Is it just coincidence?

[Island530i]

I tried a stomp test for the first time today, no fault codes. About 30 minutes later the car started to hesitate terribly when trying to accelerate as though it was running out of gas. After pulling over at a gas station I did a stomp test, now it is showing 1221 (O2 sensor1). I put some fuel in and drove back to work, now my check engine light is on continuolsy however it seemed to run okay for those 4 miles back. Is this something related to the first stomp test or is it just coincidence?

[dacoyote]

I tried a stomp test for the first time today, no fault codes. About 30 minutes later the car started to hesitate terribly when trying to accelerate as though it was running out of gas. After pulling over at a gas station I did a stomp test, now it is showing 1221 (O2 sensor1). I put some fuel in and drove back to work, now my check engine light is on continuolsy however it seemed to run okay for those 4 miles back. Is this something related to the first stomp test or is it just coincidence?

just coincidence....

reboot the car... shogun style....

[632 Regal]

http://www.bimmer.info/forum/showthread.php?t=16391

[DaCan23]

http://bagekko.home.comcast.net/dacans_pictures/homer_reboot.jpg

[Island530i]

Whats the easiest way to reboot? I've never had to do that before. Wow my old e30 was alot easier to figure out.

[dacoyote]

Whats the easiest way to reboot? I've never had to do that before. Wow my old e30 was alot easier to figure out.

search shogun reboot...

[Island530i]

Thanks, I'll try the reboot after work and let you know if anything changes. It figures everything is always fine until the day before a roadtrip.

[Island530i]

Did the reboot last night, seems to be fine now in fact the looping idle I was getting sick of is now gone as well. Thanks for all of the help.

[SRR2]

All you need to do is disconnect the battery for 5-10 minutes. That "shogun reboot" business is unnecessary. It's not going to hurt anything, but it's not going to accomplish anything that simply disconnecting the battery won't.

[Island530i]

Thats what I did, I disconnected the battery and let it sit unhooked while I had dinner. I did'nt feel the need to short the system out.

[dacoyote]

Did the reboot last night, seems to be fine now in fact the looping idle I was getting sick of is now gone as well. Thanks for all of the help.

Amazing what a reboot does...

[Gayle]

Thats what I did, I disconnected the battery and let it sit unhooked while I had dinner. I did'nt feel the need to short the system out.


Educate me guys. What does Shogun's procedure accomplish over and above disconnecting the battery as Island530i did?

[Alexlind123]

Educate me guys. What does Shogun's procedure accomplish over and above disconnecting the battery as Island530i did?

Absolutely nothing. I hate to discredit shogun, as he is one of the most helpful and interesting people on this board, but the computer reset is used on many cars apart from our beloved e34s and is certainly nothing new. Touching the terminals together wil dimply discharge the capacitors and and remove any residual voltage in the system more quickly than simply disconnecting the bettery for a period of time.

[SRR2]

Right. There are enough parasitic loads (like interior, hood, and trunk lights, the LKM) on the system to discharge any caps at the input of the elex within a few seconds. In fact, many loads are behind the load reduction relay which of course drops out the instant the battery is disconnected with the key on. However the only loads you really care about are the ones that are on battery keep-alive, and those will discharge in a matter of well under a minute. I've had occasion to reset ECU and other body elex quite a few times in a bunch of different cars. I've never seen one that requires more than a minute, and nothing other than disconnecting the battery has been required.

You can prove this for yourself. Connect a DVM anywhere that unswitched 12V is available. Disconnect the battery. Note how long the DVM stays above a volt. You will note that it falls nearly instantly (usually faster than the meter's sample period), which means that there's nothing in the system holding up any of the unswitched loads, therefore there's no benefit in connecting the battery terminals together.

I'd like to see all mention of this technique vanish permanently. I've seen it explained so poorly a couple of times -- here and elsewhere -- that some clueless newbie could conceivably interpret the instructions such as to connect the terminals together while the battery was still connected. Not a good idea at all.