Rev Hang Issue?
06-10-2012, 10:03 PM
#1
Registered User
Thread Starter
Rev Hang Issue?
Just the other day, I started noticing that at cruising speed, when I let off the gas, the revs like to stay where they are, and don't drop AT ALL, or very little if they do. It doesn't matter if I'm at 7k, or at 3k, when I let off and push in the clutch, or throw it in neutral, the revs stay where they are 90% of the time. I've noticed that they drop like normal after a second of applying the brakes, or if I give the gas a good blip, they fall normally after that.
It's an '07 with the DBW throttle. There was no related work done to the car before this started happening. The only thing I did before I started noticing this was put new rims and tires on, and raise the back coilovers a little.
What could be causing this? I'm almost afraid to drive it anymore.
It's an '07 with the DBW throttle. There was no related work done to the car before this started happening. The only thing I did before I started noticing this was put new rims and tires on, and raise the back coilovers a little.
What could be causing this? I'm almost afraid to drive it anymore.
06-11-2012, 06:51 AM
#2
Registered User
Join Date: Aug 2009
Posts: 26
Likes: 0
Received 0 Likes
on
0 Posts
Your problem is most likely caused by the new rims/tires that you have. It is related to the VSA (vehicle stability assist) and its perceived differences in wheel speed after deviating from stock sizes. Here is another link related to your issue. I'm no expert on this, I just remember seeing threads on it in the past.
https://www.s2ki.com/s2000/topic/745...r-wrong-tires/
https://www.s2ki.com/s2000/topic/745...r-wrong-tires/
06-11-2012, 09:16 AM
#3
Registered User
Thread Starter
This is normal if you do what's highlighted in red. Many modern day cars will do this if you throw it in neutral (be it an automatic or standard) or just push in the clutch at speed and let go of the throttle. The ECU sees roadspeed but when you suddenly let go of the throttle and disconnect the engine from the rest of the drivetrain (no load) while sensing zero throttle position, it gets confused and can't figure out what the hell you're trying to do, so it hangs the rpm up for a short time. Even with a non-DBW S2000, it will do this but to a lesser extent. The ECU is wondering why you're doing such a stupid thing and tries to out think you. If you don't want it to hang the revs, then don't disconnect the engine from the drive wheels at speed just to see what it'll do. It's not a normal way to drive and it only serves to confuse the car's brains.
06-11-2012, 11:22 AM
#5
Originally Posted by xviper' timestamp='1339433949' post='21772413
This is normal if you do what's highlighted in red. Many modern day cars will do this if you throw it in neutral (be it an automatic or standard) or just push in the clutch at speed and let go of the throttle. The ECU sees roadspeed but when you suddenly let go of the throttle and disconnect the engine from the rest of the drivetrain (no load) while sensing zero throttle position, it gets confused and can't figure out what the hell you're trying to do, so it hangs the rpm up for a short time. Even with a non-DBW S2000, it will do this but to a lesser extent. The ECU is wondering why you're doing such a stupid thing and tries to out think you. If you don't want it to hang the revs, then don't disconnect the engine from the drive wheels at speed just to see what it'll do. It's not a normal way to drive and it only serves to confuse the car's brains.
And he is right... holding it in neutral while rolling around is retarded in any car. And the ECU *will* screw up.
06-11-2012, 12:04 PM
#6
Registered User
Thread Starter
No insult intended. All I'm saying is that I know my car, and I know it's behavior in certain situations, and it never did what he said. Even when not in neutral, when I would let off the gas, it would maintain speed indefinitely. I know what my car used to do, and I know what my car is doing now, and I can tell you it's not normal.
Thread
Thread Starter
Forum
Replies
Last Post