Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: AndyT on 29 August 2007, 21:36:08

Title: 2.5 V6 won't run
Post by: AndyT on 29 August 2007, 21:36:08
My Omega is a 2.5 V6 CDX Auto.
 :( HELP!!  :( After thousands of miles not missing a beat, yesterday it started to idle a bit rough and to hunt. I ignored it and carried on with my journey cruising at a nice steady 70 down the motorway on cruise control. Then after about 20 miles it started missing, a little at first and then over the next 10 miles it got worse until it died altogether. No way would it start and I had to call for rescue to get home.
Today I tried again to start it. Every time it just fired up and died immediately. Only once did it run for about 10 secs then died as soon as I touched the accelerator. Noted that all the warning lights went out as normal.
I suspected a fuel feed problem. I removed the petrol feed and return pipes at the engine and stuck them in a jar whilst cranking. Petrol came through OK. I checked the fuses, especially fuse 16 - all OK. I checked all other electrical connections but it made no difference.
Any ideas?
Could it be one of the sensors? - which one?
Andy T
Title: Re: 2.5 V6 won't run
Post by: cem_devecioglu on 29 August 2007, 21:45:06
Before the sensors..Do you have EML light..Whats the mileage..

Can be crank sensor or anything at first sight..But ECU codes must be checked
Title: Re: 2.5 V6 won't run
Post by: Danny on 29 August 2007, 21:45:08
EML lit at any point??
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 07:28:20

EML light was not showing while it was still running. And on the one time when I got it fired up for about 10 secs it went out almost straight away - like usual.
Andy T
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 07:29:13
oh - and mileage is 103k
Title: Re: 2.5 V6 won't run
Post by: JamesV6CDX on 30 August 2007, 07:45:09
It does sound like fuel starvation.

Is fuse 18 OK, (note, 18, NOT 16!) and is there fuel in the tank?
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 08:30:32
Do a paperclip test anyway, and post back results....

Additionally, check plug wells for signs of oil.
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 09:02:58
Sorry misprint - yes I checked fuse 18 and it was OK.
There is fuel in the tank (not a lot - about 15 litres) - is it worth putting another 20 litres in (I read on this forum somewhere that a failing pump can stop working if the level drops below 1/4 full).
Plug wells look dry ( at least on the bank you can get to easily - cam gaskets were changed about 2000m ago (with genuine VX ones).
Will get the paperclip out tonight and report back.
Andy T
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 09:15:07
Quote
Sorry misprint - yes I checked fuse 18 and it was OK.
There is fuel in the tank (not a lot - about 15 litres) - is it worth putting another 20 litres in (I read on this forum somewhere that a failing pump can stop working if the level drops below 1/4 full).
Plug wells look dry ( at least on the bank you can get to easily - cam gaskets were changed about 2000m ago (with genuine VX ones).
Will get the paperclip out tonight and report back.
Andy T
failing pump, you wouldn't get fuel at fuel rail (diesels, the tank pump is purely a lift pump, but in petrols its much more important)
Title: Re: 2.5 V6 won't run
Post by: Martin_1962 on 30 August 2007, 10:03:04
I suspect crank sensor, does it start at all if left for a few hours?
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 10:26:20
Martin,
No - makes no difference how long it stands - just fires up and dies instantly.
Andy T
Title: Re: 2.5 V6 won't run
Post by: cem_devecioglu on 30 August 2007, 12:02:18
Your problem seems to be ECU stopping ignition.


Anyway crank sensors are cheap..Will worth checking with a new one...

Title: Re: 2.5 V6 won't run
Post by: ians on 30 August 2007, 12:12:47
Quote

Anyway crank sensors are cheap..


are they?  I thought they were c 50 quid give or take..  for me that is a lot for just experimenting without knowing it will fix the problem.

Anyway surely the paperclip will show up the problem if its crank sensor..?
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 13:38:02
paperclip may or may not be conclusive....   ....post up results of test, and we can ponder it...
Title: Re: 2.5 V6 won't run
Post by: cem_devecioglu on 30 August 2007, 13:39:31
Quote
Quote

Anyway crank sensors are cheap..


are they?  I thought they were c 50 quid give or take..  for me that is a lot for just experimenting without knowing it will fix the problem.

Anyway surely the paperclip will show up the problem if its crank sensor..?

Here I buy for 35 £ ..This is the most critical part that will let you with a 1.6 tons of non moving metal in the middle of the road..

if you dont like surprises and to pay for the carrier truck its better to pay for that I think..

Also note that even without any problem I think changing this sensor is a preventive action..If you go to the service with car on truck the prices really change. :(
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 14:46:43
Quote
Quote
Quote

Anyway crank sensors are cheap..


are they?  I thought they were c 50 quid give or take..  for me that is a lot for just experimenting without knowing it will fix the problem.

Anyway surely the paperclip will show up the problem if its crank sensor..?

Here I buy for 35 £ ..This is the most critical part that will let you with a 1.6 tons of non moving metal in the middle of the road..

if you dont like surprises and to pay for the carrier truck its better to pay for that I think..

Also note that even without any problem I think changing this sensor is a preventive action..If you go to the service with car on truck the prices really change. :(
I agree with carrying spare in car (after I broke down in France), but wouldn't change as preventative measure, unless you were getting code 19...
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 20:31:38
Did the paperclip test and I am only getting code 31.
I believe this is 'no rpm signal' - don't you always get this when the engine is not running? Obviously I can't run the engine to see if it goes away.
Any help?
Andy T
Title: Re: 2.5 V6 won't run
Post by: cem_devecioglu on 30 August 2007, 20:50:45
I searched the net :

here are the answers

http://wiki.answers.com/Q/What_would_cause_a_car_to_start_then_die_and_then_not_start_again_for_a_few_hours

note that my money is on the crank sensor still..  By the way what was the mileage
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 20:54:41
Quote
Did the paperclip test and I am only getting code 31.
I believe this is 'no rpm signal' - don't you always get this when the engine is not running? Obviously I can't run the engine to see if it goes away.
Any help?
Andy T
31 normal.  if you can get car to run for a few mins, retry test with engine running....


may be time to check plugs to see if running rich/lean...
Title: Re: 2.5 V6 won't run
Post by: AndyT on 30 August 2007, 21:36:06
No chance - it will not run, just fires and dies. I guess the plugs will be covered with all sorts of rubish after so many attempts to start.
When this problem first started, there was no EMU light showing, the usually smooth idle was just a little rough, with the idle speed rising and falling. The only time I saw the light come on was when travelling at speed shortly before it stopped for good - and then the light only flashed on for a second or two.
Andy T
 >:(
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 30 August 2007, 21:50:54
can you gently peel back cambelt cover, ensure cambelt still goes round....
Title: Re: 2.5 V6 won't run
Post by: Nickbat on 30 August 2007, 22:09:55
As others have said, I reckon the crank sensor is the most likely culprit. Around £34 (see other thread http://www.omegaowners.com/forum/YaBB.pl?num=1188504203) and relatively easy to fit. It's worth doing in any event because, even if it hasn't gone, it is likely to do so in the not-to-distant future (especially given the mileage).
Title: Re: 2.5 V6 won't run
Post by: TheBoy on 31 August 2007, 10:24:38
AndyT - can you update profile with location? Are you near me?
Title: Re: 2.5 V6 won't run
Post by: AndyT on 31 August 2007, 12:35:19
My location is Essex - too far away from you unfortunately.
The crankshaft sensor theory makes sense so tomorrow I intend to remove it to see which one it is (seems there are 2 or 3 varieties) and then I will order one up from one of the websites and give it a try.
I will post the result.
Andy T
Title: Re: 2.5 V6 won't run
Post by: Nickbat on 31 August 2007, 12:52:55
Andy, you don't need to take off the whole thing to tell which one it is. Disconnect the top end of the cable and take a look. Some have a square connector, some have a slightly oval connector. If you want you can take a photo and post it here and someone will identify it.

Good luck!  :y
Title: Re: 2.5 V6 won't run
Post by: AndyT on 31 August 2007, 19:56:25
 ;D ! ! FIXED IT ! !  :)

I am almost embarrassed to admit what the problem was ! One of the air ducts from the multiram to the throttle body had partially slipped off at the multiram. Not easy to see unless you are looking really hard. Put it on again (firmly) and it started straight off. Whilst it was running, I removed the duct again and the engine stopped immediately.
So many thanks to all of you out there for your assistance and suggestions - its great to know that when problems do occur there are people who are willing to help.

Andy T

Oh - and thanks to Mr Haynes who in his manual suggests that you look for air leaks if you have this same problem. First time ever in my experience he has been right.
Title: Re: 2.5 V6 won't run
Post by: ians on 31 August 2007, 23:29:03
 :y :y
Title: Re: 2.5 V6 won't run
Post by: Nickbat on 31 August 2007, 23:42:29
 :y :y

Cheaper than a crank sensor!  :y