ok, I did some welding on the car the other night. I have heard bad stories about welding on computerized cars so I go one extra step. I disconnect the battery then I also unplug the computer just for safety sake. Did this back when I did the bodywork and no prob's. Also had the battery disconnected many times with no prob's. So when done, hooked the computer back up and then connected the battery.

Now it runs like crap.....bogs and chokes when hitting the gas in 1st (T5) and the idle keeps going up and down about 500rpm. It also threatens to stall after first starting it (the first idle dip)

MIL isn't on so there shouldn't be any codes. Any ideas? I am stumped here. Could this be something to do with the computer relearning? I have never ever had this problem before when disconnecting.

 

Yeah, the car's all messed up in the head. Yank the negative cable again. After you hook it back up, go for a drive, a half hour away at 50mph - and then a half hour back home at 50 mph. That should do it for ya, enough time to re-learn everything. Stumbling around town isn't gonna do it. This is how I reset/re-learn (or is that re-teach?) my ECM... and I do the same thing you do when I weld on the car- I pull the negative cable AND pull the ECM connectors out.

 

ok, thanks Tom, I'll give that a try. it is just weird that it has never happened before when disconnecting the battery or ECM. But Iguess there is a first time for everything, right.

 

If i weld my fender wells, should i do the same? And can i just dicconnect the batt and not the ECM? thanks

 

You can just disconnect the battery if you want (i am pretty sure the documentation I read only talked about that so you don't fry the ECM) but I like to play it safe and disconnect the ECM too. FOr the 30 seconds it takes it is good insurance. Stranger things have happened .

 

Well, took it for a boot on the highway today and it seems to be running MUCH better, so it appears that did the trick . Thanks TomP.

 

OOOps, I know about the battery thing but never remember. Or the EMC. I have seen guys unhook the batt but only when arc welding near the engine bay.

If the ground clamp is right near your work, the juice isnt flowing through but a few inches of metal. Right?

 

If you're equipment is setup properly and has a good ground, then it shouldn't matter. Why do you think that muffler shops never disconnect the battery? Because they know what they are doing and get a good ground to begin with.