Results 1 to 5 of 5

Thread: 2000 GTP Mystery Timing

  1. #1
    Tuner CTX-SLPR's Avatar
    Join Date
    Jan 2008
    Location
    Livermore, CA
    Posts
    131

    2000 GTP Mystery Timing

    Howdy,

    Working on my 2000 GTP ECM'd engine swap and it's running like crap just off idle when I pull away from a stop sign. I know it's timing related and checking the log I'm not getting the commanded timing anywhere but it's really bad just off idle. I'm commanding 28-30deg (Engine is the older style 3.8L turbo motor, table is basically a stock 87 Grand National table) but only getting 15-17deg. I messed up something before so I'm more that willing to admit I screwed something up in the tables this time as well.

    The real data starts in the log ~5m in. I started logging while the car was warming up and found the WBO2 wire had pulled out of the MVPI block so had to go find the right screwdriver and get that fixed before I took it for a drive.

    Thanks
    Attached Files Attached Files
    Central TEXAS Sleeper
    Experimental Physicist

    Current:
    1964 Riviera (4.1L Buick Turbo6, 4L80E, L67 PCM)
    2012 Hyundai Genesis Sedan (3.8 GDI, 8spd Getrag)
    1998 Chevrolet Suburban K2500 (454, 4L80E)
    SOLD:
    1970 Riviera
    1965 Riviera GS (465 Super Wildcat, SP400) #'s Matching
    1967 Skylark Deluxe
    1997.5 Regal GS

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    9,039
    Perhaps related but your o2 sensor may be something to look into. You can see it not switching like normal and often just dies out on you.

    You have both a regular narrow band and wideband right?
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    Tuner CTX-SLPR's Avatar
    Join Date
    Jan 2008
    Location
    Livermore, CA
    Posts
    131
    Sorta both. It's one sensor (14point7.com Spartan Lambda 2) with a narrow band output into the computer and grounded through the instrument ground off of the NBO2 harness. I couldn't get it to work till I got that part sorted out. Since it's spliced into the harness it's pretty hard to put just a narrow band in place even if I wanted to. I didn't think much of it but I did notice it didn't look totally normal to me either.
    Central TEXAS Sleeper
    Experimental Physicist

    Current:
    1964 Riviera (4.1L Buick Turbo6, 4L80E, L67 PCM)
    2012 Hyundai Genesis Sedan (3.8 GDI, 8spd Getrag)
    1998 Chevrolet Suburban K2500 (454, 4L80E)
    SOLD:
    1970 Riviera
    1965 Riviera GS (465 Super Wildcat, SP400) #'s Matching
    1967 Skylark Deluxe
    1997.5 Regal GS

  4. #4
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    9,039
    I've seen weird things happen when people have tried to piggy back off the narrow band.

    Using both separate seems to always work better.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  5. #5
    Tuner CTX-SLPR's Avatar
    Join Date
    Jan 2008
    Location
    Livermore, CA
    Posts
    131
    Well besides the O2 doing funny things. Is there anything noticeable of why I'm getting such low timing numbers when I at least think I'm commanding higher timing that what I'm seeing. I really can't get anywhere on the tuning till I solve that issue.

    Thanks
    Central TEXAS Sleeper
    Experimental Physicist

    Current:
    1964 Riviera (4.1L Buick Turbo6, 4L80E, L67 PCM)
    2012 Hyundai Genesis Sedan (3.8 GDI, 8spd Getrag)
    1998 Chevrolet Suburban K2500 (454, 4L80E)
    SOLD:
    1970 Riviera
    1965 Riviera GS (465 Super Wildcat, SP400) #'s Matching
    1967 Skylark Deluxe
    1997.5 Regal GS