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[berserkerboy]

What is happening when you do that with the oil?

Also is the only function of the crank sensor to control the fuel pump?

[Doctor Gollum]

What is happening when you do that with the oil?

Also is the only function of the crank sensor to control the fuel pump?

Crank sensor tells the ecu that the engine is running... Ecu cross checks with cam sensor that all is well. Then it turns on the fuel pump.

That little guide I got from a Us Bmw forum... It is a straight forward method to restore compression loss caused by borewashing... A frustrating side effect of flooding a modern engine followed by repeated attempts to start.

The Omega normally sorts itself out but yours is proving to be a moody mare, so warrants trying

[omega2018]

Possibly as that only switches off the fuel pump at cranking... Injectors are powered as they are needed for normal firing.

Pull all the spark plugs along with fuse 18.
Crank engine for 15 seconds.
Wait ten minutes.
Crank engine for 15 seconds.
Pour a tablespoon or two of oil down each plug hole.
Wait ten minutes.
Crank engine for ten seconds.
Fit new plugs and reconnect everything.
Now try and start the car.

A quid bets ten that it starts within five attempts 

i'm extremely doubtful that all the crank sensor does is tell the fuel pump to run.  it almost certainly tells the ignition system when to spark as well.  a crank sensor is a very simple thing it just tells the car the position of the crank - it doesnt tell the fuel pump one thing and the ignitions system something else.  therefore berserkerboy I think you are are right if it runs on lpg the crank sensor is working.

my recent experience is that  the crank sensor is always picked out as the fault for any non starting, especially if hasn't been bought over a counter at a dealer, even if it is a genuine bosch or delphi.    in my case it wasn't that at all but a faulty injection relay.

[omega2018]

What is happening when you do that with the oil?

It is a straight forward method to restore compression loss caused by borewashing... A frustrating side effect of flooding a modern engine followed by repeated attempts to start.

a) this is a v6 are you saying that compression has gone on all 6 cylinders at the same time?   seems very unlikely, at least one cylinder would fire
b) op says it is running on lpg OK, do you think if there was not enough compression to fire one cylinder on petrol,  all would fire OK on lpg?

[Doctor Gollum]

It supplies the ecu with information. It is perfectly feasible that the ecu uses that information as part of more than one process...

Anyway, if you bothered to read everything first rather than trying to get a reaction, you would know that the OPs car has a working fuel pump, relays (both) and crank sensor and no longer starts on lpg.

I have explained to the OP the reasoning behind my guide. I have also experienced this very issue recently with a straight six... all six plugs were so badly fouled that they wouldn't spark, and the compression was almost non existent across all six cylinders.

I will, however, humour your provocation no more

[berserkerboy]

Car battery is on charge. Will give the hard start on gas a try tomorrow. Thereafter, I will consider what to do.

[berserkerboy]

If it's the end of the road I really don't know what car will come close to an omega?

[Doctor Gollum]

Car battery is on charge. Will give the hard start on gas a try tomorrow. Thereafter, I will consider what to do.

Follow my guide, then try the hard gas start.

[Nick W]

i'm extremely doubtful that all the crank sensor does is tell the fuel pump to run.  it almost certainly tells the ignition system when to spark as well.  a crank sensor is a very simple thing it just tells the car the position of the crank - it doesn't tell the fuel pump one thing and the ignition system something else.  therefore berserkerboy I think you are are right if it runs on lpg the crank sensor is working.

my recent experience is that  the crank sensor is always picked out as the fault for any non starting, especially if hasn't been bought over a counter at a dealer, even if it is a genuine bosch or delphi.

The crank sensor supplies the engine ECU with information about the crank position; it's not connected to anything else. The ECU combines that information with that from other sensors, primarily the cam, MAF and throttle sensors and uses it to do essential stuff like ensuring that the fuel pump relay is switched on, and firing the injectors and coils at the appropriate times.  This is true of all engine management systems, and lots of them suffer from crank sensor issues. The sensors design and functionality make them particularly susceptible to manufacturing and quality control issues, which is why the advice is always the same: buying a genuine one from the appropriate dealer(it's not just Vauxhalls remember) is the best way of saving a lot of frustration.

[omega2018]

i'm extremely doubtful that all the crank sensor does is tell the fuel pump to run.  it almost certainly tells the ignition system when to spark as well.  a crank sensor is a very simple thing it just tells the car the position of the crank - it doesn't tell the fuel pump one thing and the ignition system something else.  therefore berserkerboy I think you are are right if it runs on lpg the crank sensor is working.

my recent experience is that  the crank sensor is always picked out as the fault for any non starting, especially if hasn't been bought over a counter at a dealer, even if it is a genuine bosch or delphi.

The crank sensor supplies the engine ECU with information about the crank position; it's not connected to anything else. The ECU combines that information with that from other sensors, primarily the cam, MAF and throttle sensors and uses it to do essential stuff like ensuring that the fuel pump relay is switched on, and firing the injectors and coils at the appropriate times.  This is true of all engine management systems, and lots of them suffer from crank sensor issues. The sensors design and functionality make them particularly susceptible to manufacturing and quality control issues, which is why the advice is always the same: buying a genuine one from the appropriate dealer(it's not just Vauxhalls remember) is the best way of saving a lot of frustration.

so,  getting back to the point,  beserkerboy you are spot on - "If the crank sensor was faulty it wouldn't have run on gas "  .

or in case people are really picky as they sometimes can be here, a dodgy crank sensor would give the same problems on gas as on petrol. yes it might fail intermittently but it would fail intermittently under gas as well as petrol.

[omega2018]

I know how frustrating error tracking can be.  just going back to the beginning of this and the errors codes you got:

"P0650 (4) unknown present
P0430 (1) unknown present
P0420 (1) unknown not present
P1612 (0) unknown not present

cleared faults and attempted to start again with no luck.

P0650 showed up again."

420 and 430 are 'cat efficiency below threshold' both banks and probably is a symptom of trying to fire with with no petrol, not a cause
1612 'immobiliser wrong or no signal' is also likely a symptom - i got '1613 immobiliser wrong or no signal' during my stall/no start problems and I'm sure it was triggered by a low battery voltage during attempted starting.  certainly I haven't had immobiliser issues since i fixed the relay.

so that leaves 650.  also the others cleared but 650 kept coming back.  so 650 is of interest. 

yes it could be caused by the Malfunction Indicator Lamp circuit but if so I would expect you to have had it long before all these problems.  assuming its appearance does coincide with the problems, 650 can be caused by a 'failed/faulty PCM (Powertrain control module)' , i.e. the electronic fuel injection system control (ecu). 

you may be able to pick up a used one for £40 or so and it looks easy to physically swap, may need programming to the vehicle though, ask oof.. 

double check but i think this may be the correct part for your 3.2 www.ebay.co.uk/itm/282541427589

yes i know this would likely affect gas operation too so that remains a puzzle but I don't know much at all about gas installs and their electronics.  anyway  the ecu is orders of magnitudes more sophisticated than a crank sensor and the petrol supply may be affected by it whereas gas may not.  or the gas install may control the spark independently.   a crank sensor just tells everybody and anybody where the crank is.  or not.

[omega2018]

or could be this one, £35 www.ebay.co.uk/itm/201577994490 , offering full refund if any problem

best get one with the immobiliser ring, transponder chip and code, sometimes they sell on oof.

[Migv6 le Frog Fan]

Top one is the wrong one, bottom one could be the right one , but they are both expensive paperweights in effect. ECU needs to include key chip and immobiliser ariel.
While engine ECU,s are normally very reliable, I have seen a 3.2 and a 2.6 display similar problems to the ones described cured by a replacement ECU.
I'm not saying that's what the problem is though. It really needs a tech 2 session imo.
Failing that, another Omega to try swapping parts over to confirm or rule out suspected components.

[TheBoy]

Do NOT buy an ECU. Its not the ECU, any more than its a crank sensor.

The thing runs as expected on gas, and the gas ECU is just a piggy back of the main ECU.  So that's all a load of ill considered guff.

Also, P0650 is safe to ignore (have you checked the bulb?).


When its running on gas, what happens if you switch to petrol, does it immediately stall?

[omega2018]

The thing runs as expected on gas, and the gas ECU is just a piggy back of the main ECU.  So that's all a load of ill considered guff.

Also, P0650 is safe to ignore (have you checked the bulb?).

https://www.obd-codes.com/p0650:

"Potential causes may include:
Burned out MIL bulb/LED
MIL wiring problem (short or open electrical condition)
Poor electrical connection at the bulb/cluster/
PCM Failed/faulty PCM"