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[steve6367]

A concise summary - running very rough when first start, now cold, or warm - if hot it runs ok. Under very hard acceleration (up hill when moving fast) it hesitates somewhat. P1130, P0136 and P0170 being logged regularly.

So far I have checked induction and exhaust, changed lambda sensors for known good, same for CAM sensor, stripped breathers and throttle body and cleaned, checked timing, changed plugs, coil pack and fuel and air filter. I just seems to be getting slowly worse and worse.

I feel like I may have to admit defeat, but thought I would ask here once more :-) (the V6 seems to have developed and spectacular cam cover oil leak with smoke etc so could really do with this one working while I fix that!)

Many thanks in advance.

Steve


Background here: http://www.omegaowners.com/forum/index.php?topic=123467.msg1572068#msg1572068

[tunnie]

Tried unplugging the MAF sensor?

Is it loosing coolant?

[steve6367]

Tried unplugging the MAF sensor? - Yes it did not make a noticeable difference other than the appropriate code logged.

Is it loosing coolant? - Not that I can see not put any in since HG change and level looks ok.

I have also checked all 4 cylinders for water after standing over night, so hope its not HG again!

[Sp4rkst4rt3r]

I had an emissions failure last month, after doing everything you have mentioned I decided it needed to go to a 'Specialist'.
It transpired that it was a bad ground to the first 02 (Lambda) Sensor which I would never have found.
A temporary earth (Ground) was spliced into the Sensors wiring and it flew through it's Emissions test.

Basically I was getting a 0170 coded fault which pointed towards the 02 Sensor.
0170 - Fuel trim Bank 1.
Then after cleaning and swapping bits it developed into '02 Sensor Circuit Fault' (Can't remember exact wording or code).
I must have damaged the wiring loom during my cleaning phase.

I experienced the same as you described (loss of power if anything more than 50% throttle) but only got 0170 code on it's own.
It also had a very slight 'Miss-fire' which wasn't a miss-fire but unspent fuel burning in the exhaust due to ECU running engine rich to compensate for the 02 Sensor not being active (broken earth).

I have also had issues with power and starting when my Fuel pump started to fail. This was also linked to a failing Fuel pressure regulator (located on fuel rail).
What was happening was the pump couldn't supply enough fuel beyond 50% throttle and there was only 2.4 Bar at the rail.
I believe the 2.2l 16v requires a minimum of 3.0 Bar of pressure.

Now the pressure regulator has a small pipe running to the throttle body which creates a vacuum for the regulator which could also create a fueling issue if it has become faulty (i.e. Taking too much pressure from the fuel rail).

Obviously both the pump and the regulator work in unison so it is necessary for both to be working correctly.

May I suggest a pressure test on your fuel rail and a full diagnostics being done.
This cost me £75.00 inc VAT to find the problem which I would never have found myself.

Hope this helps 

[steve6367]

I think the Lambda wiring is ok as they look good in live data.

Not thought about fuel pressure though - wonder if I can test? Or is that a garage only job?

Steve

[05omegav6]

You could swap the pressure regulator from the 2.5 to test it, and swap the pump as well

For the pump you need to remove and dismantle the cage, see Haynes, and I am assuming that although the cages are different saloon/estate, the pumps are the same...

[Sp4rkst4rt3r]

For the pump you need to remove and dismantle the cage, see Haynes, and I am assuming that although the cages are different saloon/estate, the pumps are the same...

You are correct with that assumption in so far as I had a 52 plate 2.2l 16v saloon and I fitted the pump into my 2001 estate.

The pump is basically held in place by three tabs, once the tabs are pressed inwards the pump releases and lifts upwards away from the 'Cage'.

It is a very simple operation but is obviously fraught with danger as you have an opening of about 6" into the fuel tank once the top is removed.

Please ensure you do this job in a well ventilated area and have a fire extinguisher to hand or at least a bucket of sand.

[steve6367]

Sounds good, I had no idea the 2 engines used the same units 

Will I need to get the fuel trims reset? (they have drifted way out now) or will they come back into line once the fault is fixed?

Many thanks

Steve

[05omegav6]

They should self learn, but if you leave the ecu unplugged overnight then that should reset them

[Sp4rkst4rt3r]

They should self learn, but if you leave the ecu unplugged overnight then that should reset them

I didn't know that, I thought the ECU would auto-correct itself 

I'll give that a try tonight when I get back from work 

Cheers Al you are a star 

[steve6367]

Disappointingly leaving the battery over night does not seem to have touched the long term fuel trim stored value. Was off for 10 hours, is that long enough?

Steve

[steve6367]

Did anyone know about 2.2 fuel trims? Is Tech2 the only was to reset?

Steve