Sponsored

Sound Coming from Master Cylinder/Firewall Region

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
I have an odd fluttering/flapping sound coming from the master cylinder/firewall region heard only from inside the cab. This sound is intermittent when in gear, at a stop/idle. It is sometimes subtle, and sometimes very apparent. At first I thought something was loose inside the dash, but this sound only during idle or coming to a stop (under 5mph). Any thoughts?? I will be posting a video soon.
Sponsored

 

NachoRuby

Well-Known Member
First Name
Chad
Joined
Apr 28, 2021
Threads
28
Messages
2,985
Reaction score
4,395
Location
Pennsylvania
Vehicle(s)
'21 JTR , '18 JLU, 73 VW Bug, 97 VW Jetta, all MTs
Auto or manual? Brake master cylinder or clutch master cylinder?
 
OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
You can here the “flutter” sound each time I shift into D. Again, sound is coming from drivers side dash. Use link if you cannot see vide.
 

Attachments

Last edited:

Ball_Ze

Well-Known Member
First Name
Scot
Joined
Oct 9, 2021
Threads
0
Messages
107
Reaction score
183
Location
Canton, MI
Vehicle(s)
22 JTR, 17 AR4C, 19 CT6-V
Occupation
engineer
Look underhood for all of your evap system routing - there will be a bright green cap over a schrader valve somewhere in the tubing. Trace the tubing and see if any of it goes to an electric solenoid on your firewall. Could be the evap purge solenoid is mounted there (maybe?) and you're hearing it while your evap system is being purged.
 

Sponsored

OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
Look underhood for all of your evap system routing - there will be a bright green cap over a schrader valve somewhere in the tubing. Trace the tubing and see if any of it goes to an electric solenoid on your firewall. Could be the evap purge solenoid is mounted there (maybe?) and you're hearing it while your evap system is being purged.
I checked for anything in this area, and nothing. It almost sounds like this sound is radiating upwards from the transmission area. Again this is only at idle or very low speeds (>5MPH), only in Drive.
 

Deleted member 22728

You'll not have an evaporative emissions on your model, as it is a diesel. In any case, try this: crank engine, place in drive. While applying the brake, tip-in the throttle just enough to come off idle, and see if the noise is still there. Do the same in reverse. What we're attempting to do is isolate if the powertrain (engine/trans/xfer case) vibration is causing the noise; in drive, the powertrain will "rock" one way, the opposite in reverse. As the diesel exhaust is located the opposite side (passenger) than the gas burner, the test might help you get a little closer to isolating the fault.
 

Ball_Ze

Well-Known Member
First Name
Scot
Joined
Oct 9, 2021
Threads
0
Messages
107
Reaction score
183
Location
Canton, MI
Vehicle(s)
22 JTR, 17 AR4C, 19 CT6-V
Occupation
engineer
You'll not have an evaporative emissions on your model, as it is a diesel. In any case, try this: crank engine, place in drive. While applying the brake, tip-in the throttle just enough to come off idle, and see if the noise is still there. Do the same in reverse. What we're attempting to do is isolate if the powertrain (engine/trans/xfer case) vibration is causing the noise; in drive, the powertrain will "rock" one way, the opposite in reverse. As the diesel exhaust is located the opposite side (passenger) than the gas burner, the test might help you get a little closer to isolating the fault.
Excellent point! I missed that it was a diesel! #facepalm
 
OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
After finding other threads in the wrangler forums, I found a topic of the DPF weld breaking off the transmission. In turn, causing a knocking sound. You can see a link to a video. The noise I’m experiencing is not that loud, but sounds identical (but I can hear mine emitting from the dash; upper left and behind the AC controls). See here:

https://www.jlwranglerforums.com/forum/threads/2021-eco-diesel-suddenly-much-louder.61174/

https://www.jlwranglerforums.com/forum/threads/transmission-tick-rattle-when-stopped.80735/
 
OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
You'll not have an evaporative emissions on your model, as it is a diesel. In any case, try this: crank engine, place in drive. While applying the brake, tip-in the throttle just enough to come off idle, and see if the noise is still there. Do the same in reverse. What we're attempting to do is isolate if the powertrain (engine/trans/xfer case) vibration is causing the noise; in drive, the powertrain will "rock" one way, the opposite in reverse. As the diesel exhaust is located the opposite side (passenger) than the gas burner, the test might help you get a little closer to isolating the fault.
Great point. I told it into the dealer, since I am still within the warranty period. They mentioned the DPF bracket weld is not broken or loose. They are at a dead stop. I will bring this to their attention. Thank you and I’ll let you know what they find!
 

Sponsored

OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
Great point. I told it into the dealer, since I am still within the warranty period. They mentioned the DPF bracket weld is not broken or loose. They are at a dead stop. I will bring this to their attention. Thank you and I’ll let you know what they find!
After placing it in drive (while hearing the noise), we brought the rpm’s up a bit. The noise goes away out of idle. They are still not sure what the cause is.
 
OP
OP
tmbstn21

tmbstn21

Member
First Name
Tyler
Joined
Nov 15, 2021
Threads
1
Messages
8
Reaction score
7
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator, Eco Diesel
All,
The dealer found the culprit! There are two fuel lines coming from the fuel pump, to the drivers side of the engine. There was a plastic retainer clip on the firewall that was loose. During certain idle speeds, there was just enough pressure from the pump causing these lines to vibrate against the firewall. The clip was tightened and secured. No more "flutter/flapping" noise. Hope this helps anyone experiencing the same problem.
 

Deleted member 22728

All,
The dealer found the culprit! There are two fuel lines coming from the fuel pump, to the drivers side of the engine. There was a plastic retainer clip on the firewall that was loose. During certain idle speeds, there was just enough pressure from the pump causing these lines to vibrate against the firewall. The clip was tightened and secured. No more "flutter/flapping" noise. Hope this helps anyone experiencing the same problem.
Awesome news, and many thanks for the feedback, which benefits the whole JT Eco community!
Sponsored

 
 



Top