Problem after disconnection batt

[bschucher]

Hiya.. yesterday i disconnected the neg cable for my batt to take apart the horn. I was unable to take the horn off but now the car wont run. It starts and idles but when i try to press the accelerator it just bogs down like its gas starved. Any ideas??

Edited April 18, 2006 by bschucher

[stumpjumper]

Hiya.. yesterday i disconnected the neg cable for my batt to take apart the horn. I was unable to take the horn off but now the car wont run. It starts and idles but when i try to press the accelerator it just bogs down like its gas starved. Any ideas??

what were you doing when you tried to get to the horn? were you going after the alarm horn or the steering wheel horn?

[bschucher]

Hiya.. yesterday i disconnected the neg cable for my batt to take apart the horn. I was unable to take the horn off but now the car wont run. It starts and idles but when i try to press the accelerator it just bogs down like its gas starved. Any ideas??

what were you doing when you tried to get to the horn? were you going after the alarm horn or the steering wheel horn?

Was the steering wheel horn.. See new post for update

[mikefocke]

The engine control computer lost all memory of what is normal and what it should do. It learns over the next 100 miles. So let it idle for a while, let it warm up, then see if it is at all driveable and drive it for a while. Things should improve. It'll be lumpy and crankey for a while, then slowly get better.

[bschucher]

The engine control computer lost all memory of what is normal and what it should do. It learns over the next 100 miles. So let it idle for a while, let it warm up, then see if it is at all driveable and drive it for a while. Things should improve. It'll be lumpy and crankey for a while, then slowly get better.

Now this is interesting.. Do these cars have a history of this type of behavior? What i learned today is that if i let it idle until its at normal operating temp... its fine. Should this happen any time you disconnect the battery? I would think not..

Edited April 22, 2006 by bschucher

[Rom]

Yes, it's true that after disconnecting the battery your ECU will lose all of its adaptive programming and reset back to defaults. However, it shouldn't be that bad. I've disconnected my battery many times (as I've done on many Motronic-based adaptive learning ECU's), and it's never that bad - I hardly notice it. After a few miles things are definitely better - but thats mainly because the ECU has adapted to my driving style. The adaptive learning lets the ECU optimize based on your style - and thats mainly for fuel-efficiency or performance (depending on how you drive).

The engine should never be seriously bogged down after an ECU reset. Give it a few miles though and see if the ECU learns to even things out. In your case the ECU might be reducing output (retarding timing, etc) to smooth things out for you, and the defaults are too advanced. In that case you might have other issues that are not apparent after the ECU learns to smooth things out. I'd get your ECU codes read at some point to see if there's any other issues.

What year is your car? When's the last time a service was done?

Thanks!

Shash

[bschucher]

Yes, it's true that after disconnecting the battery your ECU will lose all of its adaptive programming and reset back to defaults. However, it shouldn't be that bad. I've disconnected my battery many times (as I've done on many Motronic-based adaptive learning ECU's), and it's never that bad - I hardly notice it. After a few miles things are definitely better - but thats mainly because the ECU has adapted to my driving style. The adaptive learning lets the ECU optimize based on your style - and thats mainly for fuel-efficiency or performance (depending on how you drive).

The engine should never be seriously bogged down after an ECU reset. Give it a few miles though and see if the ECU learns to even things out. In your case the ECU might be reducing output (retarding timing, etc) to smooth things out for you, and the defaults are too advanced. In that case you might have other issues that are not apparent after the ECU learns to smooth things out. I'd get your ECU codes read at some point to see if there's any other issues.

What year is your car? When's the last time a service was done?

Thanks!

Shash

Its a MY 98. My wife bought it recently from a dealer that was not Porsche. It has had a CEL on for a lil while with a scan noting a downstream O2 Sensor. It has been running fine up until batt. disconnect. It just turned 30K miles and i i guess is due for that service now.