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[Jan Suhr]

Yesterday my 2.6L Omega just died on me when turning in to a parking lot. Then totally dead, wouldn't start.
Called a neighbour that has a tow truck and she came and picked me up. When we have unloaded at home it started without any problem.

I assumed it was the fuel pump that had gone bad and replaced it this morning, I had a spare on the shelf.

Took it for a drive now (about 25 miles) and when almost at home it died again, in the same way. No fault engine lamp, just looks normal but wouldn't start. I waited about 15 minutes and it started up looking good.

Drove it home and checked for codes and nothing at all.

I'm confused, it is hard to know what could have gone wrong. We have kind of warm weather now but it is only about 20°C so wouldn't cause anyhting.

But apparently something shuts off and is OK after a while when it has cold down a bit.

Some sensor that is faulty?

[BazaJT]

When my Omega[a 3.0 V6] had the same issue it was the crankshaft sensor,and apparently this doesn't always throw a code.

[Jan Suhr]

Thanks,

I got the same advice from our Swedish Opel group on Facebook.

I have one spare crank sensor and I'll change it tomorrow.

[johnnydog]

I had exactly the same but on a 3.2. It began with intermittantly not cranking, but after a couple of attempts would then crank / start, until it got to the point of being totally 'dead'. Replaced the crank sensor and it started every time afterwards.
But remember - you have to buy a genuine crank sensor from genuine dealer that you genuinely have to walk into and genuinely approach the parts counter and pay the genuine parts person for the genuine part.....
But there are other sources for genuine Bosch parts who made the genuine GM crank sensor for that era of Omega

[Jan Suhr]

I had exactly the same but on a 3.2. It began with intermittantly not cranking, but after a vouple of attempts would then crank / start, until it got to the point of being totally 'dead'. Replaced the crank sensor and it started every time afterwards.
But remember - you have to buy a genuine crank sensor from genuine dealer that you genuinely have to walk into and genuinely approach the parts counter and pay the genuine parts person for the genuine part.....
But there are other sources for genuine Bosch parts who made the genuine GM crank sensor for that era of Omega

As I said, I do have one spare BOSCH 0 261 210 131 from a 3.2L that I scraped a couple of years ago. This one fit the block serial number I have.

But I will buy one anyway to have as a spare, good to have when it is needed.

[Nick W]

Crank sensor is a very real possibility, but it's such an irregular, intermittent fault that it's difficult to diagnose and know that you've fixed it. A good quality replacement is a worthwhile start. Order of preference for good quality: brand new collected from a GM dealer, removed from a running engine and immediately fitted to yours, new branded from a reputable supplier, used that you removed from a running engine some time ago, whatever new that your favourite factor supplies.


If the car just stalls, it could be the air flow meter. That is easily checked by disconnecting it and seeing if the problem improves. If it does, you need a new one. The management light will be on all the time the AFM is disconnected and will go out when you plug it back in.

[omega2018]

Check the relays in the engine bay that is an easy test and cheap quick fix.  I had the same symptoms (occasional stalls when hot, cranks but no start, starts when cooled down) in my 2.6.

My notes say

"2 stalls and refusal to start for 5 mins.  cam sensor changed (made no difference).  MAF unplugged (made no difference)."
"Bosch crank sensor installed,  second hand cam sensor installed still won't start (also old crank sensor tried and 3 pattern ones).  No fuel pressure but valve wet with fuel."
"new Bosch fuel pump bought not installed (have to remove towbar)."
"FIXED! black, passenger side engine bay fuse box" and "Drivers side purple relay fuel pump defective coil, contacts temporarily clamped shut"
"fuel pressure now checked 3.6bar at rear engine take off schraeder valve. Supposed to be about 3.7bar"

[Doctor Gollum]

The fuel pump relay has a habit of burning out on LPG equipped cars that are constantly run low on petrol.

[omega2018]

Forgot to mention it occured at 102K miles and 16 years old.  I did once run the car to empty to test the range (which was spot on - when it said 0 the car went 1 further mile then stopped).  That was 5 years earlier mind.  No LPG on my mig.

Part number is 90494959 12v 30A * Gm 90 494 959 also used on Astras, Zafiras, Saabs etc..  Pre-owned available for £5 from eBay.

I had bought a fuel pressure tester kit before solving the problem which was only £9 new and correctly showed 0 bar on the schrader valve.

[TheBoy]

Omega V6 crank sensors seem to have 2 common failure modes.

1) It just fails to start. And will never start until the sensor is replaced

2) It suddenly cuts out when hot. It will restart once cooled, but will cut out again once its warmed back up

Older V6's would throw a 19 code.


As with many GM's, using a pattern sensor is a lottery that more often and not doesn't end well.