Page 2 of 2 FirstFirst 12
Results 11 to 15 of 15

Thread: cam/crank correlation with vortec dist?

  1. #11
    Senior Member
    Join Date
    Aug 2006
    Posts
    188

    Default

    I'd like to throw in a little experience here just to avoid confusion for the reader who may be reading this thread and thinking that distributor orientation has anything to do with ignition timing.

    Distributor orientation does not affect ignition timing.

    From both the service manual and experience with the 24x signal from a distributor (prototyping only), the PCM is monitoring the 24x crank signal to determine crankshaft position. However, this is not enough for the PCM to know when to fire the injectors/coils. The PCM uses the 1x cam signal to determine engine stroke (intake or exhaust). If no cam signal is present or the cam signal is not in proper orientation, the PCM will attempt to start the engine as long as it sees the 24x crank signal (engine rotation is present). If the engine does not start (no increase in RPMs), the PCM will assume opposite stroke in an attempt to start the engine (extended cranking and typically backfire).

    So don't get too caught up on the distributor orientation. Follow the instructions provided (as per GM) and expect reliable starts 100% of the time.

    There's nothing wrong with knowing for sure that the cam sensor orientation is 100% accurate...but GM does not reveal this information. Probably because it's not critical.

    Of the several vehicles already up and running with 24x, no one has had startup issues or DTCs indicating improper camshaft orientation.
    Last edited by S10Wildside; July 3rd, 2009 at 06:38 AM.
    24x LS1 PCM on Early Small-Block Chevy and LT1/LT4
    http://www.eficonnection.com

  2. #12
    Senior Member
    Join Date
    Oct 2005
    Posts
    174

    Default

    I am planning to convert an old inline-6 (292) Chevy to EFI. To keep the look as
    original as possible I prefer to keep the distributor. My plan is to install the 1x cam
    position sensor in the inline distributor and add a 3x crank reluctor from a 4.3L.
    Obviously I will need a custom timing cover, question is how the crank pos. sensor
    needs to be oriented. The inline crank is the same dia. as a small block/4.3L, not sure about the relation keyway to TDC #1.
    On the V-6/8 motors it seems the sensor is placed 45° off center or parallel to the cylinder bank. Would I need to place the sensor parallel to my cylinders as well?

    If I wanted to run a high resolution crank signal on an I-6 would that even be possible? 18x reluctor??

    Thanks,
    Lennart
    2005 RCSB 2500HD GMC Sierra DURAMAX LLY
    1955 Chevy Truck 1st series, being restored
    2002 Mercedes C270 CDI

  3. #13
    Senior Member
    Join Date
    Aug 2006
    Posts
    188

    Default

    Quote Originally Posted by Lennart View Post
    I am planning to convert an old inline-6 (292) Chevy to EFI. To keep the look as
    original as possible I prefer to keep the distributor. My plan is to install the 1x cam
    position sensor in the inline distributor and add a 3x crank reluctor from a 4.3L.
    Obviously I will need a custom timing cover, question is how the crank pos. sensor
    needs to be oriented. The inline crank is the same dia. as a small block/4.3L, not sure about the relation keyway to TDC #1.
    On the V-6/8 motors it seems the sensor is placed 45° off center or parallel to the cylinder bank. Would I need to place the sensor parallel to my cylinders as well?

    If I wanted to run a high resolution crank signal on an I-6 would that even be possible? 18x reluctor??

    Thanks,
    Lennart
    Hi Lennart,

    You might want to create a new thread as this thread is unrelated to what you're trying to accomplish.

    I don't have details available for sensor/reluctor orientation for your project, but I can tell you that GM never wrote a calibration for a high resolution crank reluctor with the V6. You will be stuck with a single coil and distributor using the 3x crank and 1x cam signal.

    Hope this helps,
    Mike
    24x LS1 PCM on Early Small-Block Chevy and LT1/LT4
    http://www.eficonnection.com

  4. #14
    Lifetime Member Aloicious's Avatar
    Join Date
    Nov 2007
    Posts
    453

    Default

    forgot about this thread. just a post install update for anyone interested, the CMP retard offset PID just logs a constant zero, Mike is correct, that as long as the cam is installed correctly, there is no offset to adjust.
    1996 c1500 gen1e 5.7L - the "LS31", 24x CNP, LS2 coils, modified T56, 12200411PCM running COS3, zz4 cam, custom MPFI, etc. coming soon: Twin Turbos

  5. #15
    New Member
    Join Date
    Sep 2017
    Posts
    5

    Default

    Quote Originally Posted by Aloicious View Post
    forgot about this thread. just a post install update for anyone interested, the CMP retard offset PID just logs a constant zero, Mike is correct, that as long as the cam is installed correctly, there is no offset to adjust.
    Not sure if you're still monitoring this Wildside, but I'm having some issues with my setup and have started to wonder if this is related to the placement of the vortec dizzy on my 0411PCM conversion of a SBC 24x.

    I'm getting horrible stuttering/backfiring and surging, more prominent (permanent) in low revs and extended cranking before it starts.
    You mentioned the alignment is not critical, but would this be a still be the case if the dizzy used for 1x cam signal was off by 180 degrees?
    Alternatively, if it is off by 5/10 degrees could it still cause this or it doesn't matter where it is, so long as it's present?

    One other quick question, does the vortec distributor have a different pinout config to the LSx cam signal sensors or are they same?
    I assume it's the same otherwise I wouldn't have a tacho reading, but I had a problem with the crank sensor when the vortec pinout was different to the LS1 pinout.

Page 2 of 2 FirstFirst 12

Similar Threads

  1. IBPW {B4005} {B3701} correlation
    By 5.7ute in forum General (Petrol, Gas, Ethanol)
    Replies: 22
    Last Post: August 12th, 2010, 09:19 AM
  2. crankshaft correlation
    By pullincrazy88 in forum Vortec V6/V8 Specific
    Replies: 1
    Last Post: May 16th, 2009, 02:04 AM
  3. MAP/TP Correlation
    By DrX in forum General (Petrol, Gas, Ethanol)
    Replies: 8
    Last Post: February 10th, 2009, 05:13 PM
  4. crank relearn on 97 L31 vortec truck?
    By sean3393 in forum General
    Replies: 0
    Last Post: July 31st, 2007, 05:29 PM
  5. Vortec Crank Relearn?
    By Lextech in forum Vortec V6/V8 Specific
    Replies: 3
    Last Post: April 17th, 2007, 01:35 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
  •