Page 1 of 3 123 LastLast
Results 1 to 10 of 21

Thread: New CAM and Idle Assistance

  1. #1
    Senior Member Behold's Avatar
    Join Date
    Apr 2010
    Posts
    155

    Default New CAM and Idle Assistance

    I have just fitted a new cam. Its quite a large cam so its affected the running a lot. It runs fine, little lean nothing an AutoVE will not sort out.

    I am trying to sort the idle out.

    It will idle and holds at 800 as expected but after a rev or slow down from speed. I have sorted out the fueling in the VE for idle and this has helped a lot. but I assume I need to sort out the spark table. it ticks over at 65-68KPA should I increase the spark to match similar to 30-35 ish. (27degrees I think).

    Which spark table is it? is it the Base Spark table. B5932 B5933?

    Anything else I need to think of?

    Also on start it really struggles with out any throttle. is this a fuelling issue or is this my throttle body needing a larger pilot hole?

    anything I should particularly log? I am starting to trawl the forums but any help would be good.
    -----------------------------------------------------------------------------------------
    Thanks Antony

    Holden Commodore GTS - LS1 5.7
    12 rib Crank Driven Vortech V2 Centri Charger (Intercooled) 9 PSI.
    LS6 Intake
    LS6 Heads
    YT 1.7 Roller Rockers
    BTR Dual Spring with Ti retainers
    BTR Hardend 7.400 Push rods
    Comp Cam JAMCAM
    2 Bar Map
    Mafless
    LS2 Coils

    PCM LS1B with 512KB Running COS5 v01290005

  2. #2
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    How big is the cam (indur/exdur lsa +adv)...?

  3. #3
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Quote Originally Posted by Behold View Post
    ...
    Which spark table is it? is it the Base Spark table. B5932 B5933?
    ...
    Yes, base spark in G and in P/N.

  4. #4
    Senior Member Behold's Avatar
    Join Date
    Apr 2010
    Posts
    155

    Default

    the cam is

    282/294 (230/242@/.5)
    LSA 115 and +2 Advance

    I made some changes. Throttle Cracker and startup airflow correction tables. and the idle learning to 4.3. and It certainly runs a lot better than it did. it starts and idles well with a nice sound to tick over. on a spirited stop it does drop to 2-400 RPM and may not always recover unless I blip the throttle.

    could it be its struggling air? or should I be looking at leaning it out a bit more. currently its bang on 14.7 AFR

    I have not touched the spark yet.
    -----------------------------------------------------------------------------------------
    Thanks Antony

    Holden Commodore GTS - LS1 5.7
    12 rib Crank Driven Vortech V2 Centri Charger (Intercooled) 9 PSI.
    LS6 Intake
    LS6 Heads
    YT 1.7 Roller Rockers
    BTR Dual Spring with Ti retainers
    BTR Hardend 7.400 Push rods
    Comp Cam JAMCAM
    2 Bar Map
    Mafless
    LS2 Coils

    PCM LS1B with 512KB Running COS5 v01290005

  5. #5
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    230/242 115 +2

    this cam has 6* overlap, so maybe bump desired idle speed to 900 rpm.

    Yes, maybe try more desired air.

    What intake manifold and throttle body do you have...?


    How are you determining the AFR (wideband...?)...?
    Generally, as overlap increases, at idle, wideband will tend to read leaner (unburnt fuel and oxygen passing thru), so yes try going a bit leaner that what you see.
    If you don't have catalysts, try to see if you can smell unburnt fuel in the exhaust, this will tell you if it's not lean.

  6. #6
    Senior Member Behold's Avatar
    Join Date
    Apr 2010
    Posts
    155

    Default

    Sorry for the delayed reply.

    So it's a LS6 intake and ls1 TB. I have followed the tutorials and played around with settings. The RAFIG table is tuned and spark bumped up.

    It idles a bit better but still stalls coming off throttle or after blipping. It actually idles really smooth at 800-850-900 and 950.

    So I'm lost. Do I just need more air in on idle. Do I ream out the blade hole? If so how much at a time? File it or drill it?

    It's the most annoying bit. Any load as well can cause it to die. Often the spark is stable. And at 500rpm can recover. But often drops to 1-200. If I get on the throttle it will catch and stay running.
    -----------------------------------------------------------------------------------------
    Thanks Antony

    Holden Commodore GTS - LS1 5.7
    12 rib Crank Driven Vortech V2 Centri Charger (Intercooled) 9 PSI.
    LS6 Intake
    LS6 Heads
    YT 1.7 Roller Rockers
    BTR Dual Spring with Ti retainers
    BTR Hardend 7.400 Push rods
    Comp Cam JAMCAM
    2 Bar Map
    Mafless
    LS2 Coils

    PCM LS1B with 512KB Running COS5 v01290005

  7. #7
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Quote Originally Posted by Behold View Post
    ...

    It idles a bit better but still stalls coming off throttle or after blipping.

    ...
    This sounds like Throttle Follower...

  8. #8
    Lifetime Member
    Join Date
    Dec 2014
    Posts
    230

    Default

    What is the IAC holding at when at normal idle no load? Sounds like there isn't enough base airflow. On DBC the IAC is there to help control Idle not totally control, I mean its there to ramp in and out of idle. It can not do that quickly so there has to be proper base air. I deal a lot with off road race, huge loads at idle and have come up with my own method for the cars running well down low and not dying. I get enough airflow so when there is no load the last bit of idle RPM is spark trimmed. So when load is placed spark returns and air can be added by IAC as it is needed. The way I see it all base engine load has to be taken care of without idle air trim.

    This is what I deal with. They go from all out....


    To technical rock crawling. Here is a shot of the steering setups that draw massive parasitic load down low.


    That one had a bad day. DOM housing didnt like the skying out. LOL. These were both from an event I was at in China the past 3 weeks, babysitting 10 cars.

    Plenty of other examples in HERE.
    Last edited by ProperTuningOG; October 17th, 2016 at 02:33 AM.

  9. #9
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Your pics are not showing up...

  10. #10
    Lifetime Member
    Join Date
    Dec 2014
    Posts
    230

    Default

    Quote Originally Posted by joecar View Post
    Your pics are not showing up...
    Really, they show up fine with all devices logged in and out here. Country issue?

Page 1 of 3 123 LastLast

Similar Threads

  1. New cam - rich idle??
    By Tomcat in forum Gen III V8 Specific
    Replies: 18
    Last Post: May 13th, 2008, 07:38 AM
  2. crazy idle cam only Ls1
    By Ls1_Rulz in forum Gen III V8 Specific
    Replies: 6
    Last Post: February 26th, 2008, 05:25 AM
  3. C.o.m.e racing cam idle settings
    By JCA in forum General (Petrol, Gas, Ethanol)
    Replies: 12
    Last Post: September 21st, 2007, 11:29 PM
  4. Large cam idle help
    By VHR in forum Gen III V8 Specific
    Replies: 6
    Last Post: December 6th, 2006, 02:26 PM
  5. Idle learn after cam install
    By minytrker in forum General (Petrol, Gas, Ethanol)
    Replies: 5
    Last Post: April 5th, 2006, 04:27 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •