Page 2 of 2 FirstFirst 12
Results 16 to 29 of 29

Thread: Weird $OD Spark Advanced FIXED, sorta

  1. #16
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by delcowizzid View Post
    Can you add a link to the files or add the xdf adx and the stock bin here that you are using
    http://www.gearhead-efi.com/Fuel-Inj...Information-0D

    dave w

  2. #17
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Quote Originally Posted by ony View Post
    sometimes i have to put a,b and so on in the file i started with my files get corrupted some times for no reason?
    I used my Ostrich 2.0 to verify buffer with chip to confirm the Memcal file vs. the file I downloaded from gearhead-efi.

  3. #18
    Fuel Injected!
    Join Date
    Jul 2013
    Location
    Newzealand
    Posts
    483
    Your guys xdfs are weird I wondered why the factory cal only had 15 degrees at 100kpa its setup to minus the bias off the main spark tables for some silly reason edited xdf and pow real spark figures 28 degrees up top at full throttle lol.have you ever confirmed actual advance matches commanded advance before this issue

  4. #19
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,847
    The bias is subtracted from the main spark tables. The values shown in main tables don't match actual spark advance unless the bias is taken out.

  5. #20
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    It's HAPPEN AGAIN!!

    I have another vehicle with a WEIRD Spark Advance!

    SA hotidle 12-08-18.jpg

    SA Combined 12-07-18.jpg

    Two completely different vehicles, one in Oregon the latest in California. One external engine difference is BOTH are using Holley TBI Throttle Bodies.

    Lighting CAN strike twice in the Same Place!

    dave w

  6. #21
    Fuel Injected! brian617's Avatar
    Join Date
    Apr 2013
    Location
    Arkansas
    Age
    45
    Posts
    711
    Dave, I've seen weird glitches like that with unrealistic numbers even with a Snap On scanner. I just chalked it up to intermittent communication issues with older obd1 vehicles. The question is are the symptoms related to the glitches in displayed spark advance? Cause and effect sort of speak.
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
    95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
    05 Outback XT 2.5L turbo gas auto

  7. #22
    Fuel Injected! S.O.B.B.'s Avatar
    Join Date
    Nov 2017
    Location
    Ontario Canada
    Posts
    167
    I also get weird spark numbers.I also thought it was just glitchy.it has not given any symptoms of any kind I'm identifying in logs.20181211_164956.jpg
    20181211_164936.jpg
    Jeeper
    87 sjimmy powered by a 92 cadillac 4.9L pfi on 7427pcm /700r4/ 8.8 3.55 rear/disc brakes.

  8. #23
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    The engine is running poorly, with or without TunerPro RT connected. I'm going to jump off the cliff and make the bold assumption, the spark is going negative without TunerPro RT connected.

    It's really weird, absolutely nothing in common between the two vehicles, expect both recently had installed Holley Throttle Bodies. Both vehicles ran great for a period of time after the Holley Throttle Bodies were installed, then not!

    Nothing in common means: different definition files, and different computer part numbers. The first vehicle had the problem using a bone stock chip. The second vehicle has a custom chip from me, using a G1 adapter.

    dave w

  9. #24
    Fuel Injected!
    Join Date
    Feb 2013
    Location
    Euless, TX
    Posts
    2,308
    Quote Originally Posted by dave w View Post
    The engine is running poorly, with or without TunerPro RT connected. I'm going to jump off the cliff and make the bold assumption, the spark is going negative without TunerPro RT connected.

    It's really weird, absolutely nothing in common between the two vehicles, expect both recently had installed Holley Throttle Bodies. Both vehicles ran great for a period of time after the Holley Throttle Bodies were installed, then not!

    Nothing in common means: different definition files, and different computer part numbers. The first vehicle had the problem using a bone stock chip. The second vehicle has a custom chip from me, using a G1 adapter.

    dave w
    My first question given my experience with Holley TBI units would be is the MAP sensor signal connected to the correct port on the throttle body. I have had better luck not using the one on the rear of the TBI unit. If you look at the way the throttle body is cast and the way the IAC ports are configured the port on the rear sits right in an area where the IAC gives it a false reading as it opens wider. The Holley units have a full manifold vacuum port on the front of them that gives more consistently reliable results. Cold startup and warmup will be exceptionally bad with the low vacuum reading delivered with the IAC opening. There was a good picture on here of the IAC port and how the rear vacuum port intersects it.

    Last edited by Fast355; 12-12-2018 at 02:32 AM.

  10. #25
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Moved MAP vacuum source to the front port, still has WEIRD problem.

    Fast355, thank you for the Holley information.

    Attached is the latest $OD data log.

    dave w
    Attached Files Attached Files

  11. #26
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,847
    I would want to verify the accuracy of the data. Is the ecm actually calculating weird spark values? Or is it random data?

    I might try to start by confirming the rpm signal is steady, then I might want to try using a scope on the REF and EST lines to see if timing is actually changing as much as indicated.

  12. #27
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    I agree a scope would be a diagnostic tool for a problem like this.

    I think the problem is real, the engine performance is severely degraded during the times the weird advance is happening.

    According to Google, I'm 550 miles away from the pickup. I'm thinking the chances of finding a scope cable that long would be challenging! Ok, a touch of humor, but it's still going to be challenging to find a shop that can scope the pickup.

    I'm thinking maybe disable all knock retard in the chip once again, which might "fix" the problem again? I understand that fixing the problem in the chip is not a "permanent fix"! If fixing the problem in the chip works, what is the actual fix?

    dave w

  13. #28
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,847
    According to Google, I'm 550 miles away from the pickup. I'm thinking the chances of finding a scope cable that long would be challenging! Ok, a touch of humor, but it's still going to be challenging to find a shop that can scope the pickup.
    We can order the cable inexpensively from Alibaba. But the shipping time from China is really poor this time of year.

    I'm wondering if the REF (input) signal is being affected which in turn is affecting both fuel and spark, or if the problem is only occurring in the EST (output) side.

    There are limits in the chip for minimum and maximum spark advance values. Those are generally applied after most of the spark advance calculations are made including knock sensor corrections. There are some occasions where a timing change is effected outside the limit checks, such as a timing change applied in $58 due to power steering activity. I believe it is a good idea to double check the min and max values and ensure they match the desired operating range. I also wonder if setting min and max timing to create a much smaller window wouldn't be a good diagnostic step. If the displayed timing varies dramatically even with a narrow window (say 10-20 degrees) you could look at code to see if there's an adjustment to timing outside the limits. You might also increase the temperature or rpm required to enable EST so the engine runs on module timing. If it will not run smoothly on module timing then you'll probably have little chance of making it run correctly with EST operating. There may also be a separate limit to how much knock correction is allowed. You could reduce the maximum allowable correction.

  14. #29
    Super Moderator dave w's Avatar
    Join Date
    Feb 2011
    Posts
    6,268
    Altitude Spark Bias = ZERO!

    I don't know why the weird spark advance is related to Altitude Spark Bias????????

    With Altitude Spark Bias set at the factory setting of 9.8 = weird spark advance!!!

    With All other Spark / Knock parameters set COMPLETELY STOCK except Altitude Spark Basis = Zero, then no weird spark advance.

    dave w

Similar Threads

  1. budget build questions for the advanced tuners 6825 ecm $0d bin
    By jim_in_dorris in forum GM EFI Systems
    Replies: 32
    Last Post: 05-15-2017, 07:54 AM
  2. YAY! Fixed a bricked pcm this morning...
    By babywag in forum OBDII Tuning
    Replies: 10
    Last Post: 01-12-2017, 06:07 PM
  3. An other weird question... LT1 ECU on a TPI???
    By X-cabsquarebody in forum GM EFI Systems
    Replies: 13
    Last Post: 11-08-2014, 06:19 AM
  4. Why is my timing way advanced sometimes?
    By Scrufdog in forum GM EFI Systems
    Replies: 9
    Last Post: 08-22-2014, 06:30 PM
  5. Twenty Thousand Degrees Advanced
    By ericburgundy in forum TunerPro Tuning Talk
    Replies: 16
    Last Post: 07-20-2014, 09:41 PM

Bookmarks

Posting Permissions

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