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[johnnydog]

My starting woes are continuing.....
On my 2.6, my intermittant starting has continued. Two crank sensors, a fuel pump relay, and I thought the 2nd crank sensor had sorted it. My thoughts then went to the immobiliser. Intermittantly, it would just crank but not fire as previously. Maybe coincidence, but using the spare key seemed to rectify the issue. If using the original key, it occasionally wouldnt start, but if I tried the spare, it generally started ok. Until today.
Tried the original key, and it just cranked. Tried the spare and it fired up, as it has done previously. On my 5 mile trip, on the motorway at around 70mph, it suddenly 'died' momentarily, not a misfire, but similar to the engine cutting out - the EML light came on briefly, and the engine immediately fired again, as normal, and after a couple of seconds the EML went out.
Left the engine running at my destination for around 10 minutes (didn't want to switch off...), and then set off - over the next mile, the same symptoms happened again 4 times around 30 mph - the engine cutting out momentarily, and the EML coming on for a second or so, before firing up again - until I slowed to stop at a junction. The engine cut out completely as I came to a stop. Took the key out of ignition, locked it, unlocked it, tried starting the engine and it fired. It then ran perfectly for the 5 miles home.
Checked the codes -
ABS traction control 2 faults
1 - Canbus not communicating with ECM - U2105-4
2 - Engine torque reduction incorrect signal - C0241-4

Antitheft 2 codes
125 present
128 Not present ( an old code?)

Cleared the codes, the antitheft codes went, but it then read 'Unable to communicate with ECM'
At this point when the ignition was on, the spanner light and EML were flashing alternately very quickly, not brightly, but quite visible. Tried to crank the engine, and it fired, and ran for about a second before cutting out.
With the ignition on, the throttle body was clicking loudly quite merrily, and this was  continuous whilst the ignition was switched on. Switched off, and back on again, and the clicking continued...
I have read topics 121307.0 3.2 Elite No Start 5th Feb 2014, and 16628.0 3.2 Won't Start, but I just wondered if anyone had any thoughts on this one.....?  It's driving me nuts....

[Doctor Gollum]

How many keys on the keyring being used? More than one chip in close proximity can confuse the transponder.

Any notable difference between the key blades being used?

[johnnydog]

The keys are on their own individual key rings with no other keys. The one I'm not using / trying is generally in my jacket pocket whilst the other is in the ignition.

[johnnydog]

How many keys on the keyring being used? More than one chip in close proximity can confuse the transponder.

Any notable difference between the key blades being used?

No particular wear on either. One has seen more use than the other for obvious reasons, but nothing significant.

As regards two keys being used near to each other, I regularly deliver vehicles that have two keys on the same fob in the ignition, or two together in the centre console if keyless ignition, or have two keys in very close proximity to each other, i.e one in the ignition, the other in the centre console, but I have never experienced issues that would suggest symptoms as above caused by two keys close to each other. Not that any are Omegas though.....

[TheBoy]

Immobiliser fault will not shut down a running engine.


Not clear from initial post, any engine codes?

[dave the builder]

Ignoring the anti-theft codes (maybe these are unrelated and due to swapping between keys )
Also ignoring the ABS/traction faults (maybe because the calculated stalled engine speed did not match the speed of ABS ,gearbox etc )  the symptoms are just like what I had a while back .
Fuel delivery (lack of )
I ordered a new Bosch pump ,but when I went to fit it ,noticed a split in the fuel line between the outlet of the pump and the metal pipe of the pump assembly 
the split in the pipe must open up occasionally and pumping the fuel back into the tank , so no external evidence of a leak .

the fuel line was deteriorated ,but again ,no visual evidence because the pipe is inside the tank  .

not saying you have a dab pipe , it could be the pump itself perhaps ,or wiring issue 

mine's a 53 plate 2.6 saloon CDXi ,not that the above couldn't happen to any model

if you get a crank but no start ,maybe try cracking open the 19mm fuel union that sits above 1.3.5 

NO squirty = fuel pump NO worky 

[johnnydog]

The only codes were those I stated in post #1 TB.
Thanks D the B for your suggestions.
Tried starting it today, and it started 1st churn, although the churn took longer than normal. It ticked over with no throttle body clicking for about a minute then just died.
Key out, locked it, unlocked it, key in, cranked, and it fired - again not as quickly as normal, but then the flashing spanner and EML started. The traction control light also came on. Tried to drive off, but it seemed to be in limp mode, before just dying.
Got it on a slight downhill and when started, it would pull away to around 10 /15 mph but when the revs got up to about 1500, it would just cut out, the EML came on, and that was it. It would start again with a long crank, but trying to pull away under the slightest bit of power, it would just die.
Took a video of the antics of the dash lights  but not sure how to post it on here.
I am convinced it is ECU related from reading the very helpful topics, some going back 8 years.
I have since spoken to a very knowledgeable ex VX autoelectrician, who I have used previously, described the symptoms, and with no hesitation he immediately said  'ECU - definately'.
This concurs with the info I've read about the exact same symptoms on here.
Do others agree - any thoughts appreciated before I try to find a replacement?

[Doctor Gollum]

It wouldn't be the first engine loom to fail. Have changed three on mine and other cars.

You can rule out the ecu by using a n other 2.6/3.2 ecu + transponder + chip from the car parked next to it.

Only caveat is that you mark the parts carefully from the faulty car and put them safely in the house in a taped shut tin before you do anything else.

This isn't out of paranoia, or some Yrumpist conspiracy but to make it as unlikely as possible to fit a mismatch of parts to either car as both will become ornaments until you unravel the resulting carnage.

If the fault remains, then you new the original ecu isn't the problem.

[Doctor Gollum]

As a side note have you run through Kevin's excellent Starting/Charging guide?

If not, do so. To the letter and report back.

[Raeturbo]

I’d go With Dai, he’s a builder after all👍 We’re clever👍🤣

[johnnydog]

As a side note have you run through Kevin's excellent Starting/Charging guide?

If not, do so. To the letter and report back.

Having previously read this excellent guide, unless I'm missing something, I'm not sure this is applicable with the symptoms my car has? But please tell me why you think it is? The alternator is charging correctly, and the battery is very strong despite the repeated cranking over the last few days.

[Doctor Gollum]

Unless you have run the tests, how do you know that? Just because the car starts and the alternator light goes out does not guarantee that everything is ticketyboo.

Discrepancies can do strange things to a car, even an Omega. And it's a free check if only to be sure.

Equally, if you are adament that the ecu is faulty that is also an easy check if you have more than one Omega and I  wouldn't simply swallow the 'It's the Ecu' diagnosis, especially if it's given remotely. A new ecu is the pinnacle of scatterbomb parts replacement and I doubt it will actually solve the problem.

[Andy H]

Ignoring the anti-theft codes (maybe these are unrelated and due to swapping between keys )
Also ignoring the ABS/traction faults (maybe because the calculated stalled engine speed did not match the speed of ABS ,gearbox etc )  the symptoms are just like what I had a while back .
Fuel delivery (lack of )
I ordered a new Bosch pump ,but when I went to fit it ,noticed a split in the fuel line between the outlet of the pump and the metal pipe of the pump assembly 
the split in the pipe must open up occasionally and pumping the fuel back into the tank , so no external evidence of a leak .

the fuel line was deteriorated ,but again ,no visual evidence because the pipe is inside the tank  .

not saying you have a dab pipe , it could be the pump itself perhaps ,or wiring issue 

mine's a 53 plate 2.6 saloon CDXi ,not that the above couldn't happen to any model

if you get a crank but no start ,maybe try cracking open the 19mm fuel union that sits above 1.3.5 

NO squirty = fuel pump NO worky 

The ECU doesn't run the pump until it senses pulses from the crank sensor. (unlike some, VW for example, that pulse the pump when you first turn the key to pressurise the fuel pipework)

[dave the builder]

Ignoring the anti-theft codes (maybe these are unrelated and due to swapping between keys )
Also ignoring the ABS/traction faults (maybe because the calculated stalled engine speed did not match the speed of ABS ,gearbox etc )  the symptoms are just like what I had a while back .
Fuel delivery (lack of )
I ordered a new Bosch pump ,but when I went to fit it ,noticed a split in the fuel line between the outlet of the pump and the metal pipe of the pump assembly 
the split in the pipe must open up occasionally and pumping the fuel back into the tank , so no external evidence of a leak .

the fuel line was deteriorated ,but again ,no visual evidence because the pipe is inside the tank  .

not saying you have a dab pipe , it could be the pump itself perhaps ,or wiring issue 

mine's a 53 plate 2.6 saloon CDXi ,not that the above couldn't happen to any model

if you get a crank but no start ,maybe try cracking open the 19mm fuel union that sits above 1.3.5 

NO squirty = fuel pump NO worky 

The ECU doesn't run the pump until it senses pulses from the crank sensor. (unlike some, VW for example, that pulse the pump when you first turn the key to pressurise the fuel pipework)

Yes
but 
 if you have cranked the engine and it's failed to start then the pump will have pressurised the rail
so cracking the union above 1.3.5 should squirt fuel *

*provided you don't leave it ages after cranking ,no leaks and the pump is pumping

[Andy H]

Ignoring the anti-theft codes (maybe these are unrelated and due to swapping between keys )
Also ignoring the ABS/traction faults (maybe because the calculated stalled engine speed did not match the speed of ABS ,gearbox etc )  the symptoms are just like what I had a while back .
Fuel delivery (lack of )
I ordered a new Bosch pump ,but when I went to fit it ,noticed a split in the fuel line between the outlet of the pump and the metal pipe of the pump assembly 
the split in the pipe must open up occasionally and pumping the fuel back into the tank , so no external evidence of a leak .

the fuel line was deteriorated ,but again ,no visual evidence because the pipe is inside the tank  .

not saying you have a dab pipe , it could be the pump itself perhaps ,or wiring issue 

mine's a 53 plate 2.6 saloon CDXi ,not that the above couldn't happen to any model

if you get a crank but no start ,maybe try cracking open the 19mm fuel union that sits above 1.3.5 

NO squirty = fuel pump NO worky 

The ECU doesn't run the pump until it senses pulses from the crank sensor. (unlike some, VW for example, that pulse the pump when you first turn the key to pressurise the fuel pipework)

Yes
but 
 if you have cranked the engine and it's failed to start then the pump will have pressurised the rail
so cracking the union above 1.3.5 should squirt fuel *

*provided you don't leave it ages after cranking ,no leaks and the pump is pumping

The pump won't run if the if the ECU doesn't see pulses from the crank sensor. Don't assume that cranking the engine will cause the pump to run (even though it should).
Over 14 years & 170,000 miles I had 3 'failure to proceed' events caused by the crank sensor failing. (I also had charging problems due ageing wiring and a blown alternator regulator.)
The cars are older now so there will be failure modes that I didn't see in a 10 year old car.

[Stu.C]

If you've doubts about the fuel pump, could you not loosen off the fuel line going into 1,3,5 and then jumper the pink pump relay (in the engine bay) ... ?

[cam.in.head]

hi john.
various suggestions have been put forward above and its one of those "not obvious" faults that we come across now and again. hardest to find when theyre not consistent.you have possibly eliminated crank sensor now ( you would hope) so its down to another faulty component ,wiring issue,or connection issue.
as mentioned  looms can be getting more brittle now especially in the engine compartment but to me (and suggested) it might be at the stage where you can swap parts from your other omega to eliminate.    but first.
worth checking carefully all leads out of the battery to and from the battery mounted fusebox.
earth connections under the battery and around the place.
connections inside the relay box / relay sockets etc.ecu plug.ecu earth.
multi round connectors near the battery.
just to be sure .it would be nice if wiggling these whilst engine running showed the fault but most likely not !.
injection and fuel pump relays can be swapped ,and if no difference can stay where they are.
if you dont mind this part swapping idea then the ecu and ring would at least check that part of it for elimination purposes ( or be the issue)

[johnnydog]

Thanks for all the suggestions Chris. I am hoping to have a further play tomorrow, although I have also now managed to get hold of another 2.6 ECU to try (as a last resort with help of programming by the very knowledgeable auto electrician) if all else doesn't reveal any likely culprits.

[Fraggles Rock]

The 3.2 ecu from one of your existing cars that is known to work correctly would have sufficed.

A second hand unknown one may introduce other issues.

Also, don't forget that you also need the matched chip and transponder for this acquired ecu.

[johnnydog]

The 3.2 ecu from one of your existing cars that is known to work correctly would have sufficed.

A second hand unknown one may introduce other issues.

Also, don't forget that you also need the matched chip and transponder for this acquired ecu.

If it comes to using this replacement ECU, then 'my man' doesn't need the transponder chip and transponder. He states he can wipe it, and then reprogram it to my car. He did another for me several years ago on a 3.2, presented with just the replacement ECU, and it has been fine ever since. He was recommended to me then by several technicians at VX as being the 'man for the job'.
See what else I can find before that stage though.

[johnnydog]

...... and I wouldn't simply swallow the 'It's the Ecu' diagnosis, especially if it's given remotely. A new ecu is the pinnacle of scatterbomb parts replacement and I doubt it will actually solve the problem.

Just a quick update on this saga. Took the Omega to my 'ECU definitely' man. The fault was as he diagnosed - the ECU was goosed. Apparantly, new ones are on back order at VX, and are well over a grand, plus VAT when available.
He has previously successfully wiped and reprogrammed used 2.2's and 3.2's ECUs in the past, but he struggled with the used 2.6 ECU I got for some reason. Fortunately he managed to find a brand new boxed GM unit 'gathering dust' at a fraction of the cost, programmed it, and now the car is starting and running as sweet as a nut - like the proverbial sewing machine
Seems like the intermittant non starting issues, that had got progressively worse since the start of this saga, were nothing other than the start of the ECU failing, and throwing red herrings into the mix. Fortunately other informative topics on here with similar starting issues also pointed towards the ECU failing.
Experience in a particular field is always invaluable in diagnosing symptoms relative to an actual fault, and the recommendation of this particular auto electrician above all others by other VX technicians being a good indication of his ability....

[Doctor Gollum]

I still wouldn't rule out the loom, based on experience having replaced more looms than ecus (4-0), but it sounds like it's sorted.

[johnnydog]

After a few days of use, I would say now the problem definately wasn't anything to do with the loom - the car has started instantly first and everytime since its new ECU was fitted and is now running beautifully.
I appreciate the suggestions for possible culprits though
Although still a strange one why the ECU did give up the ghost - damp possibly? Although it was a gradual / intermittent failure, whereas the one on my 3.2 about 7 years ago was an immediate failure of the ECU due to a battery failure probably resulting in a 'spike'.
Good though to be up and running with a brand new GM ECU at what I consider to be a very reasonable cost

[biggriffin]

The earth's under battery box corrode,as does the joint in loom.

[johnnydog]

As per Chris' suggestion in post #16 -  earths checked and are remarkably clean and rust free