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Old 01-16-2025, 10:29 AM   #1
Mini-Skoolie
 
Join Date: Aug 2023
Posts: 16
Engine Noise at startup

Noise at startup

I’m getting this engine noise after my DT466 engine completes its start up test cycle. I don’t get this noise if it’s above freezing or after initial start or using the engine block heater. I hope I’m not damaging something by starting it . I’m heading into colder climates so I need to figure this out.

You can review the video clip here. The noise starts at 13 seconds:

https://youtu.be/dQJynbTyrjk?si=6PIrWxMKiXQBR15



Thank you in advance!

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Old 01-16-2025, 01:57 PM   #2
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Location: Central Tx.
Posts: 2,505
Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
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Originally Posted by Cannabus View Post
Noise at startup

I’m getting this engine noise after my DT466 engine completes its start up test cycle. I don’t get this noise if it’s above freezing or after initial start or using the engine block heater. I hope I’m not damaging something by starting it . I’m heading into colder climates so I need to figure this out.

You can review the video clip here. The noise starts at 13 seconds:

https://youtu.be/dQJynbTyrjk?si=6PIrWxMKiXQBR15



Thank you in advance!
That is one weird noise!
Only does it below freezing ?
Engine off, not running?


My first uneducated guess would be to take a look at the turbo actuator, is is stuck or maybe loose ???

Can you pinpoint where the noise is coming from ?
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Old 01-16-2025, 02:17 PM   #3
Mini-Skoolie
 
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It does sound like it’s coming from the Turbo Actuator area. Hard to pinpoint. That’s before starting the engine just after gauge panel goes through test sequence and the glow plugs wait light is on. There’s also a Chech Engine light that goes out once started.

Thanks I’ll check the TA for tightness
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Old 01-17-2025, 07:20 AM   #4
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Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
the initial 2 click clunks I thought were the turbo actuator cycling...



the rumble at the end sounds almost like a relay trying to come on that cant so its buzzing.. is there an intake heater on it that may try to come on below freezing and its relay is no good so would rattle like that?
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Old 01-17-2025, 11:21 AM   #5
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Originally Posted by cadillackid View Post
the initial 2 click clunks I thought were the turbo actuator cycling...



the rumble at the end sounds almost like a relay trying to come on that cant so its buzzing.. is there an intake heater on it that may try to come on below freezing and its relay is no good so would rattle like that?
I wood for sure check on the relays, great suggestion.
In my experiences I have neer heard a 12 car relay buzz that loud. They eiter short out or open up?
I have heard and seen large industrial contactors do that but smaller relays...., would be a first for me...but yes...needs to be looked at.

Question: can the servo motor react violently to a bad relay, causing that much noise?
Upon initial post test, actuator cycles, relay heats up and goes spastic triggering servo motor to react ???
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Old 01-17-2025, 03:17 PM   #6
Mini-Skoolie
 
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Thanks I’ll look into that
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Old 01-17-2025, 03:49 PM   #7
Bus Geek
 
Join Date: May 2009
Location: Columbus Ohio
Posts: 20,057
Year: 1991
Coachwork: Carpenter
Chassis: International 3800
Engine: DTA360 / MT643
Rated Cap: 7 Row Handicap
Quote:
Originally Posted by ewo1 View Post
I wood for sure check on the relays, great suggestion.
In my experiences I have neer heard a 12 car relay buzz that loud. They eiter short out or open up?
I have heard and seen large industrial contactors do that but smaller relays...., would be a first for me...but yes...needs to be looked at.

Question: can the servo motor react violently to a bad relay, causing that much noise?
Upon initial post test, actuator cycles, relay heats up and goes spastic triggering servo motor to react ???

the turbo actuator if i remember right is on a PWM output as its variable.. a relay would be open or close..


generally if a DC relay chatters its usually a faulty wiring connection where the actual Source power for the coil is the same as the contact (even if indirectly)...


so say you have a heater where a large wire comes out, splits in 2.. one side goes t oa fuse and to the Contacts on the relay.. the other goes through a fuse and to the coil on the relay.. the computer grounds the other side of the coil to energize the relay..



a poor connection would drop the voltage on both the contact and the coil significantly.. possibly enough that the coil would drop out.. instantly the voltage goes back up so the coil pulls back in... at the same time it may be staying on long enough to start warming the heater.. as a resistance heater warms it oulls less current so therefore less voltage drop.. and at some point the relay stays on... just giving an example.. no idea if thats what happening.. just surmising because this only happens when its cold out and the engine is cold (no block heater use).. from what i remember the intake heater on the DT466E is temperature dependent and not an always-used item like the glowplugs in the T444E are..
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Old 01-17-2025, 05:58 PM   #8
Mini-Skoolie
 
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Thanks. Thats a lot to absorb. I’ll have some studying up to do.
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Old 01-17-2025, 09:59 PM   #9
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Join Date: May 2015
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Year: 1999
Chassis: Amtran / International
Engine: DT466E HT 250HP - Md3060
Cannabus, could you please fill out your profile so we all could know what year/make and model bus you got. Thanks....


I am uploading here for you a simplified wired diagram for a 2004+ Dt466e motor.
With this it will help you better understand how the VGT control module and the Inlet Air Heater element communicate.

I would first try cadillackid's advice, pull out both relays for the air intake heaters, turn the key on and see if the noise goes away. If it does then you know where the issue is.

If nothing else at least you now have an engine wiring diagram.


International ELECTRONIC CONTROL SYSTEM DIAGNOSTICS
Beginning of 2004 Model Year DT 466, DT 570, and HT 570
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