Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: SingleCylinder on 05 August 2007, 18:10:57
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Any help or suggestions to a slightly aged newcomer would be gratefully received:
I have a low mileage (15K, one family hand-me down) Feb 95 2.5 CDX automatic saloon that has recently started an intermittent "total" misfire - for want of a better description - but only when the engine has been running for a while. The car is only used for the occasional longer journey. This intermittent fault occurs when accelerating from a standstill (really juddering), or when driving at about 45-60 mph ("finer" rapid juddering). When it occurs, the instantaneous consumption shoots up to about 7mpg, but a quick blip or easing of the accelerator immediately cures the problem, only for it to come back a few seconds or often minutes later.... Possibly strangely, no problems whatsoever above about 60mph - in fact very good performance and consumption - or when gently pottering about.
The plugs are brand new, their leads about a year old, new air and fuel filter. No oil appears to be leaking from the cam cover gaskets into the spark plug recesses - or anywhere else. The ATF was changed about two weeks ago by a local automatic transmission firm. The water pump was changed a few weeks before this problem begun. There are no obvious signs of engine overheating and the heater certainly works. However, there seems to be bit more heat coming from under the car after a longer run - noticeable when getting out of the driver's door.
The car has just come back from a trip to France where I had to put in about 50 litres of a "generic" fuel (not Total or other well-known petrol), which seemed to make the problem more frequent. Filling up on return with Shell 98 octane fuel (an old and expensive trick that doesn't seem to works so well these days!) seems to have made only a slight improvement. The hairclip ECU test only returns codes 145 and 144, in that order: related to the immobiliser circuit?
Probably missing something obvious (faulty or bad contact crank sensor, etc), but the clearing up - if only temporarily - of the problem each and EVERY time by the slight blip or release of the accelerator is throwing me at the moment!
With thanks for reading this, Single Cylinder
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Check for fault codes (paperclip test), if none, suspect HT (as you've changed plugs and leads, that leaves DIS)
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Does sound like DIS pack.
£70 for Bosch part on Ebay, more like £100 trade from Vx.
Quite fiddly to replace.