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Thread: Engine Revs again after returning to an Idle.

  1. #1
    Potential Tuner
    Join Date
    Jun 2019
    Location
    Iowa
    Posts
    9

    Engine Revs again after returning to an Idle.

    I have a 2010 Escalade Engine with a Cam Swap. 235/247, .649"/.629", 113 LSA . The issue I'm having is if I rev the engine in neutral then let off the pedal it will return to idle but then rev again slightly even with out touching the pedal. It seems like its over compensating for the idle control. I notice on the log file its actually commanding the throttle to open slightly on the bounce. Can someone point me in the direction of what could cause this problem? Thanks

  2. #2
    Advanced Tuner
    Join Date
    Dec 2011
    Location
    Amarillo, TX
    Posts
    250
    is the RPM dropping below commanded idle before it revs back up? If so, probably needs some work to keep that from happening in the first place. The Rev is likely the computer trying to keep itself from stalling.

    If you posted a tune and log we might be able to help.
    JTC Performance - Authorized HP Tuners Reseller
    Performance Tuning in the Texas Panhandle

  3. #3
    Potential Tuner
    Join Date
    Jun 2019
    Location
    Iowa
    Posts
    9

    Thanks for the Reply and any advice you have for me

    Hey Thanks for the Reply. I ran it for a bit tonight and it could be my imagination but it seemed to be getting better. You'll see three revs at the end of the attached log and I got no bounce at all. I read on a message board somewhere that a dirty throttle body could be the culprit as well. This is a junk yard motor that sat for awhile before I got it so do you think that could cause this? I haven't drove the vehicle yet since I don't have all my alternator and fan wiring finalized yet. Just playing in my driveway a little bit.

    On a totally different topic.. it doesn't seem to have any power when you put a load on it. You can see the middle of the log I pulled it up to about 2300rpm holding the brakes and it just kinda stalls out. Even if you feather the pedal and give more gas it really doesn't give you anything. I'm wondering if the PCM is limiting power. I have run compression test on the engine and it checks out ok. It starts good, idles fine, and even revs in neutral well and the vehicle moves forward ok during normal driving. (again in my driveway about 100ft) Just no power when you mash it. My Wideband is showing it a little lean while my STFT + LTFT are showing it rich at -15 or so, trying to back out fuel... so I'm not sure what is going on there. I'm a newby to tunning a small block. I've worked in Engine Test at my job before but it was on Big Diesel engines. This is an LS swap into a 1984 S-10 with a power glide. I'm not running catalytic convertors

    The only codes it shows are:

    0x7E8: P0230 - Fuel Pump Primary Circuit (Pending, Old, History)
    0x7E8: P0463 - Fuel Level Sensor A Circuit High (Pending, Current, Old)
    0x7E8: P0481 - Fan 2 Control Circuit (SES, Pending, Current)
    0x7E8: P0622 - Generator Field Terminal Circuit (Current, Old)
    0x7E8: P0650 - Malfunction Indicator Light Control Circuit (Pending, History)

    The generator is not working yet (just got it wired in today) , the fuel pump is standalone and not run thru the PCM. No Fuel Gauge Hooked up yet, I have the fans run on Fan 1 output.

    Finally I'm really not comfortable with these engines getting so hot. 220 -240 in my driveway seems a bit ridiculous. I have the fans running on a Superior Radiator setup. I notice the MAP is all over the board sometimes even when its idling. I know its a big cam but it idles fairly well at about 900rpm so I would expect the MAP to be more consistent. Do you think I might have a manifold leak somewhere? Wouldn't that explain the overheating?

    Anyway Thanks in advance. I know I threw a lot of stuff out there and I have to deal with it one piece at a time. I am grateful for any advice you can give me to point me in the right direction.
    Attached Files Attached Files