Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: JohnM on 07 December 2019, 20:30:14
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Restoring the 'misfire' project: (I needed it all off again - original post to be updated in due course).
Can anyone confirm by wire colour codes which 2-pin connector is which ? (IAC / Rear multiram)
- old 'un, pre-facelift, S 98?
With 'further work' it is possible that the IACV plug and the rear multi-ram plug may have become swapped.
Both have the same plug, both have orange plaggy bit inside and come from the cable tray (all been out).
I did wonder as I put it together again (the first time back it was correct) but there is no way to identify one from the other; the cable that looks like it should run the the IAC motor is plugged there.
I can only think to identify by the colours of the wires; but I only have haynes for a diagram (I found it!) and it isn't helping much as Y15 solenoid secondary air intake (295 BN,VI) is showing in different places, I think the IAC is M33 - yet to be located.
The wiring colouring is old, dirty and hard to verify but I'm hoping to be able to distinguish A from B if anyone has a better source. Neither look to have one brown and one violet to me.
Symptoms: started up with 1.5-2k revs for say 5 seconds, then dropped back to idle but died. Restarted but unhappy (cold). No EML when running.
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An "S" 98 would be a mid facelift car I believe.According to my Haynes under "later cars" the IACV is M66 which has red/white and red/blue wires.Y15 has red/white and brown/grey wiring.HTH.
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As I recall, the cable that connects to IACV has a circular black corrugated plastic sleeve tube behind the connector, the intent being to protect the part of the cable that's outside the tray. The distal end of the tube has a circular molding that sits in a cutout slot in the top of the cable tray, whre the cable exits. The orange 'plaggy' bit is a seal to 'weatherproof' the connector.
On the other hand the exposed end cable for the rear multiram might be protected with heat-shrink or maybe a black fabric tape wrap. So it looks different.
Might be that I have that completely wrong or that the corrugated sleeve and/or the heatshink/wrap has been lost over the years. Or maybe a MFL is different to the earlier cars.
However disconnecting either connector should trigger a fault code. So if they were the wrong way round you should have codes for both. If not, perhaps try disconnecting the multiram and try to start the engine. See what code gets stored?
Also I suppose you could also try introducing a vacuum leak and see what that does to the idle.
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SOLVED.
Thanks Baza; not sure about mine being a "mid-facelift" car, not a term I've come across. My IACV looks to be orange (red/white morphed?) with brown/blue (could indeed be red(aged)/blue).
Enceladus, taa also; you're right(ish), that sleeving (copex style) is what I was going on, but both mine have some and both are/were wrapped also (further up/down). I'd over-taped some fabric wrap as it is falling apart and second go around the other connector warranted some over taping (that, I think is where any mix-up may have happend). Note to self: blue tape is rear multi-ram!
All sorted now. I had a think last night (as you do) as I wasn't convinced there was a mix up (but who builds these with two plugs the same in reach - all others are either non-interchangable or are colour coded different inside). Thought about how it started (rather like with an air leak) and what I'd done to (possibly) mix up the cables. Not sure, but I was when I looked!
There is something in the way (when back together) stopping you checking the rear multi-ram cable - the vac tak-off.
I'd removed it again for access and parked it towards the cabin filter hole.
No IACV cable connected doesn't bring up an EML on it's own, but the engine correctly dies after start-up (I can't think how I know that!).
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So are all your issues now solved? Or not?
You started with a misfire and that sounds like it was rectified by replacing the coil pack by a pukka Bosch unit. Is that correct?
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Yes, misfire sorted (by a new coil pack - having cleared water (mainly) out of #3 well).
Proof in the longer term (I need to sort out the aux tensioner and sealing/windscreen replacement before using the car.
- I did update the misfire post but the title change/s (update) don't seem to stick/be visible.