Very strange oversteer
03-30-2003, 08:53 AM
#32
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No Mas, (no pun intended there) it is not just your car. Lately I have been doing some timed acceleration runs from a 5mph rolling start. I'm trying to baseline my car before I do anything to it. Anyway, I agree. It is a very hard car to keep at a fixed rpm. It takes me a lot longer than I would have thought to get the car to a "steady" 5 MPH as the rpms will jump up or down a little more than expected in response to very subtle throttle inputs. Then, even with a steady throttle, I'll note some little surges. I just assumed the electronics were making some decisions on me. This is very minor and you would never notice it if your weren't trying to keep it at an exact, slow speed on a flat surface. Of course, it is hard to know if the surface you are on is truly flat, as my acceleration runs at various locations has proven.
03-30-2003, 01:00 PM
#33
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[QUOTE]Originally posted by Legal Bill
[B] ... in a light rain I redlined first gear and pulled a very quick shift to second on a section of road with a very mild right hand bend.
[B] ... in a light rain I redlined first gear and pulled a very quick shift to second on a section of road with a very mild right hand bend.
03-30-2003, 04:50 PM
#34
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Mas and Bill - it's more likely to be caused by engine temps. When the car is not at operating temps, the feature that cuts fuel to the injectors while coasting above 1000 rpm is disabled. Thus your deceleration will not be as quick as if there is no fuel being fed to the injectors.
It can also be due to your AC compressor kicking on and off.
Last thing is your ignition timing changes when the intake temps are higher...
It can also be due to your AC compressor kicking on and off.
Last thing is your ignition timing changes when the intake temps are higher...
03-30-2003, 07:09 PM
#35
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This happens on a completely warmed up car that has been running on 3 temperature bars for at least over 20 minutes. I do not understant the feature you're talking about that cuts fuel above 1000 RPM. Is that a typo? Did you mean 10,000 RPM? I'm not talking about such high RPMs and it's definitely not the rev-limiter. Also, the AC is not on.
The ignition timing change due to intake air temp rise is normal, isn't it? I mean,if it changes the ignition timing, it should stay that way while that high temperate is maintained and not fluctuate.
I have a feeling this is the environmental stuff - EVAP/EGR purge. Somehow honda's OBDII software has not been able to accomodate for this car's high revving engine - I don't have a helms otherwise I could try bypassing them and see if it makes a difference. I know that every model year of the G5 Prelude had a different (updated) emissions system, this shows they have been experimenting since OBDII was implemented in 1997 (or was it earlier?).
Anyway, what can you do but
?
[QUOTE]Originally posted by s2ktaxi
[B]Mas and Bill - it's more likely to be caused by engine temps.
The ignition timing change due to intake air temp rise is normal, isn't it? I mean,if it changes the ignition timing, it should stay that way while that high temperate is maintained and not fluctuate.
I have a feeling this is the environmental stuff - EVAP/EGR purge. Somehow honda's OBDII software has not been able to accomodate for this car's high revving engine - I don't have a helms otherwise I could try bypassing them and see if it makes a difference. I know that every model year of the G5 Prelude had a different (updated) emissions system, this shows they have been experimenting since OBDII was implemented in 1997 (or was it earlier?).
Anyway, what can you do but
?[QUOTE]Originally posted by s2ktaxi
[B]Mas and Bill - it's more likely to be caused by engine temps.
03-31-2003, 03:22 AM
#36
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Originally posted by mas
This happens on a completely warmed up car that has been running on 3 temperature bars for at least over 20 minutes. I do not understant the feature you're talking about that cuts fuel above 1000 RPM. Is that a typo? Did you mean 10,000 RPM? I'm not talking about such high RPMs and it's definitely not the rev-limiter. Also, the AC is not on.
This happens on a completely warmed up car that has been running on 3 temperature bars for at least over 20 minutes. I do not understant the feature you're talking about that cuts fuel above 1000 RPM. Is that a typo? Did you mean 10,000 RPM? I'm not talking about such high RPMs and it's definitely not the rev-limiter. Also, the AC is not on.
03-31-2003, 06:59 AM
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Originally posted by s2ktaxi
Most fuel injected engines today conserve fuel by cutting fuel to the injectors when you are coasting above 1000 rpm or so. But there are certain conditions when the ECU will raise that rpm threshold where fuel is cut off... If you are coincidentally around that threshold when you are beginning to get on the accelerator, it can cause the unsmoothness that you are referring to.
Most fuel injected engines today conserve fuel by cutting fuel to the injectors when you are coasting above 1000 rpm or so. But there are certain conditions when the ECU will raise that rpm threshold where fuel is cut off... If you are coincidentally around that threshold when you are beginning to get on the accelerator, it can cause the unsmoothness that you are referring to.
03-31-2003, 09:37 AM
#38
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Originally posted by Luis
... Do you have a death wish?
... Do you have a death wish?
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