L322 pulling my hair out! (Not much left)

[backinblack]

Did the diags give the fuel pressures low/high?
HP regulator is a know common issue, ask me how I know.

EDIT: I don't remember seeing any fault codes.

 

[Crankington]

If its cranking over, there's only a couple of things it can be.

It's briefly firing on cold start being sprayed it, means no fuel.

Immobiliser has been bypassed and it's cranking so not likely ews at this point.

This pretty much leaves fuel pressure sensor on the fuel filter, should kick up a code but live data will show if this is working.
Camshaft sensor, will kick up a code.
Crankshaft sensor, won't kick up a code.
Injector leak off would have to be very bad not to start, should still start but be very rough.
Theres also a pressure sensor on the fuel pump/rail somewhere but that should give a code.

Thanks for this, yeah, so the fuel pressure sensor on the fuel rail was giving a code along with the immobiliser, so I think that’s my next step, get one ordered. I’ve tested the filter and all good.

 

[Crankington]

Did the diags give the fuel pressures low/high?
HP regulator is a know common issue, ask me how I know.

EDIT: I don't remember seeing any fault codes.

i need to triple check with the mechanic, but he said that the fuel pressure sensor was throwing up a code (this was all in French and I’m still learning so didn’t get all the info)

 

[Crankington]

do you have any specifics? actual DTC codes?

Yes so the ECU code was : P1602… have messaged the mechanic regarding the fuel pressure code.

 

[backinblack]

If the HP regulator has gone faulty it will cause low pressure so may show as a sensor fault.

 

[Crankington]

If the HP regulator has gone faulty it will cause low pressure so may show as a sensor fault.

This part right? https://ebay.us/m/XQ5e8w

 

[kermit_rr]

Yes so the ECU code was : P1602… have messaged the mechanic regarding the fuel pressure code.

this can be a canbus issue

 

[Crankington]

this can be a canbus issue

What does that mean? Nightmare?

 

[kermit_rr]

What does that mean? Nightmare?

could be a damaged/corroded connection or wire

 

[Crankington]

could be a damaged/corroded connection or wire

That sounds like a huge nightmare, there is so many wires in this car

 

[kermit_rr]

Only one is relevant! Check the ECU connectors for corrosion (,i expect you already have though,)

 

[Crankington]

Only one is relevant! Check the ECU connectors for corrosion (,i expect you already have though,)

Yeah have been through all the plugs on the ECU and tested for ground, live etc etc … for example, I was able to confirm that I am getting pulses of electricity to the injectors

 

[kermit_rr]

right, it cranks, the injectors energise, but it wont start.. you know there is a fuel (pressure?) related issue and you sent the ecu away to be meddled with...

 

[Crankington]

right, it cranks, the injectors energise, but it wont start.. you know there is a fuel (pressure?) related issue and you sent the ecu away to be meddled with...

Well I was told by another mechanic and the previous owner that the likely cause was the immobiliser…. Then another mechanic, came and did a diagnostic and told me to deactivate the immobiliser, and if that doesn’t work then replace the regulator… … seems I shouldn’t have listened to him, but doing my best

 

[pwood999]

They probably make more money doing immobiliser stuff than fuel regulators & pumps !!

Fuel pressure codes are just a clue something is wrong. The diagnostic should also show the actual pressure values.

 

[Crankington]

They probably make more money doing immobiliser stuff than fuel regulators & pumps !!

Fuel pressure codes are just a clue something is wrong. The diagnostic should also show the actual pressure values.

Well I’ve found a used but working replacement sensor on eBay for 30 quid , might be worth a punt?

 

[kermit_rr]

I'm not an expert at all, but i would think. maybe. that an immobiliser would either disable crank or disable injection. Or both. Possibly.
You have both, but not enough or no fuel is reaching the cylinder. I'll let you think about that for a minute

 

[badfluffy]

If its cranking over, there's only a couple of things it can be.

It's briefly firing on cold start being sprayed it, means no fuel.

Immobiliser has been bypassed and it's cranking so not likely ews at this point.

This pretty much leaves fuel pressure sensor on the fuel filter, should kick up a code but live data will show if this is working.
Camshaft sensor, will kick up a code.
Crankshaft sensor, won't kick up a code.
Injector leak off would have to be very bad not to start, should still start but be very rough.
Theres also a pressure sensor on the fuel pump/rail somewhere but that should give a code.

i had just one faulty injector which prevented the fuel rail from getting to pressure, no pressure and ecu doesnt fire injectors

 

[badfluffy]

I'm not an expert at all, but i would think. maybe. that an immobiliser would either disable crank or disable injection. Or both. Possibly.
You have both, but not enough or no fuel is reaching the cylinder. I'll let you think about that for a minute

diesel is crank disabled, petrol is fuel disabled

 

[Datatek]

Well I’ve found a used but working replacement sensor on eBay for 30 quid , might be worth a punt?

Personally I would not buy a used sensor, just another failure waiting to happen IMO. Buy a diagnostic tool so you can diagnose the fault.