Hesitation when flooring it
Discussion
Dunno. The ECU will have reset and lost its adaptive setting which might affect it's behaviour. It's also possible that while you were grubbing around in the footwell changing the battery you disturbed the ECU wiring loom and it has developed a fault? If you disconnect the throttle pot this will cause a massive flat spot when you open the throttle, so you might try doing that and see if it gets dramatically worse. If not I'd take that as a sign that the ECU isn't talking to the throttle pot any more.
Guillotine said:
yep, sorry, we call them cpu's in my line of work.
the big black box in the footwell. ecu/cpu = engine brain
andy
Is it easy to disconnect or will I end up cocking the whole electric system up by pulling the wrong wires out?
Or indeed, do I need to touch it or just go for the 30 minute stop/start jaunt?
There are some specific conditions that have to be met in order for the adaptive settings to be updated. Mark Adams did explain in some detail but I'm afraid I've forgotten a lot of the details. From what I can remember it requires the coolant temp to be in the operating range, and the engine ticking over at a particular speed with constant throttle. Sorry I can't be more specific, but the main point is that just general driving around won't do it. The main thing you're achieving by resetting the ECU is clearing all the fault codes and putting the ECU back into normal operation. If the ECU has gone off in a huff because it has detected a fault then this can sometimes clear things up, at least until it detects the fault again.
GreenV8S said:
There are some specific conditions that have to be met in order for the adaptive settings to be updated. Mark Adams did explain in some detail but I'm afraid I've forgotten a lot of the details. From what I can remember it requires the coolant temp to be in the operating range, and the engine ticking over at a particular speed with constant throttle. Sorry I can't be more specific, but the main point is that just general driving around won't do it. The main thing you're achieving by resetting the ECU is clearing all the fault codes and putting the ECU back into normal operation. If the ECU has gone off in a huff because it has detected a fault then this can sometimes clear things up, at least until it detects the fault again.
It all seems a bit long winded just because I've changed a battery.
I'm obviously prepared to do what ever it takes to get it right but surely this procedure shouldn't be necessary every time somebody changes a battery? Or is it?
I've had to do this several times after working on the car.
when the battery is disconnected, it looses its settings and goes to a base map.
it then learns optimum (
) settings as the car is driven.
15-30mins will do fine.
yes, it has to come to temp, yeas it needs the range of throttle positions, yes it needs stop start etc etc, but it will learn 90% of your engines settings in 15mins!
andy
when the battery is disconnected, it looses its settings and goes to a base map.
it then learns optimum (
) settings as the car is driven. 15-30mins will do fine.
yes, it has to come to temp, yeas it needs the range of throttle positions, yes it needs stop start etc etc, but it will learn 90% of your engines settings in 15mins!
andy
Guillotine said:
I've had to do this several times after working on the car.
when the battery is disconnected, it looses its settings and goes to a base map.
it then learns optimum (
15-30mins will do fine.
yes, it has to come to temp, yeas it needs the range of throttle positions, yes it needs stop start etc etc, but it will learn 90% of your engines settings in 15mins!
andy
Excellent.
Andy, will I still need to unplug (reset) ECU or will the disconnecting of the battery have had the same effect anyway?
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