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[Diamond Black Geezer]

Slight, slight lumpiness to my girl. Noticeable at idle, at what appears to be a steady indicated 500rpm, you can just feel a little bumping in the driver's seat, and a little vibration through the steering wheel. For completeness I'll mention this morning, and also one other time, last week the revs spiked at maybe 750 for literally a split second.

This weekend I'm on with plugs, all filters and oil, see if that alters anything.

HTs are brand new, DIS is decent.

If you add a couple more revs she smooths out, but when you look in the engine bay I still think she rocks a little on her engine mounts, I may be being very pedantic on this, however. Have a couple of spare ICVs which I'll swap over just to eliminate that, though can't see it myself.

Just wondering if the crank sensors can start like this, with a very tiny, tiny level of roughness? Can't think of anything else off the top of my head to cause this, that's all. 

Thoughts appreciated 

[Steve B]

Same here on my 3.2. Tickover a little lumpy..Feel it in the seat and when you open the bonnet you can see you have a uneven tickover
Its a case of checking for Vac/Air leaks.

 It is said on here that it is down to the ECU constantly adjusting the Fuel/Mixture setting to obtain a even tick over,And i do believe it is said that the 3.2 does not have a great/even tickover,,If so ? what was it like when it was new 

[zirk]

Codes?

[Diamond Black Geezer]

Will try and get codes soon as I can, tonight/tomorrow night. Annoying as basically all the vac pipes were done a matter of weeks ago, of course it only take a teensy-weeny one to cause issues. Will get investigating the vac side of things 

[Steve B]

Dont think you will have codes 

[zirk]

Dont think you will have codes 

Probably not, but always a good place to start, especially on our own cars as we sometimes go off course a bit thinking we know how it should and shouldn't run.

[Diamond Black Geezer]

The other thing is I'll have lots of lovely codes - many of which will be 'old' info, they've certainly not been cleared any time in the last decade  But will check both codes and for air leaks best I can 

[Mr.OmegaMan]

"Slight, slight lumpiness to my girl. Noticeable at idle, at what appears to be a steady indicated 500rpm, you can just feel a little bumping in the driver's seat"

Had this happen last night (for the first time oddly enough, maybe something in the air) but its fine today.

Popped the Autel AL519 on earlier and there where 2 pending codes (P0150 O2 Sensor circuit bank 2 / P0173 Fuel Trim Bank 2)

Cleared them will just have to see if they return or not, For now anyway the engine is back to normal... Something new everyday the joys of Omega ownership.

[Webby the Bear]

Vac leaks DBG as said before 

Check top hat seal breather bridge to plenum and bridge to TB o rings. for a confirmation (although TheBoy will kick my arse) spray carb cleaner round that area with car running.

check vac lines: their quality and check against marks guide for vac pipe layout.

check brake servo pipe.

and for completion pull top pipe off front vacuum box and right hand side one on rear vacuum box (found it yesterday  ) they should ''hiss''. if not replace vac box.

 

[Diamond Black Geezer]

Cheers chaps!

Will hopefully get chance to have a look tonight 

Thanks Webby for your detailed instructions, too.


Just glad that I haven't the start of crank sensor issues!

[05omegav6]

2.6/3.2 have a relatively unsettled idle, electronically induced, as the ecu fine tunes the fuelling/throttle position

2.5/3.0 idle far more steadily as the ICV is generally held in a stable position... being a much smaller bore than the throttle intakes, it is a much more delicate device when compared to the dbw throttle actuator

[Diamond Black Geezer]

I was sure it wasn't in my head that she idled better a few weeks ago, glad to see they should be sewing-machine-like.

I have actually fitted a little (GM) clip on the main vac hose to plenum - to hold the AC pipe from chafing. As it was a tight fit (maybe the aircon pipes have been bent at some point in time) maybe this is straining the vac hose, and causing a little weep of air... maybe. As it's the only thing that's actually 'changed' in the engine bay I'll check that also.

[Marks DTM Calib]

"Slight, slight lumpiness to my girl. Noticeable at idle, at what appears to be a steady indicated 500rpm, you can just feel a little bumping in the driver's seat"

Had this happen last night (for the first time oddly enough, maybe something in the air) but its fine today.

Popped the Autel AL519 on earlier and there where 2 pending codes (P0150 O2 Sensor circuit bank 2 / P0173 Fuel Trim Bank 2)

Cleared them will just have to see if they return or not, For now anyway the engine is back to normal... Something new everyday the joys of Omega ownership.

Block learns (fuel trims) have drifted out for some reason, the reset will have rest them so expect it to return shortly as they drift out again.

[Mr.OmegaMan]

"Slight, slight lumpiness to my girl. Noticeable at idle, at what appears to be a steady indicated 500rpm, you can just feel a little bumping in the driver's seat"

Had this happen last night (for the first time oddly enough, maybe something in the air) but its fine today.

Popped the Autel AL519 on earlier and there where 2 pending codes (P0150 O2 Sensor circuit bank 2 / P0173 Fuel Trim Bank 2)

Cleared them will just have to see if they return or not, For now anyway the engine is back to normal... Something new everyday the joys of Omega ownership.

Block learns (fuel trims) have drifted out for some reason, the reset will have rest them so expect it to return shortly as they drift out again.

Yeah have had these codes pop up now and then for 2 or so years only that night it acted up a little while idling (might not have been related to these codes even), Changed the MAF for a known good one, Live data seems to suggest the O2 sensors are working, No vacuum leaks that i could find so never bothered looking into it any further seen as it ran fine and still does, Only other thing i did that night was top the oil up after seeing that low message, But don't see why that would have caused an issue with the idle unless i put a tad too much perhaps but doubtful though, Only put in say half a mug of 10/40 GM. 

[Diamond Black Geezer]

Vac leaks DBG as said before 

Check top hat seal breather bridge to plenum and bridge to TB o rings. for a confirmation (although TheBoy will kick my arse) spray carb cleaner round that area with car running.

check vac lines: their quality and check against marks guide for vac pipe layout.

check brake servo pipe.

and for completion pull top pipe off front vacuum box and right hand side one on rear vacuum box (found it yesterday  ) they should ''hiss''. if not replace vac box.

 

1 not checked yet

2 Plumbing as per Mr DTM, spot on

3 Brake servo pipe spot on

4 not checked yet


Pulled off each thin pipe off the main servo pipe and blocked the fresh hole in the servo pipe with thumb to check for alteration in the idle. Going to analyse the vac boxes next, hoping it's one of them. 

Thanks, report back tomorrow!