m20 ecu reset?

[moots]

Greetings,
Whenever i disconnect the battery (for 1 reason or the other) and reconnect,the idle becomes crappy and at times the engine dies off because of the low idle speed and the engine hesitates and falters at times when starting off from standstill.At cruise no problems.It takes 2 days for it to becum normal.Anybody experienced this b4?I suspect the ECU internal battery is de kaputten and cannot remember previous settings such that the ecu is 're-learning' the map.

I don't have this issue with my '86 e30 though.

I didn't have this problems during my early ownership of the car.(had car since '99),just maybe the last 2 years I noticed this happening.

Anybody with any explanation..........and a cure maybe? :D

[shogun]

A lot of people which have problems with their engine and also the auto trans do the reset procedure.
On the M30 engine with an OBDI it works as well as on other cars with ECU's.

After you have done the reset procedure, the basic program is still in the ECU and the ECU has to learn your driving style and adds those settings.
It is just like clearing your PC of all the crap and faults.
In case you drive an V12, you have do do an additional synchronisation of the throttle valves.
Detailed info about a reset is shown on my page below.

Usually after resetting you should drive the car at various speeds and RPM's and that it should work properly or better again.
That resetting process is a very nice thing.

[ukm5]

Greetings,
Whenever i disconnect the battery (for 1 reason or the other) and reconnect,the idle becomes crappy and at times the engine dies off because of the low idle speed and the engine hesitates and falters at times when starting off from standstill.At cruise no problems.It takes 2 days for it to becum normal.Anybody experienced this b4?I suspect the ECU internal battery is de kaputten and cannot remember previous settings such that the ecu is 're-learning' the map.

I don't have this issue with my '86 e30 though.

I didn't have this problems during my early ownership of the car.(had car since '99),just maybe the last 2 years I noticed this happening.

Anybody with any explanation..........and a cure maybe? :D

as stated its normal reset procedure - however it shouldnt run badly for 2 days...i accellerate hard in 1st or 2nd hold it for about 5 secs and it hiccups and thereafter it runs perfect. also the battery should be dissconnected for at least an hour before it forgets what its doing..

[shogun]

The battery disconnecting time you can reduce much, if you 'shorten' the plus-minus battery cables (after disconnecting from the battery of course) and switch ignition to position 2 then, or set the hazzard alarm on then. That draws the rest of the power out much faster from the system.

But to be sure, as you said one one hour is a good idea. Some people really do it for a too short time.

[winfred]

a few seconds is all it takes (i can verify the reset with my scanner) it should not run real bad after a reset unless you have considerable mods to the motor that the computer has to adjust for, or theres a small problem somewear, out of range sensor, air leak, miss adjusted/dirty throttle plate or some other little gremlin