1994.5 - 1997 7.3L Power Stroke Diesel  

Coasting Noise??

Thread Tools
 
Search this Thread
 
  #1  
Old 09-04-2008, 07:26 PM
1982_f150's Avatar
1982_f150
1982_f150 is offline
Senior User
Thread Starter
Join Date: Feb 2007
Location: Nanaimo B.C. Canada
Posts: 409
Likes: 0
Received 0 Likes on 0 Posts
Coasting Noise??

hey, i just bought a 1995 f250 PSD and i was wondering when you donw shift is the engine supposed to make noise or is it silent?
 
  #2  
Old 09-04-2008, 08:44 PM
c00nhunterjoe's Avatar
c00nhunterjoe
c00nhunterjoe is offline
Post Fiend
Join Date: May 2007
Location: oxford pa
Posts: 8,565
Likes: 0
Received 2 Likes on 2 Posts
diesel's are pretty noisy the last time i checked. i'm not following the question? our engines do have a function that when not under load the computer will limit fueling and the motors will get pretty quiet at times. is this what you are asking about?
 
  #3  
Old 09-04-2008, 10:45 PM
1982_f150's Avatar
1982_f150
1982_f150 is offline
Senior User
Thread Starter
Join Date: Feb 2007
Location: Nanaimo B.C. Canada
Posts: 409
Likes: 0
Received 0 Likes on 0 Posts
well when i down shift, and let out the clutch and the motor holds back, its silent. theres no diesel knock. then when i stop it starts to idle again or when i rev it up it will make noise. only when im coasting.
 
  #4  
Old 09-04-2008, 11:26 PM
kawa's Avatar
kawa
kawa is offline
Postmaster
Join Date: Jun 2007
Location: Rogue River, OR
Posts: 2,795
Likes: 0
Received 0 Likes on 0 Posts
Sounds like ya got one of those new fangled Electric/Diesel jobs

Rog
 
  #5  
Old 09-05-2008, 12:48 AM
RubberDuck's Avatar
RubberDuck
RubberDuck is offline
Logistics Pro

Join Date: Jul 2001
Location: Marble Falls, Texas
Posts: 4,137
Received 38 Likes on 28 Posts
Think about it like this.... Jody, DP-Tuner has a tune called drive through. It's all about the timing of the injection. When you let out of the throttle, but the motor is still holding say 2000 rpm. The injection timing is functioning at idle, not 2k. Now weather or not it's advanced or retarded, I couldn't tell you. But this is my best guess as far as an answer. But it is completely normal. Mine does it too.
 
  #6  
Old 09-05-2008, 07:23 AM
Mark Kovalsky's Avatar
Mark Kovalsky
Mark Kovalsky is offline
Fleet Owner

Join Date: Aug 1999
Location: SE Florida
Posts: 23,257
Received 1,576 Likes on 1,054 Posts
No, it isn't timing. It's decel fuel shutoff. When coasting there is no need for fuel, so to get better fuel economy the PCM shuts the fuel off. That's why there is no diesel knock, there is no fuel being burnt.
 
  #7  
Old 09-05-2008, 07:52 AM
Neal 97 250's Avatar
Neal 97 250
Neal 97 250 is offline
Post Fiend
Join Date: Mar 2007
Location: Johnson City, TN.
Posts: 9,010
Likes: 0
Received 2 Likes on 2 Posts
Yes it sounds like your diesel is normal.

Electric/Diesel, Kawa you are the bomb.
 
  #8  
Old 09-05-2008, 07:57 AM
Neal 97 250's Avatar
Neal 97 250
Neal 97 250 is offline
Post Fiend
Join Date: Mar 2007
Location: Johnson City, TN.
Posts: 9,010
Likes: 0
Received 2 Likes on 2 Posts
Wow I justrealized I hit 4000 posts just now. I think the HP fairy is heading my way. Mater of fact it will be here next weekend.


Clutch and H2E conuntdown: 7 days Me vewy happy

Sorry for the hijack, now back to our regularly schedued thread...
 
  #9  
Old 09-05-2008, 10:59 AM
1982_f150's Avatar
1982_f150
1982_f150 is offline
Senior User
Thread Starter
Join Date: Feb 2007
Location: Nanaimo B.C. Canada
Posts: 409
Likes: 0
Received 0 Likes on 0 Posts
haha, awsome. thx guys. im going to go out and make some smoke..
 
  #10  
Old 09-05-2008, 11:14 AM
secondarychaos's Avatar
secondarychaos
secondarychaos is offline
Posting Guru
Join Date: Feb 2008
Location: Grass Valley, CA
Posts: 1,526
Likes: 0
Received 0 Likes on 0 Posts
Does it completely shut off fuel or just limit it to almost nothing?
I've noticed that if i downshift and the engine goes above 1000 rpms, the EGT's will drop to about 200...
 
  #11  
Old 09-05-2008, 05:59 PM
tjbeggs's Avatar
tjbeggs
tjbeggs is offline
Post Fiend

Join Date: Apr 2004
Location: Silver Lake Dunes, MI
Posts: 12,835
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by Neal 97 250
Wow I justrealized I hit 4000 posts just now. I think the HP fairy is heading my way. Mater of fact it will be here next weekend.


Clutch and H2E conuntdown: 7 days Me vewy happy

Sorry for the hijack, now back to our regularly schedued thread...
Neal Congrats on 4K! That HP will come soon enough! I cleared the valley of my mock up engine. to start my turbo project but you are gonna beat me to it!
 
  #12  
Old 09-05-2008, 06:27 PM
Action4478's Avatar
Action4478
Action4478 is offline
Hotshot
Join Date: Aug 2006
Posts: 10,764
Received 34 Likes on 31 Posts
Originally Posted by tjbeggs
Neal Congrats on 4K! That HP will come soon enough! I cleared the valley of my mock up engine. to start my turbo project but you are gonna beat me to it!
TJ ,, you gots way too many projects any way....
 
  #13  
Old 09-05-2008, 07:01 PM
joe_13894's Avatar
joe_13894
joe_13894 is offline
Posting Guru
Join Date: Aug 2007
Location: The boonies by Dallas OR
Posts: 1,507
Likes: 0
Received 1 Like on 1 Post
Originally Posted by secondarychaos
Does it completely shut off fuel or just limit it to almost nothing?
I've noticed that if i downshift and the engine goes above 1000 rpms, the EGT's will drop to about 200...
Nope, no fuel at all above 1200 RPM. You should also note a "light idle" sound between 1200 RPM and actual idle where the engine is powering itself. It sounds noticeably less loud.

Fuel injected gassers do the same exact thing.... save for occasional bursts of fuel to keep the cat hot. I'd imagine the new DPF equipped trucks would have to do the same.
 
  #14  
Old 09-05-2008, 07:47 PM
tjbeggs's Avatar
tjbeggs
tjbeggs is offline
Post Fiend

Join Date: Apr 2004
Location: Silver Lake Dunes, MI
Posts: 12,835
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by Action4478
TJ ,, you gots way too many projects any way....
I consider shop time therapy!! HP is even better though!
 
  #15  
Old 09-05-2008, 10:25 PM
Neal 97 250's Avatar
Neal 97 250
Neal 97 250 is offline
Post Fiend
Join Date: Mar 2007
Location: Johnson City, TN.
Posts: 9,010
Likes: 0
Received 2 Likes on 2 Posts
Therapy... Hmmm I need some therapy
 


Quick Reply: Coasting Noise??



All times are GMT -5. The time now is 01:09 AM.