Problems with 1-4 cyl. Not working at all

Hello,
Have some problems with right bank cylinders (1-4). They just stopped working...
I've checked the ignition coils - doesn't have a spark there. Not sure if fuel injectors are opening too.
I thought that I have problems with blown ECU, but tried to change ir with the left cyl. bank ECU - nothing changed. Left side was working as before, right side still 'dead'. Disconnected the plug from ECU, tested if I have power supply. Yes it has. Although the right ECU had one more extra cable with power supply. Strange...
Some additional and interesting info: then I try to start an engine (turn key to the ignition pos.) on the dashbord I can watch only the 5-8 CEL ans 5-8 slow down lights turning on. It seems like that the right bank ECU is 100% dead, but it isn't...
And some more extra info: then I was going from my place to repair shop all 8 cyl. started to work for few minutes (turning the 5-8 CEL on for few seconds). Opened the engine lid, closed and again 4 cyl there gone...
I've tested in car allmost all sensors directly and it seems that all are working properly.
Without detailed repair manual (with wiring diagrams) I can't find what and there I can check. There can I find these manuals?

Now car works only on 4 cyl... Have some suggestions?


Sorry for my english... It's not my native language

 

Try swapping main relays

 

floor fuse and relay box?
Been there... done that...

 

348 or 355?
Sounds like a bad connection somewhere or a bad wire.

 

f355. 2,7 motronic.
I'm thinking about bad connection too, but there shood I start? I guess I should check underneath the floor fuse and relay box?
But it's a little bit strange that on the cable (to ECU) plug I have all the power supplying cables (even one more then at left side ECU's plug)... And still don't have working ECU...

Edit: HELP!!! I haven't done any km's/miles in 7 past days - I'll fall in depression if another 7 days will past the same...

I need to drive this car of perfection!
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Crank sensor???

 

Tested only the resistance; almost the same - the difference was only in few ohms. Tomorrow i'll check the whole signal with engine running.

 

It has been a long time for me with 348's. There is a screw in plug above left shock tower area just under that flat part where you would most likely park a tool when you are working on the car. Also check ground to the valve cover right under the fuel rail on effected side. 10mm hex nut about 1/4" black wire.

 

If there are 2 coil wires...probably a bad coil wire on right bank?

 

Swap coils side-to-side, see if it changes. Then do igniters the same. Igniters are sometimes a problem, and can be periodic as you described. Good-lookin' car!

 

been there, done that... nothing changes... Thanks for advice.

I'll check it as soon as possible. Thanks

 

From this description you could have a bad catalytic converter temperature ecu, or a bad thermocouple. Try disconnecting the catalytic converter ecu from the main wiring loom and see if the "dead" bank fires.

That's my guess.

 

I thought the OP had a 348. But looks like 355 2.7 motronic. If like the 348 then the exhaust ECU (aka slow down ECU) disconnect will not throw a CEL like on 2.7 348's. It is the 5.2 motronic (shared with the 550) that looks for the SDECU and will throw a code and MIL.

 

Problem solved. Bad connection in the fuse box. Soldered every connection in fuse box and checked all the wires.

Thanks for your advices!