CAT 3126 with a nasty GROWL

[Native]

Originally Posted by EastCoastCB

It seemed like it was coming from the front half of the bus but honestly with those kinds of frequencies its near impossible to tell where its coming from. Its louder than anyone's imagining.

I have not walked the bus while driving, of course, but it sounds like it is coming from the engine compartment to me. I had the opportunity to ride in the "navigator" seat right after the tires were replaced (which was right after the video was recorded) and it does seem to be forward of both the navigator and the driver. I believe I can hear/feel itmore in the driver seat. My wife was in the third seat (about 6 feet behind the driver seat) and she said it was loud and could not determine anything else (she has poor sound discrimination).


So what we know at this point is:
- Growl happens between 1800 RPM and 2150 RPM, epecially when loaded.
- BlueFire indicates 100% load and 100% Torque during the growl.
- It smooths out by 2200 RPM and has decent acceleration up through 2500 RPM.
- It is very smooth and ultra quiet at 45 MPH [1600 RPM in 5th (overdrive)]
- The growl seems to emanate from the engine compartment.
- There is some differential hum.
- The driveshaft appears to be aligned and *should* be balanced.
- It does this even with new tires all around.
- The motor mounts look good.
-The engine seems to lack the power it had two years ago.

- I seem to remember the growl happening in 4th when running through 1800-2150 RPM, but I will verify this shortly.

[EastCoastCB]

Mine only has a 3.42 rear and I'm always in the rpm range you're getting the noise in so I don't think its just the sound of lugging the engine.
But mine isn't nearly as heavy and has never had the kinds of weight in it yours has. Also mine won't go over 2400 rpm at all as far as I can tell.

To hear the video I posted you'll need a subwoofer of some sort. Mine's only a six inch mini sub but it works enough to hear the frequencies. You won't hear much at the beginning as the really low frequencies are too low to pick up much by us. Genreally thats 20hz or less. YOu probably already know this.

[Native]

Originally Posted by EastCoastCB

Mine only has a 3.42 rear and I'm always in the rpm range you're getting the noise in so I don't think its just the sound of lugging the engine.
But mine isn't nearly as heavy and has never had the kinds of weight in it yours has. Also mine won't go over 2400 rpm at all as far as I can tell.

To hear the video I posted you'll need a subwoofer of some sort. Mine's only a six inch mini sub but it works enough to hear the frequencies. You won't hear much at the beginning as the really low frequencies are too low to pick up much by us. Genreally thats 20hz or less. YOu probably already know this.

You have an AT545 which is non-locking. Cadilackid showed that his RedByrd will growl when lugged with a locked torque onverter but will not when it is unlocked.


I have another video that shows it (to a smaller degree) doing it in 4th and smooth up to about 54 MPH in 4th. I am working on uploading it now and will post as soon as I can.

[EastCoastCB]

Right on.

[Native]

This video was taken yesterday. The total vehicle weight at the time of the run was 23,740 pounds. We were driving an uphill grade and the transmission was in D (4th as a max gear). The growl is quite reduced in comparison to when it occurs in overdrive, however it is still there at 1800-2150 RPM ... 40 MPH to 45 MPH roughly. I also ran it up to 54-55 MPH in 4th (2500 RPM) to show that there was no growl.


Note the action of the boost pressure through the lower gears and into 4th. It seems to me to be acting irratically.


https://youtu.be/J9VyySGkfIM

[cadillackid]

I can hear the growl sounds in my Bose headsets... accelerates nicely and builds boost nicelyt when the RPMs go up.. yours acts a bit different than mine, your computer holds the engine load factor down a bit and doesnt allow it to peg... to me it doesnt sound bad... the boost did jump a little but also did the engine load factor at the same time.. so the computer hit some threshold that allowed it to fuel heavier and ran up the boost as it should.. pulling 22-24 lbs of boost at peak Horsepower is normal... it sounds pretty healthy keeping it in 4th... if it went to 5th at max RPM./ im guerssing you'd lose speed and RPM slowly on the climb which whould be Lugging at that point..
-Christopher

[cadillackid]

Love the dash you created on your Bluefire.. i need to get off my butt and finish mine so i can see my HPOP data
-Christopher

[Native]

Originally Posted by cadillackid

I can hear the growl sounds in my Bose headsets... accelerates nicely and builds boost nicelyt when the RPMs go up.. yours acts a bit different than mine, your computer holds the engine load factor down a bit and doesnt allow it to peg... to me it doesnt sound bad... the boost did jump a little but also did the engine load factor at the same time.. so the computer hit some threshold that allowed it to fuel heavier and ran up the boost as it should.. pulling 22-24 lbs of boost at peak Horsepower is normal... it sounds pretty healthy keeping it in 4th... if it went to 5th at max RPM./ im guerssing you'd lose speed and RPM slowly on the climb which whould be Lugging at that point..
-Christopher

On that climb, it would loose speed and RPM in 5th only if the RPMs were below 2200 RPM. If I were to hit that hill at 65-68, it would EVENTUALLY slow down, but not before the crest. It does have real heart over 2200 RPM.


Thank you for the examination of the data. That is what I have been thinking, but a second set of eyes and ears helps one make the decision to run with it or not. I still plan to lighten up on the accelerator when it drops below 2200 RPM and get back to speed once the hill is crested. That seemed to work out fine on the trip to Florida and back.

[Native]

Originally Posted by cadillackid

Love the dash you created on your Bluefire.. i need to get off my butt and finish mine so i can see my HPOP data
-Christopher

Thank you! My wife says I need to make the dials bigger. She is right there.


My Freightliner does not send out the HPOP data in native mode. Perhaps if I got the SDK and programmed my own I could pull that data. As you can see, even the oil temperature and exhaust temperature are dead in the display (lower right two guages). The BlueFire adapter *can* read that sort of data, but it does not come across the J1939 bus on this beast.

[cadillackid]

the datas is there but likely is a Request-only PID.. and I asked the bluefire people about adding it to the iPAD app methods for requesting individual PID's thast arent sent in the normal stream. and they were like.. sorry no time soon.. Grrr. but when I looked at the SDK the ability to request PID's is part of the API. and it works..



is your CAT running J1939 ? I thought most were J1708 at the diag connector and J1939 to the transmission..



when im climbing hills i drop to 4th gear and run it close to rated power (2300-2400 RPM). most times off the throttle a little.. sometimes ill be punched. but doing that i may run a little slower however my EGTs are much lower due to the increased boost.. and if its hot weather that means my engine fan spins faster so I never over-temp
-Christopher

[Native]

Originally Posted by cadillackid

the datas is there but likely is a Request-only PID.. and I asked the bluefire people about adding it to the iPAD app methods for requesting individual PID's thast arent sent in the normal stream. and they were like.. sorry no time soon.. Grrr. but when I looked at the SDK the ability to request PID's is part of the API. and it works..

That is what I thought, but have no time right now to look deeper into it. I have about 4 more trips to get our stuff moved, then there is selling the house, etc.

Originally Posted by cadillackid

is your CAT running J1939 ? I thought most were J1708 at the diag connector and J1939 to the transmission..

I have to have both J1939 and J1708 turned on to get the data I need. Some of the engine data comes from each.

Originally Posted by cadillackid

when im climbing hills i drop to 4th gear and run it close to rated power (2300-2400 RPM). most times off the throttle a little.. sometimes ill be punched. but doing that i may run a little slower however my EGTs are much lower due to the increased boost.. and if its hot weather that means my engine fan spins faster so I never over-temp
-Christopher

Good point. I do not have any real hills along the route, so I have not had to drop down.

[Native]

Merry Christmas everyone!


We are due to head out in a few hours on another TX to FL trip with another load. Thank you all for your input on this matter.

[Ronnie]

Merry Christmas !! Have a safe trip.

[EastCoastCB]

Originally Posted by Native

Merry Christmas everyone!


We are due to head out in a few hours on another TX to FL trip with another load. Thank you all for your input on this matter.

Yall have a safe and happy drive back to the Sunshine State!

And have a very merry Christmas!

[cadillackid]

Merry Christmas!!! and safe travels!. I had thought about Fliorida for christmas.. however in oghio a streak of days sunny and 50s is nice enough for me to stick around here then head south when the snow flies.
-Christopher

[EastCoastCB]

Originally Posted by cadillackid

Merry Christmas!!! and safe travels!. I had thought about Fliorida for christmas.. however in oghio a streak of days sunny and 50s is nice enough for me to stick around here then head south when the snow flies.
-Christopher

Do you have a Christmas display in your yard this year? Me n Roxy always love to see what you create.

[cadillackid]

I do and am still working on it.. right now its 100% 1950s-70s C9 lights except for the spots on the house.. but im stepping it up a notch with some animation tonight.. I'll get some pics..



I slowed down a bit on decorating, take the time with warm weather to FINALLY install my Webasto in the redByrd.. its in and plumbed, i just need to finish the fuel and wire it.. the paper in the box says I bought it 3 years ago brand new in box for $250. (SCORE!!)..

[Native]

Thank you all for al of your well wishes. We made it to Florida, unloaded, and headed back. We were able to spend Christmas dinner with family, so that was a bonus.


The Beast ran well, as long as I avoided the GROWL speeds. That was pretty easy to do. She likes to run at 69 MPH (2400 RPM) and gets very quiet there. We are getting around 8 MPG. That's not too shabby for a 38' retired school bus. The new RoadMaster 11R22.5's perform so well. It is much quieter and the ride does seem to be a bit smooher.

[EastCoastCB]

Glad all is well and you had a nice Christmas!

[Native]

Here is a little update.


We took The Beast to a local CAT dealer (Holt Cat) for a PM. It had 7000 miles put on it since the last one so it was time. The mechanic said he only heard the engine moan ... no growl. He also said he was not familiar with how a bus should sound. He did not hear anything problematic.


The CAT ET program and test suite did find:
- The secondary engine timing sensor was throwing an intermittent fault
- The secondary engine timing sensor was showing no readings at times
- The injector pressure sensor (which I replaced a year ago) was showing low voltage intermittently.
- The sensor wiring harness has micro-fissures which show up as intermittent shorts


I was not "sold" on the diagnosis, nor their prices. I found the harness and sensors for about a third of the cost t the Freightliner dealer!


Interesting to note that the growl is now subdued after the oil was changed. I can cruise on level ground (or a very slight incline) at 58 MPH in overdrive (smack dab in the middle of the GROWL zone) and only hear elevated engine noise, not the heavy reverberations. Of course this is with the vehicle empty of all cargo. I also noticed that while cruising on level ground, the %load and %torque on the BlueFire screen reads lower than before ... about 50% to 60% as opposed to just about 100% before.


I am thinking that part of the problem may have been induced by my adding Lucas Oil Treatment some time after the first PM ... maybe 1000 miles after the first PM. I am thinking the injectors and HEUI system did not like the effect of the Lucas Oil Treatment. Thoughts?