bought a 2008 xsara picasso 1.6vtx 16v non starter cheap

[vincentfishing]

Have been out this morning to take readings at injector plugs with them connected and disconnected heres what i got.....

All plugs off injectors
ignition on position 2(precrank) 12.3v on all supply wires earthed to block
on cranking voltage fluctuates all over the place downwards,

with plugs back on
12v on feed and 12v on signal backprobe,
on cranking voltage fluctuating again,

with ignition off and injectors unplugged again,
resistance across the terminals of each individual plug o.oo ohms

with plugs off injectors
signal terminal of plug tested for voltage to earth
ignition pos 2 , 5.6v
cranking voltage fluctuates
key out car locked still 4.2volts

this 4.2volts at signal terminal of injector did not drop until some minutes later when relay clicked(bsm?) presumably as bsi had then cut all power?
unlocked car no voltage at signal(1.1mv) turned key to pos 2, bsm clicked and 4.2v at signal terminal of injector
cranked car and voltage fluctuates up to 5v+

presuming this 4.2v is problem that needs tracing??

[vincentfishing]

Just double checked signal voltages at disconnected injector plug behind inlet manifold, all 4.3 ish volts,
Checked for continuity and ohms from this plug back to ecu plug, all wires good.
Ground the ecu to chassis for the hell of it as i had read about this on other posts, voltages dropped from 4.3 to 3.5v ish .
Hoping someone will now conclusively say ecu is pooped as it appears so to me ! If so I can start looking for a matched set of bsi/ecu me745/keys , 2008 1.6 16v to swop over ???

[xantia_v6]

A question for the experts... Is this one of the vehicles that is prone to damage to the ECU grounding if the jumper cable is flashed to the ECU case when jump starting?

[wheeler]

A question for the experts... Is this one of the vehicles that is prone to damage to the ECU grounding if the jumper cable is flashed to the ECU case when jump starting?

What usually happens is the ECU casing gets shorted on the battery positive jump post when moving it out the way to do a clutch change without disconnecting the battery. This car had a recent clutch change but i asked the OP to check for arcing marks on the ECU casing as this is a dead giveaway that this has happened, it was inspected inside & out for this?

If you are getting a good regular pulse with the noid light at all the injectors on crank then im not sure if i would look too much into the 4-5v you are getting with the ignition off, may just be back voltage from somewhere inside it??

[vincentfishing]

What usually happens is the ECU casing gets shorted on the battery positive jump post when moving it out the way to do a clutch change without disconnecting the battery. This car had a recent clutch change but i asked the OP to check for arcing marks on the ECU casing as this is a dead giveaway that this has happened, it was inspected inside & out for this?

If you are getting a good regular pulse with the noid light at all the injectors on crank then im not sure if i would look too much into the 4-5v you are getting with the ignition off, may just be back voltage from somewhere inside it??

I only checked the outside of the casing and there wasnt a mark on it,
So maybe i should check inside too ??
And i am getting 4-5v with ignition ON pos 2 but as you say noid light flashing,
Going to take off inlet manifold tomorrow and change injector thats fueling into one of the non fueling positions just to rule out possibility of three duff injectors,
after that will pull apart ecu to have a look inside, believe i have to heat up outer edge of ecu to soften sealant to be able to prise casing off enough to cut sealent ??

[vincentfishing]

Just managed to get inlet manifold/ fuel rail out before it rained,
Reconnected fuel etc with it out of engine, used left off all injector plugs .
Plug the known good injector plug on to each injector and cranked ,
The good plug fired all injectors, so all injectors good.
Tried different plugs and no fuel spray..
So at least ruled out one thing ,
Still looking at dodgy ecu ??? I cant see anything else other than incorrect pulsing from ecu causing this problem ???

[civvie]

If you think the ecu is ruggered maybe get in touch with ap-reman, they can test it and advise, but no doubt charge for testing but at least it will give an indication on the next step.
Just a thought.

[vincentfishing]

If you think the ecu is ruggered maybe get in touch with ap-reman, they can test it and advise, but no doubt charge for testing but at least it will give an indication on the next step.
Just a thought.

Once i decide to move to next step will probably buy secondhand ecu/bsi/ keys, cheapest option i think.

[vincentfishing]

Took ecu apart , was cooked !!
On hunt for matched set of..... me745 ecu/bsi and keys .
Thanks wheeler for your input, got there in end,

[vincentfishing]

[imgimgimg]

[wheeler]

Oh dear, any signs of any arcing on the outside casing?
I thought when you originally said you inspected the ECU with a magnifying glass you meant the PCB??

[vincentfishing]

The outer casing on first appearance , to me ,seemed fine..
After i opened casing and saw damage inside i relooked at case, and there was a slight change of colour , slightly lighter grey, in area adjacent to inside damage,which was not what i was looking for on arcing damage, i am suprised at the lack of clearly visual damage outside the caseing compared to the carnage inside !
But this car was bought as a project/ learning exercise to learn more about electrickery on petrol engines, and Ive learnt a lot already and am enjoying the challenge !

[wheeler]

When the ecu is plugged in does the marks on the outer casing line up perfectly with the positive jump post nut by any chance if you stretch it over??

[vincentfishing]

Going out shortly to take out bsi , will check on ecu position whiĺe i am there

[vincentfishing]

The mark on the cover is near the post but there would be a gap between this cover and the bolted on support mount, there is no mark on the mounting bracket which would be the part that hits the positive post ? Maybe it earths through the mounting plate via the holding bolts and into the ecu and blows out wards , hence the burn marks inside the back ecu cover