Help shop needs help 328is -check engine light

[tonyvt328is]

So this shop replaced my driveshaft assembly-ok. Broke exhaust bolts ect,,-ok fixed. Used torch on manifold and welded mid section pipes back on.

Now check engine light on. Says all 4 02 sensors bad? Now way.

What could this be? Please help!!!!

Thanks
tony

[Spasso]

I'm wondering if the O2 sensors were contaminated by the vapor by-product of the welding, (inside the pipes).

[tonyvt328is]

Could they be cleaned??

Anyone know anything about this???

PLEASE HELP!!!!

[winfred]

take it for a good rip down the road then reset the light and see if it comes back after another rip, the back sensors hardly ever die and the fronts are not going to go at once, the 96 and up cars have problems with the crankcase vapor recovery system where it leaks vacuum and screws up the mixture which usually sets front 02 codes
they may of started it with the exhaust off the car and that set the codes

[tonyvt328is]

take it for a good rip down the road then reset the light and see if it comes back after another rip, the back sensors hardly ever die and the fronts are not going to go at once, the 96 and up cars have problems with the crankcase vapor recovery system where it leaks vacuum and screws up the mixture which usually sets front 02 codes
they may of started it with the exhaust off the car and that set the codes


Thanks I will try that.

Do you think putting a torch on the manifolds could have cooked one or both of the front ones? If one shorted would they all show bad?

Thanks for taking the time to reply!

Tony

[winfred]

unless they directed the flame right on the sensor and left it there (i test sensors with a propane torch and clean them with a mapp torch) it should be fine, it can deal with heat after all it doesn't start working till the tip reaches 600 degrees, i've yet to see one trigger codes for all my best guess is they started with them all unplugged

[tonyvt328is]

unless they directed the flame right on the sensor and left it there (i test sensors with a propane torch and clean them with a mapp torch) it should be fine, it can deal with heat after all it doesn't start working till the tip reaches 600 degrees, i've yet to see one trigger codes for all my best guess is they started with them all unplugged
----------------------------------------------------

THEY CANT CLEAR THE CODES. ANYONE HAVE ANY IDEA???

IM LOOSING MY MIND;)

[winfred]

at this point it's down to diagnostic skills, if they all crapped at the same time look for whats common for all of the sensors like the 02 sensor heater relay or if theres a fuse for the heater circuit

[tonyvt328is]

at this point it's down to diagnostic skills, if they all crapped at the same time look for whats common for all of the sensors like the 02 sensor heater relay or if theres a fuse for the heater circuit


It goes back in today for a new check. the shop has purchaced the BMW chip for their scan tool..

BTW..Just found out my 328is has M3 exhast....

Runs ok with check engine light on but bad gas mileage...

[tonyvt328is]

It goes back in today for a new check. the shop has purchaced the BMW chip for their scan tool..

BTW..Just found out my 328is has M3 exhast....

Runs ok with check engine light on but bad gas mileage...

They cant fix it. Installed 1 new 02 sensor still shows both front bad. They told me they dont know what to do. I hate to go to the dealer.

Any ideas??? Anyone?

Thanks

[tonyvt328is]

unless they directed the flame right on the sensor and left it there (i test sensors with a propane torch and clean them with a mapp torch) it should be fine, it can deal with heat after all it doesn't start working till the tip reaches 600 degrees, i've yet to see one trigger codes for all my best guess is they started with them all unplugged


So if they dont come on till 600 why does the light come on imediately. Seems like the car would have to warm up before the circuit would check the gases?

[winfred]

that's why it's probably not the sensors, if you replaced one front sensor id replace the other so you are not fighting the new sensor out reading the old one and get the codes reset, see what happens and how fast, immediately id be checking the wiring, shortly id be looking for vacuum leaks (usually it's the oil vapor separator under the intake


So if they dont come on till 600 why does the light come on imediately. Seems like the car would have to warm up before the circuit would check the gases?

[tonyvt328is]

that's why it's probably not the sensors, if you replaced one front sensor id replace the other so you are not fighting the new sensor out reading the old one and get the codes reset, see what happens and how fast, immediately id be checking the wiring, shortly id be looking for vacuum leaks (usually it's the oil vapor separator under the intake

Thanks Im going to go over it myself first. Can I check basic voltages and/or resistances with a VOM? Im an electronics tech so I know how to look at such things.

Know anything about Carsoft? How good it is? Cost?

Thanks for your input!
Tony

[winfred]

it's going to have a 12 volt feed going to the heaters in the sensors, the sensors make about 1v dc when they are hit with a propane torch and up to temp (usually about 30 seconds or so), if you have a graphing meter you can look at the responce time which is the most importaint part, at operating temp it should react quick to flame on and off of the tip, nearly straight up and down on the graph or about 1/10 of a second to fall to nearly zero