code 1211 and 4121

Hi all 348 brothers,

I have a 94 348 spider which came out of the US, unfortunately the battery was completely dead when it came in Europe. So I fitted a new battery and started it. After driving for an hour it gave a CEL and ran rough. What i did next was disconnect the battery again and waited, the connected it again an try to let it idle for 10 minutes.. During idling the left (5-8) exhaust gasses felt warmer then the right ones (1-4). You can really notice that. The I read the codes and it said both banks have code 4121. After that I let it idle again and it threw a 1211 code on bank 1-4. So I shutted down. I felt the O2 sensors, sensor 5-8 is warm ,but 1-4 is stone cold.

What can cause 4121 and 1211?

Thanks

 

O.k. I found why the 4121 codes are there; the pulgs were disconnected by the previous owner. So next I installed again and swapped MAF from left to right and vice versa. Tried to started, no succes, it cranks but won't start. Even somethings back-fires. I smell fuel out of the exhaust, it probably doesn't sync? how can I test that?

 

during cranking it sometimes fires at a wrong order or not at all. it sometimes does run (barely then stops after 3 seconds or so).

 

Sounds like in your original setup you lost the right bank of cylinders.

When you switched MAFs it wouldn't run at all. Looks like you might have found the problem.

Check everything for good connections and evidence of rodent chewing etc.

 

swapped amf back and engine does start but barely idles. If you push the pedal it dies

It all happend after changing the battery.. strange strange strange. double, triple checked the battery but all is good.

Also when I crank I hear sometimes a "oempf" like it fire when it is not needed..

 

Does someone have any thoughs?

 

It sounds like one of the MAFs is dead and you might have fouled spark plugs.