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[tommy mac]

Hi everyone,

I'm new to the group but have been exploring the site in some detail as an owner of a 52 plate 2.2cd auto.  The car has recently covered 100,000 miles and a few weeks ago James (The Omegamechanic ) fitted a new cambelt and gear selector switch for me.  What a find James is, and such a knowledgeable chap!

Last week the car failed its MOT on the emissions and the garage identified the problem as the lambda sensor (the error code P0107 kept appearing).  I changed the sensor and the error code went away but the car has not been running well.  On a long run it was clear that acceleration was fine but there was a noticeable hesitancy when cruising at a steady speed.  James pointed out that the cam cover was leaking (oil in the plug wells) so I decided to change the gasket and clean all the breather pipes.  I did this and aqalso removed and cleaned the throttle valve assembly, replacing it with a new gasket.   After this the car started very well indeed but had a hint of rough running when idling.  A short drive was not reassuring as the car accelerated well but is even more hesitant than before and struggling to run at a steady speed.  A check of the error codes showed only one that related to not enough torque from the engine.    After another check to ensure I had not missed any poor connections or loose pipes I started the engine again and despite an easy start it seems to be running rougher than ever.  Going through all the posts of similar issues on here isn't helping me with this problem.  I have checked and double checked the electrical connections, and made sure all the pipes are connected properly but the problem seems to be getting worse.     

My thoughts are that the fact it is starting well suggests that the ignition system is probably ok, and based on anexperience with a previous car (30 years ago!) the symptoms could suggest fuel starvation.  Could it be linked to the MOT emissions failure - could it be the mass air flow meter?

I am so aware of how easy it is to chase my own tail when tracking down the cause of such problems so any ideas would be of help.

[TheBoy]

Are the long term trims around 0% (assuming your code reader can read it)?

Any stored codes?

[tommy mac]

Sorry I can't read the trims on my reader and there are no stored codes......the P0107  was the only code that has come up (other than the recent low torque message which I assume was due to the power issue giving the gearbox a problem) and that vanished with the new lamda sensor.

Tom

[Entwood]

If you can get to Wootton Bassett tomorrow I should be able to read the trims for you ??

[TheBoy]

If you can get to Wootton Bassett tomorrow I should be able to read the trims for you ??

If you 2 can get together, can you get:

Codes
Trims
MAF
Confirm that S1 flicks at about 1hz, S2 is always lean

Might be worth checking condition of coil pack - easy on 4 pot, slide the trim back, unplug CP at rear, unbolt and lift as per a V6 one.

[dbug]

If you can get to Wootton Bassett tomorrow I should be able to read the trims for you ??

If you 2 can get together, can you get:

Codes
Trims
MAF
Confirm that S1 flicks at about 1hz, S2 is always lean

Might be worth checking condition of coil pack - easy on 4 pot, slide the trim back, unplug CP at rear, unbolt and lift as per a V6 one.

Thats my guess 

[car5car]

I had O2 sensor codes, but problem was MAF sensor. Disconnect MAF, if car runs better, it is bad. Very often computer doesn't recognize bad MAF sensor, because signal is within specs.

[2woody]

did you change the right lambda sensor ?

[tommy mac]

Wow- such fast responses.   Thanks to all.   Going in reverse order The lambda sensor changed was the front one and it certainly got rid of the error code. Whether it was the correct one I can't answer.  I did try running the car with the MAF sensor disconnected with no better results and probably slightly worse.   The coil pack did have oil coating the plug connectors and these have been cleaned thoroughly.  I am aware that they can fail after an oil 'bath' - the low power and unsteady running could indicate an ignition problem  but i don't hear any hint of misfiring.  Oh to have a spare car to swap parts with. 

Entwood, I can attempt a trip to Royal Wootton Bassett - is anytime in particular good for you?  In the meantime I'm going over the engine with fresh pair of eyes to be doubly sure I have not done something stupid in my cleaning!

Tom

[Entwood]

Wow- such fast responses.   Thanks to all.   Going in reverse order The lambda sensor changed was the front one and it certainly got rid of the error code. Whether it was the correct one I can't answer.  I did try running the car with the MAF sensor disconnected with no better results and probably slightly worse.   The coil pack did have oil coating the plug connectors and these have been cleaned thoroughly.  I am aware that they can fail after an oil 'bath' - the low power and unsteady running could indicate an ignition problem  but i don't hear any hint of misfiring.  Oh to have a spare car to swap parts with. 

Entwood, I can attempt a trip to Royal Wootton Bassett - is anytime in particular good for you?  In the meantime I'm going over the engine with fresh pair of eyes to be doubly sure I have not done something stupid in my cleaning!

Tom

PM sent with phone number ..

[TheBoy]

I had O2 sensor codes, but problem was MAF sensor. Disconnect MAF, if car runs better, it is bad. Very often computer doesn't recognize bad MAF sensor, because signal is within specs.

Reading codes alone is a poor way to do diagnosis, hence in this case the request for live data.

Disconnecting MAF can help in diagnostics if no other tools available, but that still cannot pin it down to MAF (in cases where MAF is correct, but other sensors are incorrect)

Hope that makes sense?

[Entwood]

Quick and dirty, accurate stuff to follow...

S1 not changing,


Sht trim 0.0 not changing

Lng trim 11.7% not changing ..

Off to write some info down .. back shortly

[Entwood]

Right accurate info

Closed Loop
SHRTFT1 - 0.0% - not changing
LONGFT1 - 11.7% - not changing
RPM - 762
ADV - 4-6 degrees, varying slowly
MAF 2.53 g/s
TP 3.1%

O2B1S1  0.075  STATIC over 5 minutes
O2B1S2 0.330 dropping to 0.25 over 5 minutes then static
SHRTFTB1S1  0.0

Any ideas what we can check quickly/easily ?? Looks to me like the Lambda is simply not working

[Marks DTM Calib]

Whats the coolant temperature?

Also the MAF idle value when warm

[Marks DTM Calib]

The MAF value is about 9.1 Kg/h which is a bit low.

any sign of a vac leak, pipe not fitted on inlet, brake servo pipe ok?