Stop your Car Stalling from Clutch in!
Jul 31, 2016, 02:42 PM
#47
Good work MRFred! Thanks for the explanation of how that circuit/programming works. I wonder if that was one part of a few for my fueling issues, when car would display those symptoms randomly. Not sure though. I'll have to check when I get back up an running.
Aug 3, 2016, 09:59 AM
#52
Evolved Member
The exact same condition was experienced after long hard cruise or couple of 4th gear pulls . When you come to a stop the idle occasionally dips to 700 rpm .
Aug 4, 2016, 10:43 AM
#54
I've been assessing this issue for my Evo recently. My car doesn't stall, but in warmer weather, it dips down in the mid-600 rpm range when coming to a stop after a long decel. It does *not* look like its primarily an ISCV issue for my setup. The primary issue I'm seeing is lean fuelling when attempting to establish idle. The injectors shut off during decel, and then kick back on when nearing idle conditions, but since the intake manifold runners get cleared of all wall wetting during decel, fuel needs to build back up again before target AFRs will reestablish, at least that's my idea for the moment.
There is an "idle approach" enrichment, but it provides a very minor amount of enrichment, ~3-5% for the stock settings. Instead, it looks to me that Mitsubishi attempts to reestablish AFRs by kicking on the injectors earlier than needed for idle. For completely stock mapping, the injectors kick back on 200 rpm before reaching target idle. Like many people with big cams, I have raised my target idle to allow for smoother idle. However, changing the target idle does not simultaneously raise the rpm where the injectors kick back on. That needs to be handled by the decel fuel cut tables. The "start rpm" for the idle approach enrichment should also be raised by the same amount.
So far, I have only raised the decel fuel cut end engine speed by 100 rpm to match my 100 rpm idle speed increase (900 rpm target idle), and this has helped. Its not totally fixed though, and my next step is to raise the idle approach enrichment start engine speed by 100 rpm as well. If that doesn't fix it, then I'll experiment further, probably with the amount of idle approach enrichement, and then maybe with the ISCV demand as well.
For people with lightweight flywheels and/or high compression ratio, raising the ISCV Demand RPM adder values that the OP mentioned should help by allowing the engine to slow more gradually when pushing in the clutch. My clutch/flywheel combo is only 1-2 lbs lighter than the stock setup, so my setup shouldn't need much change. I wouldn't use exactly the values shown in the first post of this thread though. I would probably do something like:
500 0
1200 0 (changed from 1000 rpm to 1200 rpm)
1500 19.2 (stock = 0)
2000 19.2 (stock = 0)
2500 19.2 (stock val)
3000 28.6 (stock val)
3500 34.1 (stock val)
4000 42.4 (stock val)
4500 45.9 (stock val)
5000 45.9 (stock val)
An important difference is that I'm not including any adder in the idle range where the ISCV demand trims are active. Intead, I've set the 1500 rpm and 2000 rpm values to value to match the 2500 rpm value, and then changed 1000 rpm to 1200 rpm so that there is no adder in the idle range. I think this strategy should be helpful in combating fast rpm drop when pushing in the clutch.
There is an "idle approach" enrichment, but it provides a very minor amount of enrichment, ~3-5% for the stock settings. Instead, it looks to me that Mitsubishi attempts to reestablish AFRs by kicking on the injectors earlier than needed for idle. For completely stock mapping, the injectors kick back on 200 rpm before reaching target idle. Like many people with big cams, I have raised my target idle to allow for smoother idle. However, changing the target idle does not simultaneously raise the rpm where the injectors kick back on. That needs to be handled by the decel fuel cut tables. The "start rpm" for the idle approach enrichment should also be raised by the same amount.
So far, I have only raised the decel fuel cut end engine speed by 100 rpm to match my 100 rpm idle speed increase (900 rpm target idle), and this has helped. Its not totally fixed though, and my next step is to raise the idle approach enrichment start engine speed by 100 rpm as well. If that doesn't fix it, then I'll experiment further, probably with the amount of idle approach enrichement, and then maybe with the ISCV demand as well.
For people with lightweight flywheels and/or high compression ratio, raising the ISCV Demand RPM adder values that the OP mentioned should help by allowing the engine to slow more gradually when pushing in the clutch. My clutch/flywheel combo is only 1-2 lbs lighter than the stock setup, so my setup shouldn't need much change. I wouldn't use exactly the values shown in the first post of this thread though. I would probably do something like:
500 0
1200 0 (changed from 1000 rpm to 1200 rpm)
1500 19.2 (stock = 0)
2000 19.2 (stock = 0)
2500 19.2 (stock val)
3000 28.6 (stock val)
3500 34.1 (stock val)
4000 42.4 (stock val)
4500 45.9 (stock val)
5000 45.9 (stock val)
An important difference is that I'm not including any adder in the idle range where the ISCV demand trims are active. Intead, I've set the 1500 rpm and 2000 rpm values to value to match the 2500 rpm value, and then changed 1000 rpm to 1200 rpm so that there is no adder in the idle range. I think this strategy should be helpful in combating fast rpm drop when pushing in the clutch.
Aug 5, 2016, 04:15 PM
#56
i'm just not sure exactly what tables becuase some are RPM vs % where as others are engine temp vs %....so i'm just confused , im on the 96534706 rom....maybe like you said some dont have these tables? or values ? so i dont know where to try them
Aug 7, 2016, 04:44 PM
#57
i'm just not sure exactly what tables becuase some are RPM vs % where as others are engine temp vs %....so i'm just confused , im on the 96534706 rom....maybe like you said some dont have these tables? or values ? so i dont know where to try them
