Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Undiscovered on 06 August 2019, 12:10:39

Title: Lumpy idle and stalling
Post by: Undiscovered on 06 August 2019, 12:10:39
I have an Omega, 3L V6 Auto. W plate 2000reg.
Lpg converted.

Fortnight or so ago, it stalled while in a car park, looking for a space (tick over revs, low speed). Fired back up immediately. Switched it to petrol, no issues.

Later on that day, stalled again, em light lit, wouldn't fire. Waited 10-15 mins, fired up. Sounded rough, like crap in fuel so got gallon of petrol in it- usually run it on quarter tank as lpg.

Fired up sounded fine. Pulled off drive, stalled. em light lit.
Mate reckoned crank sensor. Garage diagnosed n replaced crank sensor. Couldn't recreate fault.

Picked it up yesterday. Sounded sweet, drove fine. Got home, stalled on drive. Lumpy idle.
Ticks over at 500rpm, then stalls. Starts up straight away, then 30s later, stalls. Em light lit. Repeat twice, then fine. If I rev it, seems fine. Not moved it from driveway as it was a bugger to push home last time.
I'll post the paperclip trick diagnostics tonight.

Any ideas? I'm on holiday in a fortnight n really need the car!
Title: Re: Lumpy idle and stalling
Post by: Migv6 le Frog Fan on 06 August 2019, 12:34:28
So the problem only occurs on LPG and its fine on petrol ? If it happens on both first action would be to clean out the idle control valve - sits on the o/s of the plenum. Clean out with carb cleaner, petrol or similar. Then a few drops of light oil dropped into it to prevent it becoming sticky.
If its an LPG only problem, there are a few experts on here, but you might have to wait a while for them to pop up and offer advice.
Title: Re: Lumpy idle and stalling
Post by: terry paget on 06 August 2019, 12:46:33
Could be MAF (mass air flow) sensor. Easy to check, unplug it and drive the car. EML will be on, but if it cures the fault, you will have found what's wrong.

Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 06 August 2019, 12:49:19
Problem initially happened on lpg, so switched it to run on petrol and kept it on petrol since.
It runs on petrol at startup before autoswitching, when enabled, to lpg.

It takes awhile to switch to LPG when idling, and I don't want to be doing further damage to the engine in that time.
It was my LPG fitter who said crank sensor issues.

Will try mass air flow sensor later on too. It almost feels if the car is hunting before it stalls.
Title: Re: Lumpy idle and stalling
Post by: Doctor Gollum on 06 August 2019, 14:55:04
A non genuine crank sensor, from a non genuine supplier that you didn't walk into will work once. Might last a week, or possibly even a year, but ultimately it will be a waste of money :'(
Title: Re: Lumpy idle and stalling
Post by: Raeturbo on 06 August 2019, 15:04:42
Will it run ok on petroleum?
Title: Re: Lumpy idle and stalling
Post by: Doctor Gollum on 06 August 2019, 15:41:32
Paper clip it and report back :y

Crank sensor code is normal when not running, so might lead someone unfamiliar with the Omega to conclude it is faulty ;)
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 06 August 2019, 20:31:11
Ignition on and running, both show code 19. Incorrect rpm signal.
When revs drop to 5-600, it's normal idle speed, cuts out.

With maf sensor unplugged, car seems less lumpy, still shows code 19 and cuts out at the same rpm.

Any ideas.
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 06 August 2019, 20:41:17
Got an assistant to give it rev while I had a look about under the bonnet- there's a persistent ticking from the rear offside cylinder.
Thinking a misfire?
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 06 August 2019, 21:16:02
From looking through the forum, seems could be still the crank sensor, either worn wiring or non-GM part.
Title: Re: Lumpy idle and stalling
Post by: Migv6 le Frog Fan on 06 August 2019, 23:37:42
Idle control valve
Crank sensor
Dispack rusted causing misfire
Dispack and/ or plug leads fried due to oil in plug wells, from leaking camcover gaskets
MAF sensor......
Title: Re: Lumpy idle and stalling
Post by: Doctor Gollum on 07 August 2019, 02:15:52
Plugs or leads first off :y

Lpg is far less tolerant of weak spark...

Pull the plugs and report back :y
Title: Re: Lumpy idle and stalling
Post by: Enceladus on 07 August 2019, 02:38:14
Ignition on and running, both show code 19. Incorrect rpm signal.
When revs drop to 5-600, it's normal idle speed, cuts out.

With maf sensor unplugged, car seems less lumpy, still shows code 19 and cuts out at the same rpm.

Any ideas.
Fault code 19 with ignition on and also when engine running indicates that the crank sensor is (still) bad.
You should see code 31 with ignition on and this should disappear when the engine is started. 31 = no rpm signal.

It might be that the garage have fitted an incorrect type of sensor for your engine/ECU combination. Where did they get the replacement from? Did they give you back the old sensor? Look at the head.

Assuming your old sensor was a Bosch with an oval sided plug then you need  GM 90540743 which will be marked GM & Bosch 0 261 210 131.
The other sensor with the same cable and oval sided plug that's made by Delphi or Siemens won't work properly even though it fits perfectly. It has lower resistance.

Sort the crank sensor first.
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 07 August 2019, 03:49:29
I'll check the sensor when I get back from work later. From what I can gather, it should be on the front of the engine.
Vehicle had new plugs, and had a leaky cam cover replaced 2months back and has been fine on both LPG and petrol, though this is something to consider.
 All of these problems are when running on petrol- as long as it goes, I can get away on holiday!
Title: Re: Lumpy idle and stalling
Post by: BazaJT on 07 August 2019, 07:51:51
Crank sensor is at side of oil filter[engine end]with electrical plug behind nearside cylinder head,front of engine are the cam sensors.
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 07 August 2019, 18:20:57
Spoke to the garage and the old sensor was a Bosch.
Not sure what it was replaced with (mech is on holiday) but it defo wouldn't be Bosch. Part cost is way too low.
So, will source a Bosch crank sensor and see where we go. Seen some on Ebay and Amazon tho may just go to local Vauxhall dealer.
Title: Re: Lumpy idle and stalling
Post by: TheBoy on 07 August 2019, 18:58:56
A 19 is bad news on these.

A 3.0l sensor from a dealer on Tradeclub is about £50.  Personally, I *ALWAYS* carry a spare crank sensor in the boot, which has saved me the hassle of having to arrange a tow in the past.
Title: Re: Lumpy idle and stalling
Post by: Doctor Gollum on 07 August 2019, 19:40:03
Spoke to the garage and the old sensor was a Bosch.
Not sure what it was replaced with (mech is on holiday) but it defo wouldn't be Bosch. Part cost is way too low.
So, will source a Bosch crank sensor and see where we go. Seen some on Ebay and Amazon tho may just go to local Vauxhall dealer.
Go to a genuine Vauxhall dealer that you genuinely have to walk into in order to buy your replacement. Anything else will be a further waste of time/money ;)
Title: Re: Lumpy idle and stalling
Post by: Raeturbo on 07 August 2019, 20:19:35
^^^^^^ I agree with the above it’s hard to trust any of the so called genuine sellers these days.
Title: Re: Lumpy idle and stalling
Post by: Enceladus on 08 August 2019, 14:07:43
Assuming you have a local Vauxhall dealer that still does parts then phone first. If this sensor was not carried over to another vehicle after the Omega ceased production then it will be obsolete and unlikely to be still stocked. Vauxhall discontinued any remaining Omega unique parts well over a year ago. Anything left was sold off to whomsoever would have it. But you might strike lucky and find one still in stock or it might be available special order from Germany.

Regardless of where you get it, the part you need should be marked on the head with the Bosch logo and the number '0 261 210 131'.
It may or may not also have a GM logo. These parts might additionally be marked 90494182 which is the internal factory assembly number.
The GM Opel/Vauxhall aftermarket part number actually used to identify and buy the sensor is 90540743.

Other parts that have a GM logo and are marked with part number '90 492 061' won't work reliably. These are 540Ω as opposed to the Bosch's 860Ω. These require an earlier revision of the Motronic ECU.
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 09 August 2019, 13:28:53
Popped in yesterday to the local dealer.. The part is now on order from Germany n will be here in 7-10days. when it arrives, I'll have a word with the mech and hopefully he'll pop out n fit it for me.

It's V009050743, which I assume is the same as the GM part. Chap at the counter said it was.
Oddly they don't do trade club any more, but he knocked off 10% anyway.
Title: Re: Lumpy idle and stalling
Post by: Enceladus on 09 August 2019, 17:07:57
More and more dealers are pulling out of the Trade Club scheme, so I'm not surprised. And in any event since this part is now special order from Germany, it has likely dropped off the TC scheme.
The part-number looks good.
How much did you have to pay?
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 10 August 2019, 11:42:40
£80 inc VAT.
The incorrect sensor was half that, and even that took three days to source. It's one if them things that, unless you have specific knowledge, you'd never think. Which is why main dealers charge so much... I trust my mechanic- he's seen me right in the past.
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 18 August 2019, 18:25:42
Well, sensor replaced yesterday and everything seems fine.
Drove it for a few local miles, just in case, to bring it up to temp. Hopefully, that's the issue cured.
Have to say, my mechanic was very sceptical that the sensor was at fault.

I have noticed tho that, the date keeps resetting back to 2000 on switching ignition on. Time is fine.
Will this cure itself once ecu clears the fault code?
Title: Re: Lumpy idle and stalling
Post by: Shackeng on 18 August 2019, 19:23:30
Well, sensor replaced yesterday and everything seems fine.
Drove it for a few local miles, just in case, to bring it up to temp. Hopefully, that's the issue cured.
Have to say, my mechanic was very sceptical that the sensor was at fault.

I have noticed tho that, the date keeps resetting back to 2000 on switching ignition on. Time is fine.
Will this cure itself once ecu clears the fault code?

Which is why the accumulated wisdom on here is worth listening to. :y
Title: Re: Lumpy idle and stalling
Post by: Nick W on 18 August 2019, 21:33:07
Well, sensor replaced yesterday and everything seems fine.
Drove it for a few local miles, just in case, to bring it up to temp. Hopefully, that's the issue cured.
Have to say, my mechanic was very sceptical that the sensor was at fault.



I can't imagine why, as fitting a genuine crank sensor bought over the counter at a main dealer is SOP for any marque.
Title: Re: Lumpy idle and stalling
Post by: Enceladus on 19 August 2019, 14:52:41
Well, sensor replaced yesterday and everything seems fine.
Drove it for a few local miles, just in case, to bring it up to temp. Hopefully, that's the issue cured.
Have to say, my mechanic was very sceptical that the sensor was at fault.

I have noticed tho that, the date keeps resetting back to 2000 on switching ignition on. Time is fine.
Will this cure itself once ecu clears the fault code?
Did you retrieve the 'faulty' sensor? If yes, then please post up a picture of the numbers on the head? So we can all see what doesn't work.

As to the date issue. That can't have anything to do with engine fault codes. Try tuning to a national BBC station and then switching off RDS for a minute and then switching it on again. User Drewomega seems to have a similar issue. See the Electrical and Audio Help sub-forum.

And are you saying that you still have a fault code? What codes are still present and does the EML stay illuminated when the engine is started?
Title: Re: Lumpy idle and stalling
Post by: Undiscovered on 21 August 2019, 20:54:38
No, no fault codes now.
Filled her up with decent fuel n want out for a good long drive yesterday. Engine is fine and running perfectly, which is a massive relief.
I'm not sure what the incorrect sensor looked like- the new Vauxhall one has the same code stamped on it as mentioned in an earlier post, but is made in Romania, rather than Germany.
As for the time constantly resetting, I'm sure it'll sort itself in the end.

Huge thanks to everyone who has provided advice and help over the past few weeks. It is very much appreciated.
Title: Re: Lumpy idle and stalling
Post by: Shackeng on 22 August 2019, 16:36:42
No, no fault codes now.
Filled her up with decent fuel n want out for a good long drive yesterday. Engine is fine and running perfectly, which is a massive relief.
I'm not sure what the incorrect sensor looked like- the new Vauxhall one has the same code stamped on it as mentioned in an earlier post, but is made in Romania, rather than Germany.
As for the time constantly resetting, I'm sure it'll sort itself in the end.

Huge thanks to everyone who has provided advice and help over the past few weeks. It is very much appreciated.

Call me a cynic, but, on the rare occasions I need garage assistance, and depending on the work required, I often ask them to put the faulty item(s) in the boot, (unless it's a donk change ::)), as I like to see why it/they needed changing. :y
Title: Re: Lumpy idle and stalling
Post by: TheBoy on 22 August 2019, 17:09:45
There is a lot of fake big brand items out there. And fake sensors are known to be extremely problematic in Omegas.  Hence the advice to walk into a Vauxhall/Opel franchised dealer to get the real part.
Title: Re: Lumpy idle and stalling
Post by: Nick W on 22 August 2019, 23:45:16
There is a lot of fake big brand items out there. And fake sensors are known to be extremely problematic in Omegas engine management systems.  Hence the advice to walk into a Vauxhall/Opel franchised dealer to get the real part.


That's what you meant, without being so parochial. :y