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Thread: 98 T/A with SS3 cam won't idle or fuel right

  1. #1
    Tuner in Training
    Join Date
    Aug 2020
    Posts
    22

    98 T/A with SS3 cam won't idle or fuel right

    Swapped and repinned for 411 PCM and can't get the car to run right since.
    Won't hold idle speed and runs out of fuel if I hold the RPM up around 2k. (lean on AFR and o2's)
    Not getting any codes. I haven't even turned off the rear o2's but not getting codes for it, the checks are 'incomplete' (cats and rear 02's are gone)
    I failed the MAF and no change, ran just MAF and no change. Dynamic is the same.

    I had this car tuned and running great befofe swapping to the 411. I swapped the injector tables, VE, MAF, timing and some others using compare.
    Not sure if something is wrong with the tune or what. NO vac or exhaust leaks. Changed nothing else besides the PCM and the repin mechanically.

    Verified all grounds and batt/ign + at the PCM and checked all the pins for any not seated or bent pins etc. All the sensors are working. Can someone look at the log and see what I'm missing? I've only tuned a few cars (my cars) and need a clue on this.

    i logged with wideband and have histograms that dont look right (see log file)

    Attaching the tune file and log file from this evening. I'm not sure if my local tuner will help me with this, he's a bare minimum type of person and I'd hate to tow the car there, pay him for a tune and not get it running right. I'm in Kansas City FYI

    I suppose I could have wiped a lobe on the cam but wouldn't that throw a misfire code? I get some change in idle as I pull each injector connector.

    Can I graph the IAC? Car will sputter around 500 RPM then catch and idle nice around the prescribed 1100 RPM, hit the throttle and it'll sputter down low again for a bit until idle catches again. Is that a bad IACV? Car used to idle perfect before the PCM swap. TIA TIA
    TApullfuel.hptTAMAPWORKS.hpl

  2. #2
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    Needs more base running airflow for sure and why is your idle timing so high around 30 degrees?

    Make sure fuel pressure is staying the same. Disable abuse mode, set it to 7,000+ rpm and 0mph.

    Turn off all the rear o2 sensor codes and anything else it isn't using anymore.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner in Training
    Join Date
    Aug 2020
    Posts
    22
    Hey yea I really appreciate you taking a look. Your info got me going to the right way. I've got the car idling much better and driving pretty good.