Citroen C3 charging / alternator problem.

[miki18]

Hi everyone.

I got a car that has milion fauls - So text is also a mile long. Please bear with me ....

It is Citroen C3 pluriel 1.4i petrol engine KFV (TU3A) ECU Valeo J34P

Car died totlaly (not even cranking). I diagnosed failed ecu. After getting used ecu (same software) from ebay I swapped eeprom and car started.
I took it to test drive it worked ok, but lights were blinking (dash and headlights). Voltage on battery was fluctuating from 12 to 14,5V.
There were dtcs for alternanator P0620 and orher two for internal ecu problem P1631 and P2101 for throttle body. I fixed last two with gas pedal repair... Alternator dtc remained.
After few starts of the car the second ecu died again !!! Same fault not even cranking ... My firtst thought was a gallon of petrol and a match
After cooling off (me.. not the car) I diagnosed ecu again and I got in but - "unknown computer" nad every parameter was showing : ???? ??
I wrote eeprom again and nothing... Then I got some MCU software from forum (not exactly the same sw number but for same engine) I wrote it in ecu and
CAR STARTED !! After that I reflashed first ECU and it also worked.
Now I was back to fluctuating voltage and alternator dtc. After checking all wires that I could think off (including mase) and battery replacement I bought new alternator. After replacement same problem
Then I found some unusual voltage spikes with oscilloscope (over 30v for a millisecond or two). Something was injecting spikes in to 12V. Changed ignition coil and the same...
After sparkplug replacement spikes disapeared . DTC for alternator also cleared. F...ing unbelievable but true. Looks like those spikes killed my two ecus.
Fluctuatung voltage is still present but not not always. When I start cold car there is usualy nothing wrong, after few minutes it stars fluctuating a lot, after few minutes more all better again . Sometines it is worse sometimes not noticeable.... It is the same with both ecus.

Is my new alternator failed again or maybe both ecus. Possible wrong software....

If someone has any idea please help !

Thanks

[miki18]

Anyone ....
At least any suggestion??

[darrenhyland]

Coil pack leaking high voltage across to 12v system?

[miki18]

I tried 3 different coilpacks.... same result :-(

[Meat-Head]

Awesome post.

ok,

1) remove alternator belt to eliminate alternator- inspect belt in your hand

2) start engine let idle, turns lights, heater ALL ON, let battery get to 12.0
Volts, then hold revs at 2500 for 2 minutes stop engine go round with
Somebody’s elses finger, battery terminals, alternator pulley
Anything that burns somebody elses finger, look at it (not exhaust manifold!)

[miki18]

If I remove belt or disconnect wire from alternator than there is no fluctuation....
Nothing is hot (except exhaust ) no bad connection...

[Meat-Head]

Thinking about it, Try cutting the small wire at altnator. Feed through a 2.2w bulb. To b+ see what happens

if you need to use dk thanks, to extend the wire, Soak in water first

[autobedrijfmaat]

Problem with the BSI maybe?

Grtz, Kevin

[ricketts0121]

It sounds like bsi problem to me