PCM Diagnostics & Tuning HP Tuners | Holley | Diablo
Sponsored by:
Sponsored by:

Initial startup rpm drop after cam.

Thread Tools
 
Search this Thread
 
Old 07-02-2005, 07:47 AM
  #1  
TECH Senior Member
Thread Starter
iTrader: (4)
 
GuitsBoy's Avatar
 
Join Date: Apr 2003
Location: Long Island, NY
Posts: 6,249
Received 3 Likes on 3 Posts

Default Initial startup rpm drop after cam.

Hi all.

What table do i need to change to fix my initial drop in RPMs after startup? Its kind of a surge, but it evens out after just a couple seconds.

With a stock motor, the rpms hang high for a couple of seconds until it settles down to its idle speed vs ECT. Id like to get this back.

Thanks,
-Tony
Old 11-13-2005, 09:25 AM
  #2  
Moderator
iTrader: (4)
 
JNorris's Avatar
 
Join Date: Nov 2001
Location: Montgomery, AL
Posts: 2,074
Likes: 0
Received 0 Likes on 0 Posts

Default

I am having the same problem. Did you ever get this solved?
Old 11-13-2005, 09:54 AM
  #3  
TECH Senior Member
Thread Starter
iTrader: (4)
 
GuitsBoy's Avatar
 
Join Date: Apr 2003
Location: Long Island, NY
Posts: 6,249
Received 3 Likes on 3 Posts

Default

Yeah, its mostly in tuning the RAF and the effective IAC area. Also, leaning out the OLFA table helped a bit with my cold start surging.
Old 11-13-2005, 10:48 AM
  #4  
TECH Fanatic
iTrader: (1)
 
SmokingWS6's Avatar
 
Join Date: Jun 2004
Location: St. Louis MO
Posts: 1,795
Likes: 0
Received 2 Likes on 1 Post
Default

Reducing or deleting afterstart enrichment will cure a lot of the chugging and idle drops after startup. AE acts somewhat like a choke that slowly drop off after cranking, however for most cam setups it dumps in to much fuel.
Old 11-13-2005, 11:46 AM
  #5  
TECH Addict
 
Another_User's Avatar
 
Join Date: Feb 2004
Posts: 2,826
Likes: 0
Received 0 Likes on 0 Posts
Default

If your fueling is right, then you may want to look closely at your running airflow table and your iac park position settings. If you IAC park position is too high then you should see something similar to what you described. If it were a running airflow problem your startup surge would likely be accompanied by other driving issues like "cruise control" feel.
Old 11-14-2005, 07:00 AM
  #6  
Moderator
iTrader: (4)
 
JNorris's Avatar
 
Join Date: Nov 2001
Location: Montgomery, AL
Posts: 2,074
Likes: 0
Received 0 Likes on 0 Posts

Default

Thanks guys.

John
Old 11-14-2005, 07:22 AM
  #7  
TECH Fanatic
 
SideStep's Avatar
 
Join Date: Mar 2003
Posts: 1,942
Likes: 0
Received 1 Like on 1 Post

Default

Originally Posted by SmokingWS6
Reducing or deleting afterstart enrichment will cure a lot of the chugging and idle drops after startup. AE acts somewhat like a choke that slowly drop off after cranking, however for most cam setups it dumps in to much fuel.
Good info... I do not have the above problem but I do have a rich smell just at start-up.

Old 11-15-2005, 07:48 AM
  #8  
Moderator
iTrader: (4)
 
JNorris's Avatar
 
Join Date: Nov 2001
Location: Montgomery, AL
Posts: 2,074
Likes: 0
Received 0 Likes on 0 Posts

Default

Last night I played with the effective IAC area table and the ECT after start enrichment table and got most of my problem solved.
I still need to fine-tune the RAF and IAC park position tables.

Thanks for the help guys.


John
Old 11-16-2005, 01:18 AM
  #9  
Var
On The Tree
iTrader: (1)
 
Var's Avatar
 
Join Date: Jul 2005
Posts: 178
Likes: 0
Received 0 Likes on 0 Posts
Default

http://redhardsupra.blogspot.com/200...le-tuning.html



Quick Reply: Initial startup rpm drop after cam.



All times are GMT -5. The time now is 05:15 PM.