LS1TECH - Camaro and Firebird Forum Discussion

Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Misfire

Thread Tools
 
Search this Thread
 
Old 05-25-2017, 01:28 PM
  #1  
Registered User
Thread Starter
 
shane1618's Avatar
 
Join Date: May 2017
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default Misfire
I have a 2009 chevy 1500 5.3 4x4 z71
it is putting up a p0300 code and a p0304 code .
Cyl 4 i have 25 lb pressure . Could it be a broke valve spring ?
shane1618 is offline  
Reply Like
Old 05-25-2017, 01:31 PM
  #2  
TECH Senior Member
 
G Atsma's Avatar
 
Join Date: Jun 2016
Location: Central Cal.
Posts: 21,208
Received 3,147 Likes on 2,454 Posts
Default
Hearing any strange noises?
G Atsma is offline  
Reply Like
Old 05-25-2017, 01:33 PM
  #3  
Registered User
Thread Starter
 
shane1618's Avatar
 
Join Date: May 2017
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default
No i am not . I unpluged the coil and the injector cyl 4
shane1618 is offline  
Reply Like
Old 05-25-2017, 01:37 PM
  #4  
TECH Senior Member
 
G Atsma's Avatar
 
Join Date: Jun 2016
Location: Central Cal.
Posts: 21,208
Received 3,147 Likes on 2,454 Posts
Default
A broken spring would drop the valve a bit, but maybe not enough to hit the piston. Compression would be closer to zero if a valve was open a bit.
Look up the codes to see what they mean.
G Atsma is offline  
Reply Like
Old 05-25-2017, 04:11 PM
  #5  
Launching!
iTrader: (5)
 
nine8ss's Avatar
 
Join Date: Feb 2016
Location: Tucson, AZ
Posts: 253
Likes: 0
Received 2 Likes on 2 Posts
Default
Put a bit of oil in cyl 4 and see if the compression comes up a bit. If it does, you are looking at piston ring failure. Your next step should be a leakdown test.

PO300 is multiple misfire
PO304 is cyl 4 misfire
nine8ss is offline  
Reply Like
Back to Subforum
Generation III Internal Engine
View Next Unread
Help me identify these heads




Advanced Search
Quick Reply: Misfire


Reply Closed Thread Share

All times are GMT -5. The time now is 04:11 PM.