Revs up quick, revs down slow (cruise effect?)
#1
Revs up quick, revs down slow (cruise effect?)
I always knew the PCM makes the stock engine "rev down" slowly for some reason (emissions?) but now that I put the cam in, it is much worse; almost a cruise-contol effect. I haven't done any PCM tuning yet so it's not caused by editing. Anyone know how to fix this with LS1edit?
#2
Re: Revs up quick, revs down slow (cruise effect?)
I always knew the PCM makes the stock engine "rev down" slowly for some reason (emissions?) but now that I put the cam in, it is much worse; almost a cruise-contol effect. I've haven't done any PCM tuning yet so it's not caused by editing. Anyone know how to fix this with LS1edit?
#4
Re: Revs up quick, revs down slow (cruise effect?)
OK thanks pekkaz, but I assume you mean "Airflow Decay in Gear" since P/N stands for Park/Neutral. Since I have a M6, I assume I would just adjust the values for all of the gears since the PCM has no way of knowing which gear I'm in.
#5
Re: Revs up quick, revs down slow (cruise effect?)
Ok, I was confused by the 'rev down'. Another thing to look at is if you have too much on the in gear row in the "Idle Air". Dunno how 'Airflow Decay in Gear' works with M6.
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#8
Re: Revs up quick, revs down slow (cruise effect?)
Noticed something interesting about this problem: if I push in the clutch, the rpm comes right down like it should; but if I pop it out of gear without using the clutch, the rpm floats down very slow! It's gotta be the PCM causing this . . .
#9
Re: Revs up quick, revs down slow (cruise effect?)
OK got the problem fixed . . . I verified the PCM was causing it by unplugging the IAC, and sure enough it worked great. So I plugged it back in and edited the P/N Airflow Decay and the Airflow Decay in Gear to the max values allowed by LS1edit. Problem fixed! Now I can take my foot off the gas and actually slow down! Thanks to everybody for your help.
#11
Re: Revs up quick, revs down slow (cruise effect?)
I should say the maximum integer value, 31.0, it will accept up to 31.99. I just kept putting in larger values until LS1edit would not accept them; you get the error message "This value is out of the byte range" if you put in too big of a number. I also got pretty good results by just using the largest value that was already in the table: 1.0.
#13
Re: Revs up quick, revs down slow (cruise effect?)
blinksz06, I found out last night the changes I had made to the decay tables hadn't taken full effect because I hadn't done a PCM relearn procedure. Once I unhooked the battery for a while, problem was totally solved! No more delay before the decay starts.