SAUJP Engine reving up and down on decel
#1
SAUJP Engine reving up and down on decel
Took a long cruise the other day and noticed that my rpms will go up and down from 1600- 1200 when decelerating from speeds above 70 mph in 4th gear locked, if im decelerating from 60 mph its noticeable. So I took a log today and noticed the spark advanced is jumping with the rpm change any ideas what could be causing this? Im using 8D with a slightly modified AUJP bin
Last edited by STEALTHWRAITH; 08-26-2024 at 06:56 PM.
#3
Re: Engine reving up and down on decel when going above 70mph
Took a look at the data...
I think the only thing in $8D AUJP that has spark related to vehicle speed is Highway Mode spark.
In your data, it seems like every time your spark timing starts "acting up" is when the ECM is in Highway Mode.
I'd check your settings for the Highway Mode spark.
I think the only thing in $8D AUJP that has spark related to vehicle speed is Highway Mode spark.
In your data, it seems like every time your spark timing starts "acting up" is when the ECM is in Highway Mode.
I'd check your settings for the Highway Mode spark.
#4
Re: Engine reving up and down on decel when going above 70mph
Yes I was recently playing with the Highway mode enabling it, just looked at the bin and I have no spark advance with highway mode the enable temp is 304, I do have perform Highway mode checked off on the flag though gonna uncheck that and try again. Before the long trip the car did die while driving pulled over and noticed the ignition coil plug got disconnected. What I'm seeing in the log is that it turns off the advance completely 10.2 is what I have the base set at in the tune and it fluctuates from 10-30s while the rpm's jump
#5
Re: Engine reving up and down on decel when going above 70mph
Yeah...It's almost like the EST connector is being intermittently disconnected, but I'm not seeing any code 42's being set.
Something going on with your ignition control module?
Something going on with your ignition control module?
#6
Re: Engine reving up and down on decel when going above 70mph
I'm going to test drive now went over the wiring to the coil will pull the G1 adapter and try straight aujp prom as well to see if its anything I did accidentally in the tune, I do have other ICM's that's in order for another day
#7
Re: Engine reving up and down on decel when going above 70mph
Ok seems to be something in the tune with the factory PROM SA fluctuates from 22-27 on decel at the same mph soon as I stick the G1 with custom tune it drops to 10.2 which is the base. Even with the stock PROM though I do noticed the RPM bounce up and down as it goes from 27 to 22 from 70-60mph below 60mph SA stays steady on both chips
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#8
Re: Engine reving up and down on decel when going above 70mph
Seem to be getting somewhere I have been using v7 SAUJP and just tried it without doing to many changes to the original supplied SAUJP bin, noticed that they prioritize lock up decel at 70mph they have the convertor locked up and SA at base timing the whole time no fluctuating up and down when "tcc-bypass coastin unlock if not in dfco" and "unlock tcc in dfco" arent touched. I need to go back and read the notes from prior versions to see when they changed this and how to get the SA similar to stock where it doesn't take out all the advance when in 4th unlocked as my SA is good when deceling in 3rd or in 4th locked I dont believe I have a mechanical spark issue
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