Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: terry paget on 06 December 2014, 07:51:56
-
My favourite Omega, the 2.5 petrol CDX, X reg, mileage 153162, bought from OOF member ajsphead in March 2014, has developed a misfire under extreme load, i.e. full throttle 20mph in 4th gear. No EML on.
Service records show plug change Feb 2013 140000 miles.crank sensor at 144K. e-bay advert stated 'the breathers and plenum have been cleaned at 140K and all the belts etc. done at 133K. the cam cover gaskets are fine too. I've never had a problem with the coil packs'.
Last week I posted my suspicion of leaking scuttle. I have since sealed it, anyway it was dry last night.
Oil/water in plug holes? Plug leads? Coil pack? My money is on coil pack, but I would welcome expert advice.
-
Have you checked the codes?
If no codes suspect missfire. Which means checking all you listed.
Full throttle in 4the gear though :-\ .... Are you sure it's not stalling?
Coil pacs some times split if nothing else is visible. But that usually means the missfire affects pairs of cylinders and the car sounds like a Subaru flat four.
....full throttle in fourth.... Wow. I presume it's a manual?
-
paper clip codes: 1 2 1 2 1 2 1 9 1 9 1 9 1 2 1 2 1 2 1 9 1 9 1 9 ignition on engine not running Not OBD2 so code reader no help. What does that mean?
-
Crank sensor, according to that.
-
Thanks! That's easy to change. I assume it will be a Siemens, in which case I have a spare. I will change that first.
-
Miss under load almost always HT related and won't log a code :y
-
Sensor locating screw was loose. Am having difficullty disconnecting the connector, may have to remove either plenum or scuttle. I wouldn't like to do it at the roadside.
Could the loose screw cause my problem?
-
It could create an intermittent earth fault as the sensor rattles around :-\
Probably not very good for the sensor either...
-
I have reassembled, with crank sensor screw tight. I shall find out next Friday if fault is cured or not. Will report back.
Thanks. My feeling was if I change the crank sensor for good spare and fault has gone, it could have been either sensor or loose screw. Either way I would have discarded original sensor, which might be OK.
-
Why not test run the car before Friday when it's needed?
-
Fair question. This is the same car which the previous Friday caused me to post the thread 'scuttle leaks causing misfires'. It only misbehaves after a 60 miles thrash along the A34 and M4 late on a Friday night. First I thought it was leaky scuttle; then I thought it was failing coil pack; now thanks to your advice on codes I think it is crank sensor or loose crank sensor. To test I need a 60 mile thrash; I shall get one on Friday.
I love these seasonal emoticons! ::) ::) :P :y
-
Misfire is still there! Driving hoe form Wells tonight, 10 mile journey, it again misfired under full throttle at 20mph. So it was not the loose crank sensor. It did not do it when it was cold, but after 10 miles it did. Sounds like crank sensor, doesn't it? And code 19.
Sunday I found it difficult to reach the crank sensor lead connector without removing scuttle or plenum. Al tipped me I could change plugs on left hand bank if I first unscrewed the vacuum pipe to servo, then unplugged the rear dual ram plug, unscrewed the harness locating screws and popped the harness box on top of the vacuum pipe. I could not see how to unplug the dual ram plug, Al. I would need long strong fingers. Is there a trick?
-
I squeeze the spring clip together and wriggle the plug off... :-\
Are we still talking the 2.5 though? no need to disturb anything to pull the leads off and unscrew the plugs, surely...
Just because the scuttle is sealed, doesn't mean the DIS pack isn't gradually failing... the fact it only does it when hot, suggests that summat is expanding... ie the coils in the dis pack...:y
-
Is code 19 still there?
-
I squeeze the spring clip together and wriggle the plug off... :-\
Are we still talking the 2.5 though? no need to disturb anything to pull the leads off and unscrew the plugs, surely...
Just because the scuttle is sealed, doesn't mean the DIS pack isn't gradually failing... the fact it only does it when hot, suggests that summat is expanding... ie the coils in the dis pack...:y
Yes, we are talking 2.5. I cannot get access to the plugs without moving the wiring harness. You said recently procedure wsa as to unscrew the vacuum pipe, harness locating screws, unplug rear dual plug, then prop the harness on the vacuum pipe and then remove plug leads and plugs. You say I can put a hand through to the dual ram plug, squeeze the spring clips and wriggle it off. I have always found it hard to remove in the past, usually doing it after I have lifted the plenum off the manifold.
I agree fault may be coil pack. It still could be water/oil in plug holes or plug leads. It wsa code 19 that suggested crank sensor. Engine has never stopped, it just misfires under heavy load, when hot.
-
Is code 19 still there?
I don't know. I will check in the morning.
-
Ah ok... only need to unscrew the wiring tray on that... the rest is DBW only to clear space to remove the coil pack :y
The wiring tray should suffice on the earlier V6. Failing Crank Sensor would cause stalling rather than misfiring, plugs, dis pack and the leads, in that order, are the three likely candidates.
My money is on the dis pack fwiw :-\
-
Is code 19 still there?
New codes. 1 2 1 2 1 2 7 4 7 4 7 4 3 1 3 1 3 1 then repeats.
-
Ah ok... only need to unscrew the wiring tray on that... the rest is DBW only to clear space to remove the coil pack :y
The wiring tray should suffice on the earlier V6. Failing Crank Sensor would cause stalling rather than misfiring, plugs, dis pack and the leads, in that order, are the three likely candidates.
My money is on the dis pack fwiw :-\
My money is on dispack too, but I have posted more codes; 19 has gone! Now I have 74 and 31. Are they any help?
-
74 is MAF and 31 simply means you forgot to turn the engine on when you checked the codes :P ie no RPM signal :y
-
It may have more than one fault. 2.5 3.0 do not record miss fires.
Is code 19 still there?
-
It may have more than one fault. 2.5 3.0 do not record miss fires.
Is code 19 still there?
No, 19 is gone, now I have 74 and 31.
-
74 is MAF and 31 simply means you forgot to turn the engine on when you checked the codes :P ie no RPM signal :y
Thanks. MAF, eh? I must have a spare MAF somehere, and it's easily changed. As mentioned before, I bought this car for spares, but when I found it was so good I kept it and scrapped the other 2.5 estate. I must have all the useful bits somewhere, including the MAF.
-
Un plug it to see if it improves matters :y
-
It may have more than one fault. 2.5 3.0 do not record miss fires.
Is code 19 still there?
No, 19 is gone, now I have 74 and 31.
Ok good. 31 normal with engine off.
Maf is farely reliable on the pre face lift, so I'd get some live data before condemning that.
-
Thanks for your help, lads, I have found all the bits off the car I scrapped. I have swopped MAF sensors, engine still runs, but I doubt that will cure it. I found all the plugs, plug leads, and coil pack in a bag, labelled. I shall test the car Friday, and if not cured I shall change the lot. I will report back.
-
Intend to change plugs, leads and dispack. Am dismantling, have changed plugs and removed leads 2, 4 and 6. Leads 1,3 & 5 trapped somehow, and am strugging to remove dispack bolts. Lead no. 6 came off in 2 bits. I did not pull it very hard, honest. Might this be the problem? I drove this car 200 miles yesterday.
Pic of lead follows.
https://www.dropbox.com/s/uvrsqejwsh4cozx/PLUGlead40%25.jpg?dl=0 (https://www.dropbox.com/s/uvrsqejwsh4cozx/PLUGlead40%25.jpg?dl=0)
-
Might this be the problem?
https://www.dropbox.com/s/vjj0j00o0dfukgb/coilpack40%25.jpg?dl=0 (https://www.dropbox.com/s/vjj0j00o0dfukgb/coilpack40%25.jpg?dl=0)
-
Might this be the problem?
https://www.dropbox.com/s/vjj0j00o0dfukgb/coilpack40%25.jpg?dl=0 (https://www.dropbox.com/s/vjj0j00o0dfukgb/coilpack40%25.jpg?dl=0)
Aye, that be it :y
-
I have a new problem. There is a broken cable end, middle of picture attached, going vertically down and under the dispack tray. In the cable are two wires, one with white insulation. I cannot pull it up far. I cannot find the other end of it. I have no idea of its function, or how long it has been there.
Has anyone any suggestions?
https://www.dropbox.com/s/oqbfy03iui22snm/looseWIRE40%25.jpg?dl=0 (https://www.dropbox.com/s/oqbfy03iui22snm/looseWIRE40%25.jpg?dl=0)
-
Not certain, but could be a crank sensor cable ??
Not unknown to simply chop the ends of the original cable when replacing the crank sensor as the routing is not "easy" and the suggested "new" routing in the guide is far cooler for the wire.
-
It could indeed. I agree, that is here the original crank sensor cable would have gone, bundled with the oil pipes. The car is fitted with a replacement crank sensor, with the cable coming up attached to the brake pipes to the ABS unit. Phew! That's a relief. So I can ignore it. Many thanks.
-
I changed a DISpack on my Opel 2.5 a year ago. My photo show the case split in the same place (end opposite to the connector) as that in message 27. The example in the maintenance guide is also split in the same place.
That is beneath the join in the scuttle. I reckon the cause is water dripping on to the coil pack there, causing shorting of sparks, cracking the casing, then getting inside and allowing rusting, bursting the case, and failure. Moral is, always reseal the join after disturbing the scuttle.