Hey team, so I have given up on the ticking noise as every dealership has told me that it is normal or that they don’t hear it. But now that it’s starting to get cold again I am hearing it mor often again.
Cold weather is when the CPS valve makes the loudest noise. The armature that moves has a small rubber tip that gets harder at lower temps so it clicks more loudly. There's nothing you can do about it. Don't be tempted to disconnect it. The fuel containment system absolutely must purge the canister that catches fuel vapor while not running. The company that I have worked for, for the past 25+ years, makes them and they definitely do know about the noise issue and customers past and present all complain about it. They're always playing with resistors and diodes connected across the coil to reduce the noise. The problem is that if you add such a diode across the coil, it will make it more quiet but it'll also shift the flow characteristic so much that it might throw a fault. Such valves are manufactured by Continental, now Vitesco, Bosch, and some others I'm not familiar with. In the past also Siemens and Siemens VDO.

All I can suggest is leave it alone and turn the music up.

Bill B.
 

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So I have a 2016 challenger Scat Pack with about 30K miles on it. I’ve owned it for about a week but the other day it’s started ticking. Sometimes it’s noticeable and sometimes is not but last night
I could hear it from inside the car while driving coming from the passenger side. Especially during acceleration. I’m just trying to figure out is this normal for the scat packs or is something wrong?
How does the motor sound with cold start and you immediately put the car in gear? I had a 2014 5.7 Charger with only about 10,000 miles that had a loud tick. I had an excellent service manager Tony Lopez at Crown Dodge in Ventura CA that I reported problem to. The first time I talked to him about it he kind of. shrugged it off. The next time I came in and complained he told me to bring the car in and leave it overnight. I instructed him to put the auto trans in gear when motor is started cold. The next day he called me an said they were going to pull and replace all valve lifters. With my 2018 5.7 Charger I let the motor run for about 30 seconds after cold start before I put it gear. The ticking is slight.
 

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The engine revving up at start is important and in fact vital for engine longevity.

It ensures the gear oil pump primes.

The oil is already "into" everything. The elevated engine RPMs causes the residual oil to form a hydrodynamic bearing which prevents metal to metal contact until the oil from the gear pump arrives, which it does in very little time thanks to the elevated RPMs at cold start.
I agree, especially if you let the motor idle in park for about 30 seconds after cold start.
 
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