Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: katiecuppa on 29 September 2009, 17:50:01

Title: Hot running problem
Post by: katiecuppa on 29 September 2009, 17:50:01

Hi everyone, I need your help. When my '97 2.5 v6 estate starts it runs fine but when it gets up to around 90 temp, (after around 20 mins driving) it starts to kangaroo and dies. I have also noticed that the temp guage then drops to 0 and the rev counter jumps up and down. Then engine will restart after cooling  but I am afraid to drive for any distance. I have changed cam and crank sensors, new HT leads. The codes from paper clip test are 12 and 31 when off and 12,12,12 etc when running.
Any ideas as I want to drive the bloody thing.
Many thanks :y

Title: Re: Hot running problem
Post by: RobG on 29 September 2009, 20:14:43

Classic crank sensor symptons. Did you use genuine and did you re-route the cable  :question

Title: Re: Hot running problem
Post by: katiecuppa on 29 September 2009, 22:47:05

It's a genuine sensor but I didn't re-route.
However, I did the paperclip test after I got the juddering and I got 12 and 31 with ignition on, and just 12 with engine running.
When the old non-genuine sensor was on the car, I got 19,73 and 74.
Could it be a dodgy alternator or a bad earth? Where are the earth points located?
Would the erratic rev counter be anything to do with this? 

Title: Re: Hot running problem
Post by: jonnycool on 29 September 2009, 22:56:11

Yes, could be the crank sensor if you didn't route the new one away from heat sources such as oil cooler pipes and exhaust pipes. My original crank sensor used to suffer from heat-related problems, would run all day when hot but as soon as you turned the engine off, it wouldn't start again until it was completely cold!
  It's certainly a job to rule out first  :y :y Hope you get it running soon

Title: Re: Hot running problem
Post by: iainb on 29 September 2009, 23:00:02

Code 74 is the maf sensor and when it plays up the engine over fuels.
Disconnect the maf sensor and spray some contact cleaner onto the terminals.
Allow to dry and then reconnect the connector.

Title: Re: Hot running problem
Post by: katiecuppa on 29 September 2009, 23:12:59

The last paperclip test I did, I got 12 and 31 ignition on and just 12 with engine running which suggest no faults to me.

Title: Re: Hot running problem
Post by: JasonH on 30 September 2009, 13:05:10

I think you've got a heat related electrical connection issue, like a loose connection on the battery. Or perhaps a short on the fan wiring - when the fan cuts in the engine cuts out!

For the temperature gauge to drop the 12V must be being disconnected.

Crank sensor codes seem fine, they're not always reliable but if you've replaced the sensor I'd rule that out for now.