Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[aaronjb]

It can be done via the knock sensor too, and by looking at acceleration of the crank around the ignition event. I don't know how the system on the Omega works, but I know it will detect cylinders that misfire due to lack of fuel, so it's not purely based on whether the spark was generated.

You know I'd never thought of doing it that way.. I suppose the knock sensor would see 'quiet' during a non-ignition event, and the crank acceleration wouldn't be as high (although that's damped by harmonic dampers on a lot of engines - I don't know about the 2.2 on the Omega, mind.. does it have a rubber ring in the crank pulley?).

Interesting.. thanks - you learn something new every day, as they say

[Kevin Wood]

You know I'd never thought of doing it that way.. I suppose the knock sensor would see 'quiet' during a non-ignition event, and the crank acceleration wouldn't be as high (although that's damped by harmonic dampers on a lot of engines - I don't know about the 2.2 on the Omega, mind.. does it have a rubber ring in the crank pulley?).

Interesting.. thanks - you learn something new every day, as they say

Not sure about the 2.2 but on the V6 the reluctor for the crank sensor is on the crank itself, so no damping there. I imagine the 2.2 is the same, based on the sensor location.

All depends how intelligent the ecu is. There was a time when they had very limited processing power so very little diagnostics could be built in. Knock sensor triggers were analogue, for example, so you couldn't tell the difference between knock, normal ignition and no ignition.

Nowadays you can cheaply build in very precise timing and analysis of waveforms coming from the sensors.

In fact, knock sensors themselves are probably on their way out: http://delphi.com/manufacturers/auto/powertrain/gas/ignsys/ionized/

This type of technology allows you to measure where in the engine cycle the "peak pressure" is occurring, and the ignition timing can then be adjusted to get the best from whatever fuel you are using.

aaanyway, back to the 2.2 Omega.

Kevin

[Dom]

Hi all, thanks for your help so far.

I have confirmed that there is no spark to number one. I did this by taking out the coil pack with the spark plugs in, earthing them to the battery with jump leads and turning the engine over. Sparks from the rest but not number one. I had wondered about the cam sensor as it seem ls resonabky easy to get too.

Glad to hear that it will cut the fuel too as a was concerned I would be wrecking the cat. Although I seem to recall the plug being wet? That could have been when the fault was intermitant though. It is now more or less a perminant feature!

When CAM sensors fail do they tend to fail gradually as per the fault I have?

Also, what's the Knock Sensor?

[Kevin Wood]

Hmm. Puzzling. Are you absolutely positive that the coil pack is good and the connections to the coil pack primaries from the ECU are sound?

The P303 code you had is related to cylinder 3 - so has it moved to cylinder 1? If so, what component change caused that? I wonder if you have 2 faulty coil packs, with a different pot misbehaving on each?

A crank/cam sensor issue would not affect a single cylinder, IMHO.

Kevin

[mathewst]

Cam sensor will fail gradually on 2.2. at least from my experience. I have a troublesome one and it it still works. Causes a problem once in every two months and even then after a restart works normally

[vauxhallvauxhall]

this is probably not the cause but this has happened to me on a ford with identical intermittent fault wire in  injector plug on affected cylinder was slightly pulled into the plug caused by pulling the wires when removing

[Dom]

Firstly a big thanks to Welung666 for taking the time to come over a take a look at my omega. Top man! Turned out to be the coilpack at fault! Very frustrating as this was one of the first items I changed months ago. It does expain why the missfire changed from pot 3 to pot 1 I just never made the connection that it happened after changing the pack. I feel a bit daft having spent months trying to resolve the issue. Learnt a lesson about not just assuming a repacement part will work even if sold as a good one from a Vauxhall specialist breakers though! I still need a coilpack as the one I tested it with was from my uncles car. If anyone has one for a 2.2 let me know. I also have a known good spare ecu which will be heading for eBay!

Thanks to everyone for your help I am looking forwards to driving on 4 cylinders again!

[Welung666]

Just got home and having a nice cold, ice cold can of 'wind down' Very nice to meet you Dom, you'd already done a fair bit of work trying to narrow it down, mostly misleading unfortunately thanks to some of the bad advice given on 'the forum we can't mention'. Still, we got there